Merge pull request #3373 from Abyss777/refactor_managers

Refactor managers, permissions etc

69 files changed, 785 insertions, 2591 deletions

diff --git a/setup/default.xml b/setup/default.xml
index 04530104a..f0f9ef4a3 100644
--- a/setup/default.xml
+++ b/setup/default.xml
@@ -60,7 +60,7 @@
         WHERE email = :email
     </entry>
 
-    <entry key='database.selectUsersAll'>
+    <entry key='database.selectUsers'>
         SELECT * FROM users
     </entry>
 
@@ -103,15 +103,15 @@
         DELETE FROM users WHERE id = :id
     </entry>
 
-    <entry key='database.selectDevicePermissions'>
+    <entry key='database.selectUserDevices'>
         SELECT userId, deviceId FROM user_device
     </entry>
 
-    <entry key='database.selectGroupPermissions'>
+    <entry key='database.selectUserGroups'>
         SELECT userId, groupId FROM user_group
     </entry>
 
-    <entry key='database.selectDevicesAll'>
+    <entry key='database.selectDevices'>
         SELECT * FROM devices
     </entry>
 
@@ -141,15 +141,15 @@
         DELETE FROM devices WHERE id = :id
     </entry>
 
-    <entry key='database.linkDevice'>
+    <entry key='database.linkUserDevice'>
         INSERT INTO user_device (userId, deviceId) VALUES (:userId, :deviceId)
     </entry>
 
-    <entry key='database.unlinkDevice'>
+    <entry key='database.unlinkUserDevice'>
         DELETE FROM user_device WHERE userId = :userId AND deviceId = :deviceId
     </entry>
 
-    <entry key='database.selectGroupsAll'>
+    <entry key='database.selectGroups'>
         SELECT * FROM groups
     </entry>
 
@@ -165,11 +165,11 @@
         DELETE FROM groups WHERE id = :id
     </entry>
 
-    <entry key='database.linkGroup'>
+    <entry key='database.linkUserGroup'>
         INSERT INTO user_group (userId, groupId) VALUES (:userId, :groupId)
     </entry>
 
-    <entry key='database.unlinkGroup'>
+    <entry key='database.unlinkUserGroup'>
         DELETE FROM user_group WHERE userId = :userId AND groupId = :groupId
     </entry>
 
@@ -207,7 +207,7 @@
         SELECT * FROM events WHERE deviceId = :deviceId AND serverTime BETWEEN :from AND :to ORDER BY serverTime
     </entry>
 
-    <entry key='database.selectGeofencesAll'>
+    <entry key='database.selectGeofences'>
         SELECT * FROM geofences
     </entry>
 
@@ -230,15 +230,15 @@
         DELETE FROM geofences WHERE id = :id
     </entry>
 
-    <entry key='database.selectGeofencePermissions'>
+    <entry key='database.selectUserGeofences'>
         SELECT userId, geofenceId FROM user_geofence
     </entry>
 
-    <entry key='database.linkGeofence'>
+    <entry key='database.linkUserGeofence'>
         INSERT INTO user_geofence (userId, geofenceId) VALUES (:userId, :geofenceId)
     </entry>
 
-    <entry key='database.unlinkGeofence'>
+    <entry key='database.unlinkUserGeofence'>
         DELETE FROM user_geofence WHERE userId = :userId AND geofenceId = :geofenceId
     </entry>
 
@@ -328,7 +328,7 @@
         VALUES (:captureTime, :activeUsers, :activeDevices, :requests, :messagesReceived, :messagesStored, :mailSent, :smsSent, :geocoderRequests, :geolocationRequests, :attributes)
     </entry>
     
-    <entry key='database.selectCalendarsAll'>
+    <entry key='database.selectCalendars'>
         SELECT * FROM calendars
     </entry>
 
@@ -349,27 +349,27 @@
         DELETE FROM calendars WHERE id = :id
     </entry>
 
-    <entry key='database.selectCalendarPermissions'>
+    <entry key='database.selectUserCalendars'>
         SELECT userId, calendarId FROM user_calendar
     </entry>
 
-    <entry key='database.linkCalendar'>
+    <entry key='database.linkUserCalendar'>
         INSERT INTO user_calendar (userId, calendarId) VALUES (:userId, :calendarId)
     </entry>
 
-    <entry key='database.unlinkCalendar'>
+    <entry key='database.unlinkUserCalendar'>
         DELETE FROM user_calendar WHERE userId = :userId AND calendarId = :calendarId
     </entry>
     
-    <entry key='database.selectUserPermissions'>
+    <entry key='database.selectUserUsers'>
         SELECT userId, managedUserId FROM user_user
     </entry>
 
-    <entry key='database.linkUser'>
+    <entry key='database.linkUserManagedUser'>
         INSERT INTO user_user (userId, managedUserId) VALUES (:userId, :managedUserId)
     </entry>
 
-    <entry key='database.unlinkUser'>
+    <entry key='database.unlinkUserManagedUser'>
         DELETE FROM user_user WHERE userId = :userId AND managedUserId = :managedUserId
     </entry>
 
@@ -395,15 +395,15 @@
         DELETE FROM attributes WHERE id = :id
     </entry>
     
-        <entry key='database.selectAttributePermissions'>
+        <entry key='database.selectUserAttributes'>
         SELECT userId, attributeId FROM user_attribute
     </entry>
 
-    <entry key='database.linkAttribute'>
+    <entry key='database.linkUserAttribute'>
         INSERT INTO user_attribute (userId, attributeId) VALUES (:userId, :attributeId)
     </entry>
 
-    <entry key='database.unlinkAttribute'>
+    <entry key='database.unlinkUserAttribute'>
         DELETE FROM user_attribute WHERE userId = :userId AND attributeId = :attributeId
     </entry>
 
@@ -452,15 +452,15 @@
         DELETE FROM drivers WHERE id = :id
     </entry>
     
-    <entry key='database.selectDriverPermissions'>
+    <entry key='database.selectUserDrivers'>
         SELECT userId, driverId FROM user_driver
     </entry>
 
-    <entry key='database.linkDriver'>
+    <entry key='database.linkUserDriver'>
         INSERT INTO user_driver (userId, driverId) VALUES (:userId, :driverId)
     </entry>
 
-    <entry key='database.unlinkDriver'>
+    <entry key='database.unlinkUserDriver'>
         DELETE FROM user_driver WHERE userId = :userId AND driverId = :driverId
     </entry>
 
diff --git a/src/org/traccar/BaseProtocolDecoder.java b/src/org/traccar/BaseProtocolDecoder.java
index cde858671..436ef9b02 100644
--- a/src/org/traccar/BaseProtocolDecoder.java
+++ b/src/org/traccar/BaseProtocolDecoder.java
@@ -52,9 +52,7 @@ public abstract class BaseProtocolDecoder extends ExtendedObjectDecoder {
 
             if (defaultGroupId != 0) {
                 Context.getPermissionsManager().refreshPermissions();
-                if (Context.getGeofenceManager() != null) {
-                    Context.getGeofenceManager().refresh();
-                }
+                Context.getPermissionsManager().refreshAllExtendedPermissions();
             }
 
             return device.getId();
diff --git a/src/org/traccar/api/BaseResource.java b/src/org/traccar/api/BaseResource.java
index 44ef33c53..cc272df9c 100644
--- a/src/org/traccar/api/BaseResource.java
+++ b/src/org/traccar/api/BaseResource.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2015 - 2016 Anton Tananaev (anton@traccar.org)
+ * Copyright 2015 - 2017 Anton Tananaev (anton@traccar.org)
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
diff --git a/src/org/traccar/api/resource/AttributePermissionResource.java b/src/org/traccar/api/resource/AttributePermissionResource.java
deleted file mode 100644
index 1924bcdf1..000000000
--- a/src/org/traccar/api/resource/AttributePermissionResource.java
+++ /dev/null
@@ -1,58 +0,0 @@
-/*
- * Copyright 2017 Anton Tananaev (anton@traccar.org)
- * Copyright 2017 Andrey Kunitsyn (andrey@traccar.org)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.traccar.api.resource;
-
-import java.sql.SQLException;
-
-import javax.ws.rs.Consumes;
-import javax.ws.rs.DELETE;
-import javax.ws.rs.POST;
-import javax.ws.rs.Path;
-import javax.ws.rs.Produces;
-import javax.ws.rs.core.MediaType;
-import javax.ws.rs.core.Response;
-
-import org.traccar.Context;
-import org.traccar.api.BaseResource;
-import org.traccar.model.AttributePermission;
-
-@Path("permissions/attributes")
-@Produces(MediaType.APPLICATION_JSON)
-@Consumes(MediaType.APPLICATION_JSON)
-public class AttributePermissionResource extends BaseResource {
-
-    @POST
-    public Response add(AttributePermission entity) throws SQLException {
-        Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkUser(getUserId(), entity.getUserId());
-        Context.getPermissionsManager().checkAttribute(getUserId(), entity.getAttributeId());
-        Context.getDataManager().linkAttribute(entity.getUserId(), entity.getAttributeId());
-        Context.getAttributesManager().refreshUserAttributes();
-        return Response.ok(entity).build();
-    }
-
-    @DELETE
-    public Response remove(AttributePermission entity) throws SQLException {
-        Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkUser(getUserId(), entity.getUserId());
-        Context.getPermissionsManager().checkAttribute(getUserId(), entity.getAttributeId());
-        Context.getDataManager().unlinkAttribute(entity.getUserId(), entity.getAttributeId());
-        Context.getAttributesManager().refreshUserAttributes();
-        return Response.noContent().build();
-    }
-
-}
diff --git a/src/org/traccar/api/resource/AttributeResource.java b/src/org/traccar/api/resource/AttributeResource.java
index 4d326779b..7b81d3ffb 100644
--- a/src/org/traccar/api/resource/AttributeResource.java
+++ b/src/org/traccar/api/resource/AttributeResource.java
@@ -38,6 +38,7 @@ import org.traccar.api.BaseResource;
 import org.traccar.database.AttributesManager;
 import org.traccar.model.Attribute;
 import org.traccar.model.Position;
+import org.traccar.model.User;
 import org.traccar.processing.ComputedAttributesHandler;
 
 @Path("attributes/computed")
@@ -52,42 +53,43 @@ public class AttributeResource extends BaseResource {
 
         AttributesManager attributesManager = Context.getAttributesManager();
         if (refresh) {
-            attributesManager.refreshAttributes();
+            attributesManager.refreshItems();
         }
 
         Set<Long> result = new HashSet<>();
         if (all) {
             if (Context.getPermissionsManager().isAdmin(getUserId())) {
-                result.addAll(attributesManager.getAllAttributes());
+                result.addAll(attributesManager.getAllItems());
             } else {
                 Context.getPermissionsManager().checkManager(getUserId());
-                result.addAll(attributesManager.getManagedAttributes(getUserId()));
+                result.addAll(attributesManager.getManagedItems(getUserId()));
             }
         } else {
             if (userId == 0) {
                 userId = getUserId();
             }
             Context.getPermissionsManager().checkUser(getUserId(), userId);
-            result.addAll(attributesManager.getUserAttributes(userId));
+            result.addAll(attributesManager.getUserItems(userId));
         }
 
         if (groupId != 0) {
             Context.getPermissionsManager().checkGroup(getUserId(), groupId);
-            result.retainAll(attributesManager.getGroupAttributes(groupId));
+            result.retainAll(attributesManager.getGroupItems(groupId));
         }
 
         if (deviceId != 0) {
             Context.getPermissionsManager().checkDevice(getUserId(), deviceId);
-            result.retainAll(attributesManager.getDeviceAttributes(deviceId));
+            result.retainAll(attributesManager.getDeviceItems(deviceId));
         }
-        return attributesManager.getAttributes(result);
+        return attributesManager.getItems(Attribute.class, result);
 
     }
 
     private Response add(Attribute entity) throws SQLException {
-        Context.getAttributesManager().addAttribute(entity);
-        Context.getDataManager().linkAttribute(getUserId(), entity.getId());
-        Context.getAttributesManager().refreshUserAttributes();
+        Context.getPermissionsManager().checkReadonly(getUserId());
+        Context.getAttributesManager().addItem(entity);
+        Context.getDataManager().linkObject(User.class, getUserId(), entity.getClass(), entity.getId(), true);
+        Context.getAttributesManager().refreshUserItems();
         return Response.ok(entity).build();
     }
 
@@ -127,8 +129,8 @@ public class AttributeResource extends BaseResource {
     @PUT
     public Response update(Attribute entity) throws SQLException {
         Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkAttribute(getUserId(), entity.getId());
-        Context.getAttributesManager().updateAttribute(entity);
+        Context.getPermissionsManager().checkPermission(Attribute.class, getUserId(), entity.getId());
+        Context.getAttributesManager().updateItem(entity);
         return Response.ok(entity).build();
     }
 
@@ -136,8 +138,8 @@ public class AttributeResource extends BaseResource {
     @DELETE
     public Response remove(@PathParam("id") long id) throws SQLException {
         Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkAttribute(getUserId(), id);
-        Context.getAttributesManager().removeAttribute(id);
+        Context.getPermissionsManager().checkPermission(Attribute.class, getUserId(), id);
+        Context.getAttributesManager().removeItem(id);
         return Response.noContent().build();
     }
 
diff --git a/src/org/traccar/api/resource/CalendarPermissionResource.java b/src/org/traccar/api/resource/CalendarPermissionResource.java
deleted file mode 100644
index a49254b6b..000000000
--- a/src/org/traccar/api/resource/CalendarPermissionResource.java
+++ /dev/null
@@ -1,57 +0,0 @@
-/*
- * Copyright 2016 Anton Tananaev (anton@traccar.org)
- * Copyright 2016 Andrey Kunitsyn (andrey@traccar.org)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.traccar.api.resource;
-
-import java.sql.SQLException;
-
-import javax.ws.rs.Consumes;
-import javax.ws.rs.DELETE;
-import javax.ws.rs.POST;
-import javax.ws.rs.Path;
-import javax.ws.rs.Produces;
-import javax.ws.rs.core.MediaType;
-import javax.ws.rs.core.Response;
-
-import org.traccar.Context;
-import org.traccar.api.BaseResource;
-import org.traccar.model.CalendarPermission;
-
-@Path("permissions/calendars")
-@Produces(MediaType.APPLICATION_JSON)
-@Consumes(MediaType.APPLICATION_JSON)
-public class CalendarPermissionResource extends BaseResource {
-
-    @POST
-    public Response add(CalendarPermission entity) throws SQLException {
-        Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkUser(getUserId(), entity.getUserId());
-        Context.getPermissionsManager().checkCalendar(getUserId(), entity.getCalendarId());
-        Context.getDataManager().linkCalendar(entity.getUserId(), entity.getCalendarId());
-        Context.getCalendarManager().refreshUserCalendars();
-        return Response.ok(entity).build();
-    }
-
-    @DELETE
-    public Response remove(CalendarPermission entity) throws SQLException {
-        Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkUser(getUserId(), entity.getUserId());
-        Context.getPermissionsManager().checkCalendar(getUserId(), entity.getCalendarId());
-        Context.getDataManager().unlinkCalendar(entity.getUserId(), entity.getCalendarId());
-        Context.getCalendarManager().refreshUserCalendars();
-        return Response.noContent().build();
-    }
-}
diff --git a/src/org/traccar/api/resource/CalendarResource.java b/src/org/traccar/api/resource/CalendarResource.java
index 641d3b4b5..a0f8656af 100644
--- a/src/org/traccar/api/resource/CalendarResource.java
+++ b/src/org/traccar/api/resource/CalendarResource.java
@@ -33,7 +33,9 @@ import javax.ws.rs.core.Response;
 
 import org.traccar.Context;
 import org.traccar.api.BaseResource;
+import org.traccar.database.CalendarManager;
 import org.traccar.model.Calendar;
+import org.traccar.model.User;
 
 @Path("calendars")
 @Produces(MediaType.APPLICATION_JSON)
@@ -44,28 +46,29 @@ public class CalendarResource extends BaseResource {
     public Collection<Calendar> get(
             @QueryParam("all") boolean all, @QueryParam("userId") long userId) throws SQLException {
 
+        CalendarManager calendarManager = Context.getCalendarManager();
         if (all) {
             if (Context.getPermissionsManager().isAdmin(getUserId())) {
-                return Context.getCalendarManager().getAllCalendars();
+                return calendarManager.getItems(Calendar.class, calendarManager.getAllItems());
             } else {
                 Context.getPermissionsManager().checkManager(getUserId());
-                return Context.getCalendarManager().getManagedCalendars(getUserId());
+                return calendarManager.getItems(Calendar.class, calendarManager.getManagedItems(getUserId()));
             }
         } else {
             if (userId == 0) {
                 userId = getUserId();
             }
             Context.getPermissionsManager().checkUser(getUserId(), userId);
-            return Context.getCalendarManager().getUserCalendars(userId);
+            return calendarManager.getItems(Calendar.class, calendarManager.getUserItems(userId));
         }
     }
 
     @POST
     public Response add(Calendar entity) throws SQLException {
         Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getCalendarManager().addCalendar(entity);
-        Context.getDataManager().linkCalendar(getUserId(), entity.getId());
-        Context.getCalendarManager().refreshUserCalendars();
+        Context.getCalendarManager().addItem(entity);
+        Context.getDataManager().linkObject(User.class, getUserId(), entity.getClass(), entity.getId(), true);
+        Context.getCalendarManager().refreshUserItems();
         return Response.ok(entity).build();
     }
 
@@ -73,8 +76,8 @@ public class CalendarResource extends BaseResource {
     @PUT
     public Response update(Calendar entity) throws SQLException {
         Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkCalendar(getUserId(), entity.getId());
-        Context.getCalendarManager().updateCalendar(entity);
+        Context.getPermissionsManager().checkPermission(Calendar.class, getUserId(), entity.getId());
+        Context.getCalendarManager().updateItem(entity);
         return Response.ok(entity).build();
     }
 
@@ -82,8 +85,8 @@ public class CalendarResource extends BaseResource {
     @DELETE
     public Response remove(@PathParam("id") long id) throws SQLException {
         Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkCalendar(getUserId(), id);
-        Context.getCalendarManager().removeCalendar(id);
+        Context.getPermissionsManager().checkPermission(Calendar.class, getUserId(), id);
+        Context.getCalendarManager().removeItem(id);
         return Response.noContent().build();
     }
 }
diff --git a/src/org/traccar/api/resource/DeviceAttributeResource.java b/src/org/traccar/api/resource/DeviceAttributeResource.java
deleted file mode 100644
index 82d17bcc6..000000000
--- a/src/org/traccar/api/resource/DeviceAttributeResource.java
+++ /dev/null
@@ -1,58 +0,0 @@
-/*
- * Copyright 2017 Anton Tananaev (anton@traccar.org)
- * Copyright 2017 Andrey Kunitsyn (andrey@traccar.org)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.traccar.api.resource;
-
-import java.sql.SQLException;
-
-import javax.ws.rs.Consumes;
-import javax.ws.rs.DELETE;
-import javax.ws.rs.POST;
-import javax.ws.rs.Path;
-import javax.ws.rs.Produces;
-import javax.ws.rs.core.MediaType;
-import javax.ws.rs.core.Response;
-
-import org.traccar.Context;
-import org.traccar.api.BaseResource;
-import org.traccar.model.DeviceAttribute;
-
-@Path("devices/attributes")
-@Produces(MediaType.APPLICATION_JSON)
-@Consumes(MediaType.APPLICATION_JSON)
-public class DeviceAttributeResource extends BaseResource {
-
-    @POST
-    public Response add(DeviceAttribute entity) throws SQLException {
-        Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkDevice(getUserId(), entity.getDeviceId());
-        Context.getPermissionsManager().checkAttribute(getUserId(), entity.getAttributeId());
-        Context.getDataManager().linkDeviceAttribute(entity.getDeviceId(), entity.getAttributeId());
-        Context.getAttributesManager().refresh();
-        return Response.ok(entity).build();
-    }
-
-    @DELETE
-    public Response remove(DeviceAttribute entity) throws SQLException {
-        Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkDevice(getUserId(), entity.getDeviceId());
-        Context.getPermissionsManager().checkAttribute(getUserId(), entity.getAttributeId());
-        Context.getDataManager().unlinkDeviceAttribute(entity.getDeviceId(), entity.getAttributeId());
-        Context.getAttributesManager().refresh();
-        return Response.noContent().build();
-    }
-
-}
diff --git a/src/org/traccar/api/resource/DeviceDriverResource.java b/src/org/traccar/api/resource/DeviceDriverResource.java
deleted file mode 100644
index 341c50909..000000000
--- a/src/org/traccar/api/resource/DeviceDriverResource.java
+++ /dev/null
@@ -1,58 +0,0 @@
-/*
- * Copyright 2017 Anton Tananaev (anton@traccar.org)
- * Copyright 2017 Andrey Kunitsyn (andrey@traccar.org)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.traccar.api.resource;
-
-import java.sql.SQLException;
-
-import javax.ws.rs.Consumes;
-import javax.ws.rs.DELETE;
-import javax.ws.rs.POST;
-import javax.ws.rs.Path;
-import javax.ws.rs.Produces;
-import javax.ws.rs.core.MediaType;
-import javax.ws.rs.core.Response;
-
-import org.traccar.Context;
-import org.traccar.api.BaseResource;
-import org.traccar.model.DeviceDriver;
-
-@Path("devices/drivers")
-@Produces(MediaType.APPLICATION_JSON)
-@Consumes(MediaType.APPLICATION_JSON)
-public class DeviceDriverResource extends BaseResource {
-
-    @POST
-    public Response add(DeviceDriver entity) throws SQLException {
-        Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkDevice(getUserId(), entity.getDeviceId());
-        Context.getPermissionsManager().checkDriver(getUserId(), entity.getDriverId());
-        Context.getDataManager().linkDeviceDriver(entity.getDeviceId(), entity.getDriverId());
-        Context.getDriversManager().refresh();
-        return Response.ok(entity).build();
-    }
-
-    @DELETE
-    public Response remove(DeviceDriver entity) throws SQLException {
-        Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkDevice(getUserId(), entity.getDeviceId());
-        Context.getPermissionsManager().checkDriver(getUserId(), entity.getDriverId());
-        Context.getDataManager().unlinkDeviceDriver(entity.getDeviceId(), entity.getDriverId());
-        Context.getDriversManager().refresh();
-        return Response.noContent().build();
-    }
-
-}
diff --git a/src/org/traccar/api/resource/DeviceGeofenceResource.java b/src/org/traccar/api/resource/DeviceGeofenceResource.java
deleted file mode 100644
index 6254fe3cf..000000000
--- a/src/org/traccar/api/resource/DeviceGeofenceResource.java
+++ /dev/null
@@ -1,57 +0,0 @@
-/*
- * Copyright 2016 Anton Tananaev (anton@traccar.org)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.traccar.api.resource;
-
-import org.traccar.Context;
-import org.traccar.api.BaseResource;
-import org.traccar.model.DeviceGeofence;
-
-import javax.ws.rs.Consumes;
-import javax.ws.rs.DELETE;
-import javax.ws.rs.POST;
-import javax.ws.rs.Path;
-import javax.ws.rs.Produces;
-import javax.ws.rs.core.MediaType;
-import javax.ws.rs.core.Response;
-
-import java.sql.SQLException;
-
-@Path("devices/geofences")
-@Produces(MediaType.APPLICATION_JSON)
-@Consumes(MediaType.APPLICATION_JSON)
-public class DeviceGeofenceResource extends BaseResource {
-
-    @POST
-    public Response add(DeviceGeofence entity) throws SQLException {
-        Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkDevice(getUserId(), entity.getDeviceId());
-        Context.getPermissionsManager().checkGeofence(getUserId(), entity.getGeofenceId());
-        Context.getDataManager().linkDeviceGeofence(entity.getDeviceId(), entity.getGeofenceId());
-        Context.getGeofenceManager().refresh();
-        return Response.ok(entity).build();
-    }
-
-    @DELETE
-    public Response remove(DeviceGeofence entity) throws SQLException {
-        Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkDevice(getUserId(), entity.getDeviceId());
-        Context.getPermissionsManager().checkGeofence(getUserId(), entity.getGeofenceId());
-        Context.getDataManager().unlinkDeviceGeofence(entity.getDeviceId(), entity.getGeofenceId());
-        Context.getGeofenceManager().refresh();
-        return Response.noContent().build();
-    }
-
-}
diff --git a/src/org/traccar/api/resource/DevicePermissionResource.java b/src/org/traccar/api/resource/DevicePermissionResource.java
deleted file mode 100644
index 6e00dc47f..000000000
--- a/src/org/traccar/api/resource/DevicePermissionResource.java
+++ /dev/null
@@ -1,66 +0,0 @@
-/*
- * Copyright 2015 - 2017 Anton Tananaev (anton@traccar.org)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.traccar.api.resource;
-
-import org.traccar.Context;
-import org.traccar.api.BaseResource;
-import org.traccar.model.DevicePermission;
-
-import javax.ws.rs.Consumes;
-import javax.ws.rs.DELETE;
-import javax.ws.rs.POST;
-import javax.ws.rs.Path;
-import javax.ws.rs.Produces;
-import javax.ws.rs.core.MediaType;
-import javax.ws.rs.core.Response;
-import java.sql.SQLException;
-
-@Path("permissions/devices")
-@Produces(MediaType.APPLICATION_JSON)
-@Consumes(MediaType.APPLICATION_JSON)
-public class DevicePermissionResource extends BaseResource {
-
-    @POST
-    public Response add(DevicePermission entity) throws SQLException {
-        Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkUser(getUserId(), entity.getUserId());
-        Context.getPermissionsManager().checkDevice(getUserId(), entity.getDeviceId());
-        Context.getDataManager().linkDevice(entity.getUserId(), entity.getDeviceId());
-        Context.getPermissionsManager().refreshPermissions();
-        if (Context.getGeofenceManager() != null) {
-            Context.getGeofenceManager().refresh();
-        }
-        return Response.ok(entity).build();
-    }
-
-    @DELETE
-    public Response remove(DevicePermission entity) throws SQLException {
-        Context.getPermissionsManager().checkReadonly(getUserId());
-        if (getUserId() != entity.getUserId()) {
-            Context.getPermissionsManager().checkUser(getUserId(), entity.getUserId());
-        } else {
-            Context.getPermissionsManager().checkAdmin(getUserId());
-        }
-        Context.getPermissionsManager().checkDevice(getUserId(), entity.getDeviceId());
-        Context.getDataManager().unlinkDevice(entity.getUserId(), entity.getDeviceId());
-        Context.getPermissionsManager().refreshPermissions();
-        if (Context.getGeofenceManager() != null) {
-            Context.getGeofenceManager().refresh();
-        }
-        return Response.noContent().build();
-    }
-
-}
diff --git a/src/org/traccar/api/resource/DeviceResource.java b/src/org/traccar/api/resource/DeviceResource.java
index 2957d623c..6cf7a6219 100644
--- a/src/org/traccar/api/resource/DeviceResource.java
+++ b/src/org/traccar/api/resource/DeviceResource.java
@@ -19,6 +19,7 @@ import org.traccar.Context;
 import org.traccar.api.BaseResource;
 import org.traccar.model.Device;
 import org.traccar.model.DeviceTotalDistance;
+import org.traccar.model.User;
 
 import javax.ws.rs.Consumes;
 import javax.ws.rs.DELETE;
@@ -83,11 +84,9 @@ public class DeviceResource extends BaseResource {
         Context.getPermissionsManager().checkDeviceReadonly(getUserId());
         Context.getPermissionsManager().checkDeviceLimit(getUserId());
         Context.getDeviceManager().addDevice(entity);
-        Context.getDataManager().linkDevice(getUserId(), entity.getId());
+        Context.getDataManager().linkObject(User.class, getUserId(), entity.getClass(), entity.getId(), true);
         Context.getPermissionsManager().refreshPermissions();
-        if (Context.getGeofenceManager() != null) {
-            Context.getGeofenceManager().refresh();
-        }
+        Context.getPermissionsManager().refreshAllExtendedPermissions();
         return Response.ok(entity).build();
     }
 
@@ -99,9 +98,7 @@ public class DeviceResource extends BaseResource {
         Context.getPermissionsManager().checkDevice(getUserId(), entity.getId());
         Context.getDeviceManager().updateDevice(entity);
         Context.getPermissionsManager().refreshPermissions();
-        if (Context.getGeofenceManager() != null) {
-            Context.getGeofenceManager().refresh();
-        }
+        Context.getPermissionsManager().refreshAllExtendedPermissions();
         return Response.ok(entity).build();
     }
 
@@ -113,9 +110,7 @@ public class DeviceResource extends BaseResource {
         Context.getPermissionsManager().checkDevice(getUserId(), id);
         Context.getDeviceManager().removeDevice(id);
         Context.getPermissionsManager().refreshPermissions();
-        if (Context.getGeofenceManager() != null) {
-            Context.getGeofenceManager().refresh();
-        }
+        Context.getPermissionsManager().refreshAllExtendedPermissions();
         Context.getAliasesManager().removeDevice(id);
         return Response.noContent().build();
     }
diff --git a/src/org/traccar/api/resource/DriverPermissionResource.java b/src/org/traccar/api/resource/DriverPermissionResource.java
deleted file mode 100644
index fd1ca7c6d..000000000
--- a/src/org/traccar/api/resource/DriverPermissionResource.java
+++ /dev/null
@@ -1,59 +0,0 @@
-/*
- * Copyright 2017 Anton Tananaev (anton@traccar.org)
- * Copyright 2017 Andrey Kunitsyn (andrey@traccar.org)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.traccar.api.resource;
-
-import java.sql.SQLException;
-
-import javax.ws.rs.Consumes;
-import javax.ws.rs.DELETE;
-import javax.ws.rs.POST;
-import javax.ws.rs.Path;
-import javax.ws.rs.Produces;
-import javax.ws.rs.core.MediaType;
-import javax.ws.rs.core.Response;
-
-import org.traccar.Context;
-import org.traccar.api.BaseResource;
-
-import org.traccar.model.DriverPermission;
-
-@Path("permissions/drivers")
-@Produces(MediaType.APPLICATION_JSON)
-@Consumes(MediaType.APPLICATION_JSON)
-public class DriverPermissionResource extends BaseResource {
-
-    @POST
-    public Response add(DriverPermission entity) throws SQLException {
-        Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkUser(getUserId(), entity.getUserId());
-        Context.getPermissionsManager().checkDriver(getUserId(), entity.getDriverId());
-        Context.getDataManager().linkDriver(entity.getUserId(), entity.getDriverId());
-        Context.getDriversManager().refreshUserDrivers();
-        return Response.ok(entity).build();
-    }
-
-    @DELETE
-    public Response remove(DriverPermission entity) throws SQLException {
-        Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkUser(getUserId(), entity.getUserId());
-        Context.getPermissionsManager().checkDriver(getUserId(), entity.getDriverId());
-        Context.getDataManager().unlinkDriver(entity.getUserId(), entity.getDriverId());
-        Context.getDriversManager().refreshUserDrivers();
-        return Response.noContent().build();
-    }
-
-}
diff --git a/src/org/traccar/api/resource/DriverResource.java b/src/org/traccar/api/resource/DriverResource.java
index 7fe0af473..72eadb711 100644
--- a/src/org/traccar/api/resource/DriverResource.java
+++ b/src/org/traccar/api/resource/DriverResource.java
@@ -37,6 +37,7 @@ import org.traccar.Context;
 import org.traccar.api.BaseResource;
 import org.traccar.database.DriversManager;
 import org.traccar.model.Driver;
+import org.traccar.model.User;
 
 @Path("drivers")
 @Produces(MediaType.APPLICATION_JSON)
@@ -50,44 +51,44 @@ public class DriverResource extends BaseResource {
 
         DriversManager driversManager = Context.getDriversManager();
         if (refresh) {
-            driversManager.refreshDrivers();
+            driversManager.refreshItems();
         }
 
         Set<Long> result = new HashSet<>();
         if (all) {
             if (Context.getPermissionsManager().isAdmin(getUserId())) {
-                result.addAll(driversManager.getAllDrivers());
+                result.addAll(driversManager.getAllItems());
             } else {
                 Context.getPermissionsManager().checkManager(getUserId());
-                result.addAll(driversManager.getManagedDrivers(getUserId()));
+                result.addAll(driversManager.getManagedItems(getUserId()));
             }
         } else {
             if (userId == 0) {
                 userId = getUserId();
             }
             Context.getPermissionsManager().checkUser(getUserId(), userId);
-            result.addAll(driversManager.getUserDrivers(userId));
+            result.addAll(driversManager.getUserItems(userId));
         }
 
         if (groupId != 0) {
             Context.getPermissionsManager().checkGroup(getUserId(), groupId);
-            result.retainAll(driversManager.getGroupDrivers(groupId));
+            result.retainAll(driversManager.getGroupItems(groupId));
         }
 
         if (deviceId != 0) {
             Context.getPermissionsManager().checkDevice(getUserId(), deviceId);
-            result.retainAll(driversManager.getDeviceDrivers(deviceId));
+            result.retainAll(driversManager.getDeviceItems(deviceId));
         }
-        return driversManager.getDrivers(result);
+        return driversManager.getItems(Driver.class, result);
 
     }
 
     @POST
     public Response add(Driver entity) throws SQLException {
         Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getDriversManager().addDriver(entity);
-        Context.getDataManager().linkDriver(getUserId(), entity.getId());
-        Context.getDriversManager().refreshUserDrivers();
+        Context.getDriversManager().addItem(entity);
+        Context.getDataManager().linkObject(User.class, getUserId(), entity.getClass(), entity.getId(), true);
+        Context.getDriversManager().refreshUserItems();
         return Response.ok(entity).build();
     }
 
@@ -95,8 +96,8 @@ public class DriverResource extends BaseResource {
     @PUT
     public Response update(Driver entity) throws SQLException {
         Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkDriver(getUserId(), entity.getId());
-        Context.getDriversManager().updateDriver(entity);
+        Context.getPermissionsManager().checkPermission(Driver.class, getUserId(), entity.getId());
+        Context.getDriversManager().updateItem(entity);
         return Response.ok(entity).build();
     }
 
@@ -104,8 +105,8 @@ public class DriverResource extends BaseResource {
     @DELETE
     public Response remove(@PathParam("id") long id) throws SQLException {
         Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkDriver(getUserId(), id);
-        Context.getDriversManager().removeDriver(id);
+        Context.getPermissionsManager().checkPermission(Driver.class, getUserId(), id);
+        Context.getDriversManager().removeItem(id);
         return Response.noContent().build();
     }
 
diff --git a/src/org/traccar/api/resource/EventResource.java b/src/org/traccar/api/resource/EventResource.java
index 0ef5456af..b7fda6f73 100644
--- a/src/org/traccar/api/resource/EventResource.java
+++ b/src/org/traccar/api/resource/EventResource.java
@@ -12,6 +12,7 @@ import javax.ws.rs.core.MediaType;
 import org.traccar.Context;
 import org.traccar.api.BaseResource;
 import org.traccar.model.Event;
+import org.traccar.model.Geofence;
 
 @Path("events")
 @Produces(MediaType.APPLICATION_JSON)
@@ -25,7 +26,7 @@ public class EventResource extends BaseResource {
         Event event = Context.getDataManager().getEvent(id);
         Context.getPermissionsManager().checkDevice(getUserId(), event.getDeviceId());
         if (event.getGeofenceId() != 0) {
-            Context.getPermissionsManager().checkGeofence(getUserId(), event.getGeofenceId());
+            Context.getPermissionsManager().checkPermission(Geofence.class, getUserId(), event.getGeofenceId());
         }
         return event;
     }
diff --git a/src/org/traccar/api/resource/GeofencePermissionResource.java b/src/org/traccar/api/resource/GeofencePermissionResource.java
deleted file mode 100644
index 8faa63d85..000000000
--- a/src/org/traccar/api/resource/GeofencePermissionResource.java
+++ /dev/null
@@ -1,56 +0,0 @@
-/*
- * Copyright 2016 Anton Tananaev (anton@traccar.org)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.traccar.api.resource;
-
-import org.traccar.Context;
-import org.traccar.api.BaseResource;
-import org.traccar.model.GeofencePermission;
-
-import javax.ws.rs.Consumes;
-import javax.ws.rs.DELETE;
-import javax.ws.rs.POST;
-import javax.ws.rs.Path;
-import javax.ws.rs.Produces;
-import javax.ws.rs.core.MediaType;
-import javax.ws.rs.core.Response;
-import java.sql.SQLException;
-
-@Path("permissions/geofences")
-@Produces(MediaType.APPLICATION_JSON)
-@Consumes(MediaType.APPLICATION_JSON)
-public class GeofencePermissionResource extends BaseResource {
-
-    @POST
-    public Response add(GeofencePermission entity) throws SQLException {
-        Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkUser(getUserId(), entity.getUserId());
-        Context.getPermissionsManager().checkGeofence(getUserId(), entity.getGeofenceId());
-        Context.getDataManager().linkGeofence(entity.getUserId(), entity.getGeofenceId());
-        Context.getGeofenceManager().refreshUserGeofences();
-        return Response.ok(entity).build();
-    }
-
-    @DELETE
-    public Response remove(GeofencePermission entity) throws SQLException {
-        Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkUser(getUserId(), entity.getUserId());
-        Context.getPermissionsManager().checkGeofence(getUserId(), entity.getGeofenceId());
-        Context.getDataManager().unlinkGeofence(entity.getUserId(), entity.getGeofenceId());
-        Context.getGeofenceManager().refreshUserGeofences();
-        return Response.noContent().build();
-    }
-
-}
diff --git a/src/org/traccar/api/resource/GeofenceResource.java b/src/org/traccar/api/resource/GeofenceResource.java
index d5acf106a..47f889e9c 100644
--- a/src/org/traccar/api/resource/GeofenceResource.java
+++ b/src/org/traccar/api/resource/GeofenceResource.java
@@ -19,6 +19,7 @@ import org.traccar.Context;
 import org.traccar.api.BaseResource;
 import org.traccar.database.GeofenceManager;
 import org.traccar.model.Geofence;
+import org.traccar.model.User;
 
 import javax.ws.rs.Consumes;
 import javax.ws.rs.DELETE;
@@ -49,44 +50,44 @@ public class GeofenceResource extends BaseResource {
 
         GeofenceManager geofenceManager = Context.getGeofenceManager();
         if (refresh) {
-            geofenceManager.refreshGeofences();
+            geofenceManager.refreshItems();
         }
 
         Set<Long> result = new HashSet<>();
         if (all) {
             if (Context.getPermissionsManager().isAdmin(getUserId())) {
-                result.addAll(geofenceManager.getAllGeofencesIds());
+                result.addAll(geofenceManager.getAllItems());
             } else {
                 Context.getPermissionsManager().checkManager(getUserId());
-                result.addAll(geofenceManager.getManagedGeofencesIds(getUserId()));
+                result.addAll(geofenceManager.getManagedItems(getUserId()));
             }
         } else {
             if (userId == 0) {
                 userId = getUserId();
             }
             Context.getPermissionsManager().checkUser(getUserId(), userId);
-            result.addAll(geofenceManager.getUserGeofencesIds(userId));
+            result.addAll(geofenceManager.getUserItems(userId));
         }
 
         if (groupId != 0) {
             Context.getPermissionsManager().checkGroup(getUserId(), groupId);
-            result.retainAll(geofenceManager.getGroupGeofencesIds(groupId));
+            result.retainAll(geofenceManager.getGroupItems(groupId));
         }
 
         if (deviceId != 0) {
             Context.getPermissionsManager().checkDevice(getUserId(), deviceId);
-            result.retainAll(geofenceManager.getDeviceGeofencesIds(deviceId));
+            result.retainAll(geofenceManager.getDeviceItems(deviceId));
         }
-        return geofenceManager.getGeofences(result);
+        return geofenceManager.getItems(Geofence.class, result);
 
     }
 
     @POST
     public Response add(Geofence entity) throws SQLException {
         Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getDataManager().addGeofence(entity);
-        Context.getDataManager().linkGeofence(getUserId(), entity.getId());
-        Context.getGeofenceManager().refreshGeofences();
+        Context.getGeofenceManager().addItem(entity);
+        Context.getDataManager().linkObject(User.class, getUserId(), entity.getClass(), entity.getId(), true);
+        Context.getGeofenceManager().refreshUserItems();
         return Response.ok(entity).build();
     }
 
@@ -94,8 +95,8 @@ public class GeofenceResource extends BaseResource {
     @PUT
     public Response update(Geofence entity) throws SQLException {
         Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkGeofence(getUserId(), entity.getId());
-        Context.getGeofenceManager().updateGeofence(entity);
+        Context.getPermissionsManager().checkPermission(Geofence.class, getUserId(), entity.getId());
+        Context.getGeofenceManager().updateItem(entity);
         return Response.ok(entity).build();
     }
 
@@ -103,9 +104,8 @@ public class GeofenceResource extends BaseResource {
     @DELETE
     public Response remove(@PathParam("id") long id) throws SQLException {
         Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkGeofence(getUserId(), id);
-        Context.getDataManager().removeGeofence(id);
-        Context.getGeofenceManager().refreshGeofences();
+        Context.getPermissionsManager().checkPermission(Geofence.class, getUserId(), id);
+        Context.getGeofenceManager().removeItem(id);
         return Response.noContent().build();
     }
 
diff --git a/src/org/traccar/api/resource/GroupAttributeResource.java b/src/org/traccar/api/resource/GroupAttributeResource.java
deleted file mode 100644
index d8b8b58c9..000000000
--- a/src/org/traccar/api/resource/GroupAttributeResource.java
+++ /dev/null
@@ -1,58 +0,0 @@
-/*
- * Copyright 2017 Anton Tananaev (anton@traccar.org)
- * Copyright 2017 Andrey Kunitsyn (andrey@traccar.org)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.traccar.api.resource;
-
-import java.sql.SQLException;
-
-import javax.ws.rs.Consumes;
-import javax.ws.rs.DELETE;
-import javax.ws.rs.POST;
-import javax.ws.rs.Path;
-import javax.ws.rs.Produces;
-import javax.ws.rs.core.MediaType;
-import javax.ws.rs.core.Response;
-
-import org.traccar.Context;
-import org.traccar.api.BaseResource;
-import org.traccar.model.GroupAttribute;
-
-@Path("groups/attributes")
-@Produces(MediaType.APPLICATION_JSON)
-@Consumes(MediaType.APPLICATION_JSON)
-public class GroupAttributeResource extends BaseResource {
-
-    @POST
-    public Response add(GroupAttribute entity) throws SQLException {
-        Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkGroup(getUserId(), entity.getGroupId());
-        Context.getPermissionsManager().checkAttribute(getUserId(), entity.getAttributeId());
-        Context.getDataManager().linkGroupAttribute(entity.getGroupId(), entity.getAttributeId());
-        Context.getAttributesManager().refresh();
-        return Response.ok(entity).build();
-    }
-
-    @DELETE
-    public Response remove(GroupAttribute entity) throws SQLException {
-        Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkGroup(getUserId(), entity.getGroupId());
-        Context.getPermissionsManager().checkAttribute(getUserId(), entity.getAttributeId());
-        Context.getDataManager().unlinkGroupAttribute(entity.getGroupId(), entity.getAttributeId());
-        Context.getAttributesManager().refresh();
-        return Response.noContent().build();
-    }
-
-}
diff --git a/src/org/traccar/api/resource/GroupDriverResource.java b/src/org/traccar/api/resource/GroupDriverResource.java
deleted file mode 100644
index 76fc2892c..000000000
--- a/src/org/traccar/api/resource/GroupDriverResource.java
+++ /dev/null
@@ -1,58 +0,0 @@
-/*
- * Copyright 2017 Anton Tananaev (anton@traccar.org)
- * Copyright 2017 Andrey Kunitsyn (andrey@traccar.org)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.traccar.api.resource;
-
-import java.sql.SQLException;
-
-import javax.ws.rs.Consumes;
-import javax.ws.rs.DELETE;
-import javax.ws.rs.POST;
-import javax.ws.rs.Path;
-import javax.ws.rs.Produces;
-import javax.ws.rs.core.MediaType;
-import javax.ws.rs.core.Response;
-
-import org.traccar.Context;
-import org.traccar.api.BaseResource;
-import org.traccar.model.GroupDriver;
-
-@Path("groups/drivers")
-@Produces(MediaType.APPLICATION_JSON)
-@Consumes(MediaType.APPLICATION_JSON)
-public class GroupDriverResource extends BaseResource {
-
-    @POST
-    public Response add(GroupDriver entity) throws SQLException {
-        Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkGroup(getUserId(), entity.getGroupId());
-        Context.getPermissionsManager().checkDriver(getUserId(), entity.getDriverId());
-        Context.getDataManager().linkGroupDriver(entity.getGroupId(), entity.getDriverId());
-        Context.getDriversManager().refresh();
-        return Response.ok(entity).build();
-    }
-
-    @DELETE
-    public Response remove(GroupDriver entity) throws SQLException {
-        Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkGroup(getUserId(), entity.getGroupId());
-        Context.getPermissionsManager().checkDriver(getUserId(), entity.getDriverId());
-        Context.getDataManager().unlinkGroupDriver(entity.getGroupId(), entity.getDriverId());
-        Context.getDriversManager().refresh();
-        return Response.noContent().build();
-    }
-
-}
diff --git a/src/org/traccar/api/resource/GroupGeofenceResource.java b/src/org/traccar/api/resource/GroupGeofenceResource.java
deleted file mode 100644
index 81fd4e45f..000000000
--- a/src/org/traccar/api/resource/GroupGeofenceResource.java
+++ /dev/null
@@ -1,56 +0,0 @@
-/*
- * Copyright 2016 Anton Tananaev (anton@traccar.org)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.traccar.api.resource;
-
-import org.traccar.Context;
-import org.traccar.api.BaseResource;
-import org.traccar.model.GroupGeofence;
-
-import javax.ws.rs.Consumes;
-import javax.ws.rs.DELETE;
-import javax.ws.rs.POST;
-import javax.ws.rs.Path;
-import javax.ws.rs.Produces;
-import javax.ws.rs.core.MediaType;
-import javax.ws.rs.core.Response;
-import java.sql.SQLException;
-
-@Path("groups/geofences")
-@Produces(MediaType.APPLICATION_JSON)
-@Consumes(MediaType.APPLICATION_JSON)
-public class GroupGeofenceResource extends BaseResource {
-
-    @POST
-    public Response add(GroupGeofence entity) throws SQLException {
-        Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkGroup(getUserId(), entity.getGroupId());
-        Context.getPermissionsManager().checkGeofence(getUserId(), entity.getGeofenceId());
-        Context.getDataManager().linkGroupGeofence(entity.getGroupId(), entity.getGeofenceId());
-        Context.getGeofenceManager().refresh();
-        return Response.ok(entity).build();
-    }
-
-    @DELETE
-    public Response remove(GroupGeofence entity) throws SQLException {
-        Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkGroup(getUserId(), entity.getGroupId());
-        Context.getPermissionsManager().checkGeofence(getUserId(), entity.getGeofenceId());
-        Context.getDataManager().unlinkGroupGeofence(entity.getGroupId(), entity.getGeofenceId());
-        Context.getGeofenceManager().refresh();
-        return Response.noContent().build();
-    }
-
-}
diff --git a/src/org/traccar/api/resource/GroupPermissionResource.java b/src/org/traccar/api/resource/GroupPermissionResource.java
deleted file mode 100644
index 61a725222..000000000
--- a/src/org/traccar/api/resource/GroupPermissionResource.java
+++ /dev/null
@@ -1,62 +0,0 @@
-/*
- * Copyright 2016 - 2017 Anton Tananaev (anton@traccar.org)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.traccar.api.resource;
-
-import org.traccar.Context;
-import org.traccar.api.BaseResource;
-import org.traccar.model.GroupPermission;
-
-import javax.ws.rs.Consumes;
-import javax.ws.rs.DELETE;
-import javax.ws.rs.POST;
-import javax.ws.rs.Path;
-import javax.ws.rs.Produces;
-import javax.ws.rs.core.MediaType;
-import javax.ws.rs.core.Response;
-import java.sql.SQLException;
-
-@Path("permissions/groups")
-@Produces(MediaType.APPLICATION_JSON)
-@Consumes(MediaType.APPLICATION_JSON)
-public class GroupPermissionResource extends BaseResource {
-
-    @POST
-    public Response add(GroupPermission entity) throws SQLException {
-        Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkUser(getUserId(), entity.getUserId());
-        Context.getPermissionsManager().checkGroup(getUserId(), entity.getGroupId());
-        Context.getDataManager().linkGroup(entity.getUserId(), entity.getGroupId());
-        Context.getPermissionsManager().refreshPermissions();
-        if (Context.getGeofenceManager() != null) {
-            Context.getGeofenceManager().refresh();
-        }
-        return Response.ok(entity).build();
-    }
-
-    @DELETE
-    public Response remove(GroupPermission entity) throws SQLException {
-        Context.getPermissionsManager().checkReadonly(getUserId());
-        Context.getPermissionsManager().checkUser(getUserId(), entity.getUserId());
-        Context.getPermissionsManager().checkGroup(getUserId(), entity.getGroupId());
-        Context.getDataManager().unlinkGroup(entity.getUserId(), entity.getGroupId());
-        Context.getPermissionsManager().refreshPermissions();
-        if (Context.getGeofenceManager() != null) {
-            Context.getGeofenceManager().refresh();
-        }
-        return Response.noContent().build();
-    }
-
-}
diff --git a/src/org/traccar/api/resource/GroupResource.java b/src/org/traccar/api/resource/GroupResource.java
index ceba69105..f20c95327 100644
--- a/src/org/traccar/api/resource/GroupResource.java
+++ b/src/org/traccar/api/resource/GroupResource.java
@@ -18,6 +18,7 @@ package org.traccar.api.resource;
 import org.traccar.Context;
 import org.traccar.api.BaseResource;
 import org.traccar.model.Group;
+import org.traccar.model.User;
 
 import javax.ws.rs.Consumes;
 import javax.ws.rs.DELETE;
@@ -61,11 +62,9 @@ public class GroupResource extends BaseResource {
     public Response add(Group entity) throws SQLException {
         Context.getPermissionsManager().checkReadonly(getUserId());
         Context.getDeviceManager().addGroup(entity);
-        Context.getDataManager().linkGroup(getUserId(), entity.getId());
+        Context.getDataManager().linkObject(User.class, getUserId(), entity.getClass(), entity.getId(), true);
         Context.getPermissionsManager().refreshPermissions();
-        if (Context.getGeofenceManager() != null) {
-            Context.getGeofenceManager().refresh();
-        }
+        Context.getPermissionsManager().refreshAllExtendedPermissions();
         return Response.ok(entity).build();
     }
 
@@ -75,9 +74,7 @@ public class GroupResource extends BaseResource {
         Context.getPermissionsManager().checkReadonly(getUserId());
         Context.getPermissionsManager().checkGroup(getUserId(), entity.getId());
         Context.getDeviceManager().updateGroup(entity);
-        if (Context.getGeofenceManager() != null) {
-            Context.getGeofenceManager().refresh();
-        }
+        Context.getPermissionsManager().refreshAllExtendedPermissions();
         return Response.ok(entity).build();
     }
 
@@ -88,9 +85,7 @@ public class GroupResource extends BaseResource {
         Context.getPermissionsManager().checkGroup(getUserId(), id);
         Context.getDeviceManager().removeGroup(id);
         Context.getPermissionsManager().refreshPermissions();
-        if (Context.getGeofenceManager() != null) {
-            Context.getGeofenceManager().refresh();
-        }
+        Context.getPermissionsManager().refreshAllExtendedPermissions();
         return Response.noContent().build();
     }
 
diff --git a/src/org/traccar/api/resource/PermissionsResource.java b/src/org/traccar/api/resource/PermissionsResource.java
new file mode 100644
index 000000000..9b9f65ad1
--- /dev/null
+++ b/src/org/traccar/api/resource/PermissionsResource.java
@@ -0,0 +1,79 @@
+/*
+ * Copyright 2017 Anton Tananaev (anton@traccar.org)
+ * Copyright 2017 Andrey Kunitsyn (andrey@traccar.org)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.traccar.api.resource;
+
+import java.sql.SQLException;
+import java.util.LinkedHashMap;
+
+import javax.ws.rs.Consumes;
+import javax.ws.rs.DELETE;
+import javax.ws.rs.POST;
+import javax.ws.rs.Path;
+import javax.ws.rs.Produces;
+import javax.ws.rs.core.MediaType;
+import javax.ws.rs.core.Response;
+
+import org.traccar.Context;
+import org.traccar.api.BaseResource;
+import org.traccar.model.Device;
+import org.traccar.model.Permission;
+import org.traccar.model.User;
+
+@Path("permissions")
+@Produces(MediaType.APPLICATION_JSON)
+@Consumes(MediaType.APPLICATION_JSON)
+public class PermissionsResource  extends BaseResource {
+
+    private void checkPermission(Permission permission, boolean link) {
+        if (!link && permission.getOwnerClass().equals(User.class)
+                && permission.getPropertyClass().equals(Device.class)) {
+            if (getUserId() != permission.getOwnerId()) {
+                Context.getPermissionsManager().checkUser(getUserId(), permission.getOwnerId());
+            } else {
+                Context.getPermissionsManager().checkAdmin(getUserId());
+            }
+        } else {
+            Context.getPermissionsManager().checkPermission(
+                    permission.getOwnerClass(), getUserId(), permission.getOwnerId());
+        }
+        Context.getPermissionsManager().checkPermission(
+                permission.getPropertyClass(), getUserId(), permission.getPropertyId());
+    }
+
+    @POST
+    public Response add(LinkedHashMap<String, Long> entity) throws SQLException, ClassNotFoundException {
+        Context.getPermissionsManager().checkReadonly(getUserId());
+        Permission permission = new Permission(entity);
+        checkPermission(permission, true);
+        Context.getDataManager().linkObject(permission.getOwnerClass(), permission.getOwnerId(),
+                permission.getPropertyClass(), permission.getPropertyId(), true);
+        Context.getPermissionsManager().refreshPermissions(permission);
+        return Response.noContent().build();
+    }
+
+    @DELETE
+    public Response remove(LinkedHashMap<String, Long> entity) throws SQLException, ClassNotFoundException {
+        Context.getPermissionsManager().checkReadonly(getUserId());
+        Permission permission = new Permission(entity);
+        checkPermission(permission, false);
+        Context.getDataManager().linkObject(permission.getOwnerClass(), permission.getOwnerId(),
+                permission.getPropertyClass(), permission.getPropertyId(), false);
+        Context.getPermissionsManager().refreshPermissions(permission);
+        return Response.noContent().build();
+    }
+
+}
diff --git a/src/org/traccar/api/resource/UserPermissionResource.java b/src/org/traccar/api/resource/UserPermissionResource.java
deleted file mode 100644
index a97c4a665..000000000
--- a/src/org/traccar/api/resource/UserPermissionResource.java
+++ /dev/null
@@ -1,56 +0,0 @@
-/*
- * Copyright 2017 Anton Tananaev (anton@traccar.org)
- * Copyright 2017 Andrey Kunitsyn (andrey@traccar.org)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.traccar.api.resource;
-
-import java.sql.SQLException;
-
-import javax.ws.rs.Consumes;
-import javax.ws.rs.DELETE;
-import javax.ws.rs.POST;
-import javax.ws.rs.Path;
-import javax.ws.rs.Produces;
-import javax.ws.rs.core.MediaType;
-import javax.ws.rs.core.Response;
-
-import org.traccar.Context;
-import org.traccar.api.BaseResource;
-import org.traccar.model.UserPermission;
-
-@Path("permissions/users")
-@Produces(MediaType.APPLICATION_JSON)
-@Consumes(MediaType.APPLICATION_JSON)
-public class UserPermissionResource extends BaseResource {
-
-    @POST
-    public Response add(UserPermission entity) throws SQLException {
-        Context.getPermissionsManager().checkAdmin(getUserId());
-        if (entity.getUserId() != entity.getManagedUserId()) {
-            Context.getDataManager().linkUser(entity.getUserId(), entity.getManagedUserId());
-            Context.getPermissionsManager().refreshUserPermissions();
-        }
-        return Response.ok(entity).build();
-    }
-
-    @DELETE
-    public Response remove(UserPermission entity) throws SQLException {
-        Context.getPermissionsManager().checkAdmin(getUserId());
-        Context.getDataManager().unlinkUser(entity.getUserId(), entity.getManagedUserId());
-        Context.getPermissionsManager().refreshUserPermissions();
-        return Response.noContent().build();
-    }
-
-}
diff --git a/src/org/traccar/api/resource/UserResource.java b/src/org/traccar/api/resource/UserResource.java
index 4d8a8b3a4..98395e3cc 100644
--- a/src/org/traccar/api/resource/UserResource.java
+++ b/src/org/traccar/api/resource/UserResource.java
@@ -17,6 +17,7 @@ package org.traccar.api.resource;
 
 import org.traccar.Context;
 import org.traccar.api.BaseResource;
+import org.traccar.model.ManagedUser;
 import org.traccar.model.User;
 
 import javax.annotation.security.PermitAll;
@@ -74,7 +75,7 @@ public class UserResource extends BaseResource {
         }
         Context.getPermissionsManager().addUser(entity);
         if (Context.getPermissionsManager().isManager(getUserId())) {
-            Context.getDataManager().linkUser(getUserId(), entity.getId());
+            Context.getDataManager().linkObject(User.class, getUserId(), ManagedUser.class, entity.getId(), true);
         }
         Context.getPermissionsManager().refreshUserPermissions();
         if (Context.getNotificationManager() != null) {
@@ -104,7 +105,7 @@ public class UserResource extends BaseResource {
         Context.getPermissionsManager().checkUser(getUserId(), id);
         Context.getPermissionsManager().removeUser(id);
         if (Context.getGeofenceManager() != null) {
-            Context.getGeofenceManager().refreshUserGeofences();
+            Context.getGeofenceManager().refreshUserItems();
         }
         if (Context.getNotificationManager() != null) {
             Context.getNotificationManager().refresh();
diff --git a/src/org/traccar/database/AttributesManager.java b/src/org/traccar/database/AttributesManager.java
index 362d6130f..266fc5526 100644
--- a/src/org/traccar/database/AttributesManager.java
+++ b/src/org/traccar/database/AttributesManager.java
@@ -17,183 +17,27 @@
 package org.traccar.database;
 
 import java.sql.SQLException;
-import java.util.Collection;
-import java.util.HashSet;
-import java.util.LinkedList;
-import java.util.Map;
-import java.util.Set;
-import java.util.concurrent.ConcurrentHashMap;
 
-import org.traccar.Context;
-import org.traccar.helper.Log;
-import org.traccar.model.AttributePermission;
 import org.traccar.model.Attribute;
-import org.traccar.model.Device;
-import org.traccar.model.DeviceAttribute;
-import org.traccar.model.GroupAttribute;
+import org.traccar.model.BaseModel;
 
-public class AttributesManager {
-
-    private final DataManager dataManager;
-
-    private final Map<Long, Attribute> attributes = new ConcurrentHashMap<>();
-    private final Map<Long, Set<Long>> deviceAttributes = new ConcurrentHashMap<>();
-    private final Map<Long, Set<Long>> deviceAttributesWithGroups = new ConcurrentHashMap<>();
-    private final Map<Long, Set<Long>> groupAttributes = new ConcurrentHashMap<>();
-    private final Map<Long, Set<Long>> userAttributes = new ConcurrentHashMap<>();
+public class AttributesManager extends ExtendedObjectManager {
 
     public AttributesManager(DataManager dataManager) {
-        this.dataManager = dataManager;
-        refreshAttributes();
-    }
-
-    public Set<Long> getUserAttributes(long userId) {
-        if (!userAttributes.containsKey(userId)) {
-            userAttributes.put(userId, new HashSet<Long>());
-        }
-        return userAttributes.get(userId);
-    }
-
-    public Set<Long> getGroupAttributes(long groupId) {
-        if (!groupAttributes.containsKey(groupId)) {
-            groupAttributes.put(groupId, new HashSet<Long>());
-        }
-        return groupAttributes.get(groupId);
-    }
-
-    public Set<Long> getDeviceAttributes(long deviceId) {
-        return getDeviceAttributes(deviceAttributes, deviceId);
-    }
-
-    public Set<Long> getAllDeviceAttributes(long deviceId) {
-        return getDeviceAttributes(deviceAttributesWithGroups, deviceId);
+        super(dataManager, Attribute.class);
+        refreshItems();
+        refreshExtendedPermissions();
     }
 
-    private Set<Long> getDeviceAttributes(Map<Long, Set<Long>> deviceAttributes, long deviceId) {
-        if (!deviceAttributes.containsKey(deviceId)) {
-            deviceAttributes.put(deviceId, new HashSet<Long>());
-        }
-        return deviceAttributes.get(deviceId);
-    }
-
-    public final void refreshAttributes() {
-        if (dataManager != null) {
-            try {
-                attributes.clear();
-                for (Attribute attribute : dataManager.getAttributes()) {
-                    attributes.put(attribute.getId(), attribute);
-                }
-            } catch (SQLException error) {
-                Log.warning(error);
-            }
-        }
-        refreshUserAttributes();
-        refresh();
-    }
-
-    public final void refreshUserAttributes() {
-        if (dataManager != null) {
-            try {
-                userAttributes.clear();
-                for (AttributePermission attributePermission : dataManager.getAttributePermissions()) {
-                    getUserAttributes(attributePermission.getUserId()).add(attributePermission.getAttributeId());
-                }
-            } catch (SQLException error) {
-                Log.warning(error);
-            }
-        }
-    }
-
-    public final void refresh() {
-        if (dataManager != null) {
-            try {
-
-                Collection<GroupAttribute> databaseGroupAttributes = dataManager.getGroupAttributes();
-
-                groupAttributes.clear();
-                for (GroupAttribute groupAttribute : databaseGroupAttributes) {
-                    getGroupAttributes(groupAttribute.getGroupId()).add(groupAttribute.getAttributeId());
-                }
-
-                Collection<DeviceAttribute> databaseDeviceAttributes = dataManager.getDeviceAttributes();
-                Collection<Device> allDevices = Context.getDeviceManager().getAllDevices();
-
-                deviceAttributes.clear();
-                deviceAttributesWithGroups.clear();
-
-                for (DeviceAttribute deviceAttribute : databaseDeviceAttributes) {
-                    getDeviceAttributes(deviceAttribute.getDeviceId())
-                        .add(deviceAttribute.getAttributeId());
-                    getAllDeviceAttributes(deviceAttribute.getDeviceId())
-                        .add(deviceAttribute.getAttributeId());
-                }
-
-                for (Device device : allDevices) {
-                    long groupId = device.getGroupId();
-                    while (groupId != 0) {
-                        getAllDeviceAttributes(device.getId()).addAll(getGroupAttributes(groupId));
-                        if (Context.getDeviceManager().getGroupById(groupId) != null) {
-                            groupId = Context.getDeviceManager().getGroupById(groupId).getGroupId();
-                        } else {
-                            groupId = 0;
-                        }
-                    }
-                }
-
-            } catch (SQLException error) {
-                Log.warning(error);
-            }
-        }
-    }
-
-    public void addAttribute(Attribute attribute) throws SQLException {
-        dataManager.addAttribute(attribute);
-        attributes.put(attribute.getId(), attribute);
-    }
-
-    public void updateAttribute(Attribute attribute) throws SQLException {
-        dataManager.updateAttribute(attribute);
-        Attribute cachedAttribute = attributes.get(attribute.getId());
+    @Override
+    public void updateItem(BaseModel item) throws SQLException {
+        Attribute attribute = (Attribute) item;
+        getDataManager().updateObject(attribute);
+        Attribute cachedAttribute = (Attribute) getById(item.getId());
         cachedAttribute.setDescription(attribute.getDescription());
         cachedAttribute.setAttribute(attribute.getAttribute());
         cachedAttribute.setExpression(attribute.getExpression());
         cachedAttribute.setType(attribute.getType());
     }
 
-    public void removeAttribute(long computedAttributeId) throws SQLException {
-        dataManager.removeAttribute(computedAttributeId);
-        attributes.remove(computedAttributeId);
-        refreshUserAttributes();
-        refresh();
-    }
-
-    public boolean checkAttribute(long userId, long attributeId) {
-        return getUserAttributes(userId).contains(attributeId);
-    }
-
-    public Attribute getAttribute(long id) {
-        return attributes.get(id);
-    }
-
-    public final Collection<Attribute> getAttributes(Set<Long> attributeIds) {
-        Collection<Attribute> result = new LinkedList<>();
-        for (long attributeId : attributeIds) {
-            result.add(getAttribute(attributeId));
-        }
-        return result;
-    }
-
-    public final Set<Long> getAllAttributes() {
-        return attributes.keySet();
-    }
-
-    public final Set<Long> getManagedAttributes(long userId) {
-        Set<Long> attributes = new HashSet<>();
-        attributes.addAll(getUserAttributes(userId));
-        for (long managedUserId : Context.getPermissionsManager().getUserPermissions(userId)) {
-            attributes.addAll(getUserAttributes(managedUserId));
-        }
-        return attributes;
-    }
-
 }
diff --git a/src/org/traccar/database/CalendarManager.java b/src/org/traccar/database/CalendarManager.java
index 31d484327..80bb79db2 100644
--- a/src/org/traccar/database/CalendarManager.java
+++ b/src/org/traccar/database/CalendarManager.java
@@ -16,107 +16,13 @@
  */
 package org.traccar.database;
 
-import java.sql.SQLException;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.HashSet;
-import java.util.Map;
-import java.util.Set;
-import java.util.concurrent.ConcurrentHashMap;
-
-import org.traccar.Context;
-import org.traccar.helper.Log;
 import org.traccar.model.Calendar;
-import org.traccar.model.CalendarPermission;
-
-public class CalendarManager {
-
-    private final DataManager dataManager;
 
-    private final Map<Long, Calendar> calendars = new ConcurrentHashMap<>();
-    private final Map<Long, Set<Long>> userCalendars = new ConcurrentHashMap<>();
+public class CalendarManager extends SimpleObjectManager {
 
     public CalendarManager(DataManager dataManager) {
-        this.dataManager = dataManager;
-        refreshCalendars();
-    }
-
-    public final void refreshCalendars() {
-        if (dataManager != null) {
-            try {
-                calendars.clear();
-                for (Calendar calendar : dataManager.getCalendars()) {
-                    calendars.put(calendar.getId(), calendar);
-                }
-            } catch (SQLException error) {
-                Log.warning(error);
-            }
-        }
-        refreshUserCalendars();
-    }
-
-    private Set<Long> getUserCalendarIds(long userId) {
-        if (!userCalendars.containsKey(userId)) {
-            userCalendars.put(userId, new HashSet<Long>());
-        }
-        return userCalendars.get(userId);
-    }
-
-    public Collection<Calendar> getUserCalendars(long userId) {
-        ArrayList<Calendar> result = new ArrayList<>();
-        for (long calendarId : getUserCalendarIds(userId)) {
-            result.add(calendars.get(calendarId));
-        }
-        return result;
-    }
-
-    public Collection<Calendar> getManagedCalendars(long userId) {
-        ArrayList<Calendar> result = new ArrayList<>();
-        result.addAll(getUserCalendars(userId));
-        for (long managedUserId : Context.getPermissionsManager().getUserPermissions(userId)) {
-            result.addAll(getUserCalendars(managedUserId));
-        }
-        return result;
-    }
-
-    public final void refreshUserCalendars() {
-        if (dataManager != null) {
-            try {
-                userCalendars.clear();
-                for (CalendarPermission calendarsPermission : dataManager.getCalendarPermissions()) {
-                    getUserCalendarIds(calendarsPermission.getUserId()).add(calendarsPermission.getCalendarId());
-                }
-            } catch (SQLException error) {
-                Log.warning(error);
-            }
-        }
-    }
-
-    public Calendar getCalendar(long calendarId) {
-        return calendars.get(calendarId);
-    }
-
-    public final void addCalendar(Calendar calendar) throws SQLException {
-        dataManager.addCalendar(calendar);
-        calendars.put(calendar.getId(), calendar);
-    }
-
-    public final void updateCalendar(Calendar calendar) throws SQLException {
-        dataManager.updateCalendar(calendar);
-        calendars.put(calendar.getId(), calendar);
-    }
-
-    public final void removeCalendar(long calendarId) throws SQLException {
-        dataManager.removeCalendar(calendarId);
-        calendars.remove(calendarId);
-        refreshUserCalendars();
+        super(dataManager, Calendar.class);
+        refreshItems();
     }
 
-    public Collection<Calendar> getAllCalendars() {
-        return calendars.values();
-    }
-
-    public boolean checkCalendar(long userId, long calendarId) {
-        return getUserCalendarIds(userId).contains(calendarId);
-    }
 }
diff --git a/src/org/traccar/database/DataManager.java b/src/org/traccar/database/DataManager.java
index 1c2a66bcf..80b9f98e9 100644
--- a/src/org/traccar/database/DataManager.java
+++ b/src/org/traccar/database/DataManager.java
@@ -23,6 +23,7 @@ import java.sql.SQLException;
 import java.text.SimpleDateFormat;
 import java.util.Collection;
 import java.util.Date;
+import java.util.Map;
 
 import javax.naming.InitialContext;
 import javax.sql.DataSource;
@@ -38,31 +39,13 @@ import liquibase.resource.ResourceAccessor;
 import org.traccar.Config;
 import org.traccar.helper.Log;
 import org.traccar.model.AttributeAlias;
-import org.traccar.model.AttributePermission;
-import org.traccar.model.Calendar;
-import org.traccar.model.CalendarPermission;
-import org.traccar.model.Attribute;
 import org.traccar.model.Device;
-import org.traccar.model.DeviceAttribute;
-import org.traccar.model.DeviceDriver;
-import org.traccar.model.DevicePermission;
-import org.traccar.model.Driver;
-import org.traccar.model.DriverPermission;
 import org.traccar.model.Event;
-import org.traccar.model.Geofence;
-import org.traccar.model.Group;
-import org.traccar.model.GroupAttribute;
-import org.traccar.model.GroupDriver;
-import org.traccar.model.GroupGeofence;
-import org.traccar.model.GroupPermission;
-import org.traccar.model.Notification;
+import org.traccar.model.BaseModel;
 import org.traccar.model.Position;
 import org.traccar.model.Server;
 import org.traccar.model.Statistics;
 import org.traccar.model.User;
-import org.traccar.model.UserPermission;
-import org.traccar.model.DeviceGeofence;
-import org.traccar.model.GeofencePermission;
 
 import com.zaxxer.hikari.HikariConfig;
 import com.zaxxer.hikari.HikariDataSource;
@@ -166,17 +149,6 @@ public class DataManager {
         }
     }
 
-    public Collection<User> getUsers() throws SQLException {
-        return QueryBuilder.create(dataSource, getQuery("database.selectUsersAll"))
-                .executeQuery(User.class);
-    }
-
-    public void addUser(User user) throws SQLException {
-        user.setId(QueryBuilder.create(dataSource, getQuery("database.insertUser"), true)
-                .setObject(user)
-                .executeUpdate());
-    }
-
     public void updateUser(User user) throws SQLException {
         QueryBuilder.create(dataSource, getQuery("database.updateUser"))
                 .setObject(user)
@@ -188,102 +160,12 @@ public class DataManager {
         }
     }
 
-    public void removeUser(long userId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.deleteUser"))
-                .setLong("id", userId)
-                .executeUpdate();
-    }
-
-    public Collection<DevicePermission> getDevicePermissions() throws SQLException {
-        return QueryBuilder.create(dataSource, getQuery("database.selectDevicePermissions"))
-                .executeQuery(DevicePermission.class);
-    }
-
-    public Collection<GroupPermission> getGroupPermissions() throws SQLException {
-        return QueryBuilder.create(dataSource, getQuery("database.selectGroupPermissions"))
-                .executeQuery(GroupPermission.class);
-    }
-
-    public Collection<Device> getAllDevices() throws SQLException {
-        return QueryBuilder.create(dataSource, getQuery("database.selectDevicesAll"))
-                .executeQuery(Device.class);
-    }
-
-    public void addDevice(Device device) throws SQLException {
-        device.setId(QueryBuilder.create(dataSource, getQuery("database.insertDevice"), true)
-                .setObject(device)
-                .executeUpdate());
-    }
-
-    public void updateDevice(Device device) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.updateDevice"))
-                .setObject(device)
-                .executeUpdate();
-    }
-
     public void updateDeviceStatus(Device device) throws SQLException {
         QueryBuilder.create(dataSource, getQuery("database.updateDeviceStatus"))
                 .setObject(device)
                 .executeUpdate();
     }
 
-    public void removeDevice(long deviceId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.deleteDevice"))
-                .setLong("id", deviceId)
-                .executeUpdate();
-    }
-
-    public void linkDevice(long userId, long deviceId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.linkDevice"))
-                .setLong("userId", userId)
-                .setLong("deviceId", deviceId)
-                .executeUpdate();
-    }
-
-    public void unlinkDevice(long userId, long deviceId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.unlinkDevice"))
-                .setLong("userId", userId)
-                .setLong("deviceId", deviceId)
-                .executeUpdate();
-    }
-
-    public Collection<Group> getAllGroups() throws SQLException {
-        return QueryBuilder.create(dataSource, getQuery("database.selectGroupsAll"))
-                .executeQuery(Group.class);
-    }
-
-    public void addGroup(Group group) throws SQLException {
-        group.setId(QueryBuilder.create(dataSource, getQuery("database.insertGroup"), true)
-                .setObject(group)
-                .executeUpdate());
-    }
-
-    public void updateGroup(Group group) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.updateGroup"))
-                .setObject(group)
-                .executeUpdate();
-    }
-
-    public void removeGroup(long groupId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.deleteGroup"))
-                .setLong("id", groupId)
-                .executeUpdate();
-    }
-
-    public void linkGroup(long userId, long groupId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.linkGroup"))
-                .setLong("userId", userId)
-                .setLong("groupId", groupId)
-                .executeUpdate();
-    }
-
-    public void unlinkGroup(long userId, long groupId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.unlinkGroup"))
-                .setLong("userId", userId)
-                .setLong("groupId", groupId)
-                .executeUpdate();
-    }
-
     public Collection<Position> getPositions(long deviceId, Date from, Date to) throws SQLException {
         return QueryBuilder.create(dataSource, getQuery("database.selectPositions"))
                 .setLong("deviceId", deviceId)
@@ -336,24 +218,12 @@ public class DataManager {
                 .executeQuerySingle(Server.class);
     }
 
-    public void updateServer(Server server) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.updateServer"))
-                .setObject(server)
-                .executeUpdate();
-    }
-
     public Event getEvent(long eventId) throws SQLException {
         return QueryBuilder.create(dataSource, getQuery("database.selectEvent"))
                 .setLong("id", eventId)
                 .executeQuerySingle(Event.class);
     }
 
-    public void addEvent(Event event) throws SQLException {
-        event.setId(QueryBuilder.create(dataSource, getQuery("database.insertEvent"), true)
-                .setObject(event)
-                .executeUpdate());
-    }
-
     public Collection<Event> getEvents(long deviceId, Date from, Date to) throws SQLException {
         return QueryBuilder.create(dataSource, getQuery("database.selectEvents"))
                 .setLong("deviceId", deviceId)
@@ -362,109 +232,6 @@ public class DataManager {
                 .executeQuery(Event.class);
     }
 
-    public Collection<Geofence> getGeofences() throws SQLException {
-        return QueryBuilder.create(dataSource, getQuery("database.selectGeofencesAll"))
-                .executeQuery(Geofence.class);
-    }
-
-    public void addGeofence(Geofence geofence) throws SQLException {
-        geofence.setId(QueryBuilder.create(dataSource, getQuery("database.insertGeofence"), true)
-                .setObject(geofence)
-                .executeUpdate());
-    }
-
-    public void updateGeofence(Geofence geofence) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.updateGeofence"))
-                .setObject(geofence)
-                .executeUpdate();
-    }
-
-    public void removeGeofence(long geofenceId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.deleteGeofence"))
-                .setLong("id", geofenceId)
-                .executeUpdate();
-    }
-
-    public Collection<GeofencePermission> getGeofencePermissions() throws SQLException {
-        return QueryBuilder.create(dataSource, getQuery("database.selectGeofencePermissions"))
-                .executeQuery(GeofencePermission.class);
-    }
-
-    public void linkGeofence(long userId, long geofenceId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.linkGeofence"))
-                .setLong("userId", userId)
-                .setLong("geofenceId", geofenceId)
-                .executeUpdate();
-    }
-
-    public void unlinkGeofence(long userId, long geofenceId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.unlinkGeofence"))
-                .setLong("userId", userId)
-                .setLong("geofenceId", geofenceId)
-                .executeUpdate();
-    }
-
-    public Collection<GroupGeofence> getGroupGeofences() throws SQLException {
-        return QueryBuilder.create(dataSource, getQuery("database.selectGroupGeofences"))
-                .executeQuery(GroupGeofence.class);
-    }
-
-    public void linkGroupGeofence(long groupId, long geofenceId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.linkGroupGeofence"))
-                .setLong("groupId", groupId)
-                .setLong("geofenceId", geofenceId)
-                .executeUpdate();
-    }
-
-    public void unlinkGroupGeofence(long groupId, long geofenceId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.unlinkGroupGeofence"))
-                .setLong("groupId", groupId)
-                .setLong("geofenceId", geofenceId)
-                .executeUpdate();
-    }
-
-    public Collection<DeviceGeofence> getDeviceGeofences() throws SQLException {
-        return QueryBuilder.create(dataSource, getQuery("database.selectDeviceGeofences"))
-                .executeQuery(DeviceGeofence.class);
-    }
-
-    public void linkDeviceGeofence(long deviceId, long geofenceId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.linkDeviceGeofence"))
-                .setLong("deviceId", deviceId)
-                .setLong("geofenceId", geofenceId)
-                .executeUpdate();
-    }
-
-    public void unlinkDeviceGeofence(long deviceId, long geofenceId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.unlinkDeviceGeofence"))
-                .setLong("deviceId", deviceId)
-                .setLong("geofenceId", geofenceId)
-                .executeUpdate();
-    }
-
-    public Collection<Notification> getNotifications() throws SQLException {
-        return QueryBuilder.create(dataSource, getQuery("database.selectNotifications"))
-                .executeQuery(Notification.class);
-    }
-
-    public void addNotification(Notification notification) throws SQLException {
-        notification.setId(QueryBuilder.create(dataSource, getQuery("database.insertNotification"), true)
-                .setObject(notification)
-                .executeUpdate());
-    }
-
-    public void updateNotification(Notification notification) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.updateNotification"))
-                .setObject(notification)
-                .executeUpdate();
-    }
-
-    public void removeNotification(Notification notification) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.deleteNotification"))
-                .setLong("id", notification.getId())
-                .executeUpdate();
-    }
-
     public Collection<AttributeAlias> getAttributeAliases() throws SQLException {
         return QueryBuilder.create(dataSource, getQuery("database.selectAttributeAliases"))
                 .executeQuery(AttributeAlias.class);
@@ -501,224 +268,55 @@ public class DataManager {
                 .executeUpdate());
     }
 
-    public Collection<Calendar> getCalendars() throws SQLException {
-        return QueryBuilder.create(dataSource, getQuery("database.selectCalendarsAll"))
-                .executeQuery(Calendar.class);
+    public static Class<?> getClassByName(String name) throws ClassNotFoundException {
+        return Class.forName("org.traccar.model."
+                + name.substring(0, 1).toUpperCase() + name.replace("Id", "").substring(1));
     }
 
-    public void addCalendar(Calendar calendar) throws SQLException {
-        calendar.setId(QueryBuilder.create(dataSource, getQuery("database.insertCalendar"), true)
-                .setObject(calendar)
-                .executeUpdate());
-    }
-
-    public void updateCalendar(Calendar calendar) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.updateCalendar"))
-                .setObject(calendar)
-                .executeUpdate();
-    }
-
-    public void removeCalendar(long calendarId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.deleteCalendar"))
-                .setLong("id", calendarId)
-                .executeUpdate();
+    public static String makeNameId(Class<?> clazz) {
+        String name = clazz.getSimpleName();
+        return name.substring(0, 1).toLowerCase() + name.substring(1) + (name.indexOf("Id") == -1 ? "Id" : "");
     }
 
-    public Collection<CalendarPermission> getCalendarPermissions() throws SQLException {
-        return QueryBuilder.create(dataSource, getQuery("database.selectCalendarPermissions"))
-                .executeQuery(CalendarPermission.class);
-    }
+    public void linkObject(Class<?> owner, long ownerId, Class<?> property, long propertyId, boolean link)
+            throws SQLException {
+        String query = "database." + (link ? "link" : "unlink") + owner.getSimpleName() + property.getSimpleName();
+        QueryBuilder queryBuilder = QueryBuilder.create(dataSource, getQuery(query));
 
-    public void linkCalendar(long userId, long calendarId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.linkCalendar"))
-                .setLong("userId", userId)
-                .setLong("calendarId", calendarId)
-                .executeUpdate();
+        queryBuilder.setLong(makeNameId(owner), ownerId);
+        queryBuilder.setLong(makeNameId(property), propertyId);
+        queryBuilder.executeUpdate();
     }
 
-    public void unlinkCalendar(long userId, long calendarId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.unlinkCalendar"))
-                .setLong("userId", userId)
-                .setLong("calendarId", calendarId)
-                .executeUpdate();
+    public <T> Collection<T> getObjects(Class<T> clazz) throws SQLException {
+        String query = "database.select" + clazz.getSimpleName() + "s";
+        return QueryBuilder.create(dataSource, getQuery(query)).executeQuery(clazz);
     }
 
-    public Collection<UserPermission> getUserPermissions() throws SQLException {
-        return QueryBuilder.create(dataSource, getQuery("database.selectUserPermissions"))
-                .executeQuery(UserPermission.class);
+    public Collection<Map<String, Long>> getPermissions(Class<? extends BaseModel> owner,
+            Class<? extends BaseModel> property) throws SQLException {
+        String query = "database.select" + owner.getSimpleName() + property.getSimpleName() + "s";
+        return QueryBuilder.create(dataSource, getQuery(query)).executeMapQuery(Long.class);
     }
 
-    public void linkUser(long userId, long managedUserId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.linkUser"))
-                .setLong("userId", userId)
-                .setLong("managedUserId", managedUserId)
-                .executeUpdate();
-    }
-
-    public void unlinkUser(long userId, long managedUserId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.unlinkUser"))
-                .setLong("userId", userId)
-                .setLong("managedUserId", managedUserId)
-                .executeUpdate();
-    }
-
-    public Collection<Attribute> getAttributes() throws SQLException {
-        return QueryBuilder.create(dataSource, getQuery("database.selectAttributes"))
-                .executeQuery(Attribute.class);
-    }
-
-    public void addAttribute(Attribute attribute) throws SQLException {
-        attribute.setId(QueryBuilder.create(dataSource, getQuery("database.insertAttribute"), true)
-                .setObject(attribute)
+    public void addObject(BaseModel entity) throws SQLException {
+        String query = "database.insert" + entity.getClass().getSimpleName();
+        entity.setId(QueryBuilder.create(dataSource, getQuery(query), true)
+                .setObject(entity)
                 .executeUpdate());
     }
 
-    public void updateAttribute(Attribute attribute) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.updateAttribute"))
-                .setObject(attribute)
+    public void updateObject(BaseModel entity) throws SQLException {
+        String query = "database.update" + entity.getClass().getSimpleName();
+        QueryBuilder.create(dataSource, getQuery(query))
+                .setObject(entity)
                 .executeUpdate();
     }
 
-    public void removeAttribute(long computedAttributeId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.deleteAttribute"))
-                .setLong("id", computedAttributeId)
-                .executeUpdate();
-    }
-
-    public Collection<AttributePermission> getAttributePermissions() throws SQLException {
-        return QueryBuilder.create(dataSource, getQuery("database.selectAttributePermissions"))
-                .executeQuery(AttributePermission.class);
-    }
-
-    public void linkAttribute(long userId, long attributeId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.linkAttribute"))
-                .setLong("userId", userId)
-                .setLong("attributeId", attributeId)
-                .executeUpdate();
-    }
-
-    public void unlinkAttribute(long userId, long attributeId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.unlinkAttribute"))
-                .setLong("userId", userId)
-                .setLong("attributeId", attributeId)
-                .executeUpdate();
-    }
-
-    public Collection<GroupAttribute> getGroupAttributes() throws SQLException {
-        return QueryBuilder.create(dataSource, getQuery("database.selectGroupAttributes"))
-                .executeQuery(GroupAttribute.class);
-    }
-
-    public void linkGroupAttribute(long groupId, long attributeId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.linkGroupAttribute"))
-                .setLong("groupId", groupId)
-                .setLong("attributeId", attributeId)
-                .executeUpdate();
-    }
-
-    public void unlinkGroupAttribute(long groupId, long attributeId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.unlinkGroupAttribute"))
-                .setLong("groupId", groupId)
-                .setLong("attributeId", attributeId)
-                .executeUpdate();
-    }
-
-    public Collection<DeviceAttribute> getDeviceAttributes() throws SQLException {
-        return QueryBuilder.create(dataSource, getQuery("database.selectDeviceAttributes"))
-                .executeQuery(DeviceAttribute.class);
-    }
-
-    public void linkDeviceAttribute(long deviceId, long attributeId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.linkDeviceAttribute"))
-                .setLong("deviceId", deviceId)
-                .setLong("attributeId", attributeId)
-                .executeUpdate();
-    }
-
-    public void unlinkDeviceAttribute(long deviceId, long attributeId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.unlinkDeviceAttribute"))
-                .setLong("deviceId", deviceId)
-                .setLong("attributeId", attributeId)
-                .executeUpdate();
-    }
-
-    public Collection<Driver> getDrivers() throws SQLException {
-        return QueryBuilder.create(dataSource, getQuery("database.selectDrivers"))
-                .executeQuery(Driver.class);
-    }
-
-    public void addDriver(Driver driver) throws SQLException {
-        driver.setId(QueryBuilder.create(dataSource, getQuery("database.insertDriver"), true)
-                .setObject(driver)
-                .executeUpdate());
-    }
-
-    public void updateDriver(Driver driver) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.updateDriver"))
-                .setObject(driver)
-                .executeUpdate();
-    }
-
-    public void removeDriver(long driverId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.deleteDriver"))
-                .setLong("id", driverId)
-                .executeUpdate();
-    }
-
-    public Collection<DriverPermission> getDriverPermissions() throws SQLException {
-        return QueryBuilder.create(dataSource, getQuery("database.selectDriverPermissions"))
-                .executeQuery(DriverPermission.class);
-    }
-
-    public void linkDriver(long userId, long driverId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.linkDriver"))
-                .setLong("userId", userId)
-                .setLong("driverId", driverId)
-                .executeUpdate();
-    }
-
-    public void unlinkDriver(long userId, long driverId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.unlinkDriver"))
-                .setLong("userId", userId)
-                .setLong("driverId", driverId)
-                .executeUpdate();
-    }
-
-    public Collection<GroupDriver> getGroupDrivers() throws SQLException {
-        return QueryBuilder.create(dataSource, getQuery("database.selectGroupDrivers"))
-                .executeQuery(GroupDriver.class);
-    }
-
-    public void linkGroupDriver(long groupId, long driverId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.linkGroupDriver"))
-                .setLong("groupId", groupId)
-                .setLong("driverId", driverId)
-                .executeUpdate();
-    }
-
-    public void unlinkGroupDriver(long groupId, long driverId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.unlinkGroupDriver"))
-                .setLong("groupId", groupId)
-                .setLong("driverId", driverId)
-                .executeUpdate();
-    }
-
-    public Collection<DeviceDriver> getDeviceDrivers() throws SQLException {
-        return QueryBuilder.create(dataSource, getQuery("database.selectDeviceDrivers"))
-                .executeQuery(DeviceDriver.class);
-    }
-
-    public void linkDeviceDriver(long deviceId, long driverId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.linkDeviceDriver"))
-                .setLong("deviceId", deviceId)
-                .setLong("driverId", driverId)
-                .executeUpdate();
-    }
-
-    public void unlinkDeviceDriver(long deviceId, long driverId) throws SQLException {
-        QueryBuilder.create(dataSource, getQuery("database.unlinkDeviceDriver"))
-                .setLong("deviceId", deviceId)
-                .setLong("driverId", driverId)
+    public void removeObject(Class<? extends BaseModel> clazz, long entityId) throws SQLException {
+        String query = "database.delete" + clazz.getSimpleName();
+        QueryBuilder.create(dataSource, getQuery(query))
+                .setLong("id", entityId)
                 .executeUpdate();
     }
 
diff --git a/src/org/traccar/database/DeviceManager.java b/src/org/traccar/database/DeviceManager.java
index f2a2dd565..ba360f165 100644
--- a/src/org/traccar/database/DeviceManager.java
+++ b/src/org/traccar/database/DeviceManager.java
@@ -85,7 +85,7 @@ public class DeviceManager implements IdentityManager {
         if ((force || System.currentTimeMillis() - lastUpdate > dataRefreshDelay)
                 && devicesLastUpdate.compareAndSet(lastUpdate, System.currentTimeMillis())) {
             GeofenceManager geofenceManager = Context.getGeofenceManager();
-            Collection<Device> databaseDevices = dataManager.getAllDevices();
+            Collection<Device> databaseDevices = dataManager.getObjects(Device.class);
             if (devicesById == null) {
                 devicesById = new ConcurrentHashMap<>(databaseDevices.size());
             }
@@ -199,7 +199,7 @@ public class DeviceManager implements IdentityManager {
     }
 
     public void addDevice(Device device) throws SQLException {
-        dataManager.addDevice(device);
+        dataManager.addObject(device);
 
         devicesById.put(device.getId(), device);
         devicesByUniqueId.put(device.getUniqueId(), device);
@@ -209,7 +209,7 @@ public class DeviceManager implements IdentityManager {
     }
 
     public void updateDevice(Device device) throws SQLException {
-        dataManager.updateDevice(device);
+        dataManager.updateObject(device);
 
         devicesById.put(device.getId(), device);
         devicesByUniqueId.put(device.getUniqueId(), device);
@@ -227,7 +227,7 @@ public class DeviceManager implements IdentityManager {
     }
 
     public void removeDevice(long deviceId) throws SQLException {
-        dataManager.removeDevice(deviceId);
+        dataManager.removeObject(Device.class, deviceId);
 
         if (devicesById.containsKey(deviceId)) {
             String deviceUniqueId = devicesById.get(deviceId).getUniqueId();
@@ -289,7 +289,7 @@ public class DeviceManager implements IdentityManager {
         long lastUpdate = groupsLastUpdate.get();
         if ((force || System.currentTimeMillis() - lastUpdate > dataRefreshDelay)
                 && groupsLastUpdate.compareAndSet(lastUpdate, System.currentTimeMillis())) {
-            Collection<Group> databaseGroups = dataManager.getAllGroups();
+            Collection<Group> databaseGroups = dataManager.getObjects(Group.class);
             if (groupsById == null) {
                 groupsById = new ConcurrentHashMap<>(databaseGroups.size());
             }
@@ -359,18 +359,18 @@ public class DeviceManager implements IdentityManager {
 
     public void addGroup(Group group) throws SQLException {
         checkGroupCycles(group);
-        dataManager.addGroup(group);
+        dataManager.addObject(group);
         groupsById.put(group.getId(), group);
     }
 
     public void updateGroup(Group group) throws SQLException {
         checkGroupCycles(group);
-        dataManager.updateGroup(group);
+        dataManager.updateObject(group);
         groupsById.put(group.getId(), group);
     }
 
     public void removeGroup(long groupId) throws SQLException {
-        dataManager.removeGroup(groupId);
+        dataManager.removeObject(Group.class, groupId);
         groupsById.remove(groupId);
     }
 
diff --git a/src/org/traccar/database/DriversManager.java b/src/org/traccar/database/DriversManager.java
index e89d59311..0dc2b102d 100644
--- a/src/org/traccar/database/DriversManager.java
+++ b/src/org/traccar/database/DriversManager.java
@@ -17,147 +17,50 @@
 package org.traccar.database;
 
 import java.sql.SQLException;
-import java.util.Collection;
-import java.util.HashSet;
-import java.util.LinkedList;
 import java.util.Map;
-import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 
-import org.traccar.Context;
 import org.traccar.helper.Log;
-import org.traccar.model.Device;
-import org.traccar.model.DeviceDriver;
 import org.traccar.model.Driver;
-import org.traccar.model.DriverPermission;
-import org.traccar.model.GroupDriver;
+import org.traccar.model.BaseModel;
 
-public class DriversManager {
+public class DriversManager extends ExtendedObjectManager {
 
-    private final DataManager dataManager;
-
-    private final Map<Long, Driver> drivers = new ConcurrentHashMap<>();
     private final Map<String, Driver> driversByUniqueId = new ConcurrentHashMap<>();
-    private final Map<Long, Set<Long>> deviceDrivers = new ConcurrentHashMap<>();
-    private final Map<Long, Set<Long>> deviceDriversWithGroups = new ConcurrentHashMap<>();
-    private final Map<Long, Set<Long>> groupDrivers = new ConcurrentHashMap<>();
-    private final Map<Long, Set<Long>> userDrivers = new ConcurrentHashMap<>();
 
     public DriversManager(DataManager dataManager) {
-        this.dataManager = dataManager;
-        refreshDrivers();
-    }
-
-    public Set<Long> getUserDrivers(long userId) {
-        if (!userDrivers.containsKey(userId)) {
-            userDrivers.put(userId, new HashSet<Long>());
-        }
-        return userDrivers.get(userId);
-    }
-
-    public Set<Long> getGroupDrivers(long groupId) {
-        if (!groupDrivers.containsKey(groupId)) {
-            groupDrivers.put(groupId, new HashSet<Long>());
-        }
-        return groupDrivers.get(groupId);
-    }
-
-    public Set<Long> getDeviceDrivers(long deviceId) {
-        return getDeviceDrivers(deviceDrivers, deviceId);
-    }
-
-    public Set<Long> getAllDeviceDrivers(long deviceId) {
-        return getDeviceDrivers(deviceDriversWithGroups, deviceId);
-    }
-
-    private Set<Long> getDeviceDrivers(Map<Long, Set<Long>> deviceDrivers, long deviceId) {
-        if (!deviceDrivers.containsKey(deviceId)) {
-            deviceDrivers.put(deviceId, new HashSet<Long>());
-        }
-        return deviceDrivers.get(deviceId);
+        super(dataManager, Driver.class);
+        refreshItems();
+        refreshExtendedPermissions();
     }
 
-    public final void refreshDrivers() {
-        if (dataManager != null) {
+    @Override
+    public void refreshItems() {
+        if (getDataManager() != null) {
             try {
-                drivers.clear();
-                driversByUniqueId.clear();
-                for (Driver driver : dataManager.getDrivers()) {
-                    drivers.put(driver.getId(), driver);
-                    driversByUniqueId.put(driver.getUniqueId(), driver);
+                clearItems();
+                for (BaseModel item : getDataManager().getObjects(getBaseClass())) {
+                    putItem(item.getId(), item);
+                    driversByUniqueId.put(((Driver) item).getUniqueId(), (Driver) item);
                 }
             } catch (SQLException error) {
                 Log.warning(error);
             }
         }
-        refreshUserDrivers();
-        refresh();
+        refreshUserItems();
     }
 
-    public final void refreshUserDrivers() {
-        if (dataManager != null) {
-            try {
-                userDrivers.clear();
-                for (DriverPermission driverPermission : dataManager.getDriverPermissions()) {
-                    getUserDrivers(driverPermission.getUserId()).add(driverPermission.getDriverId());
-                }
-            } catch (SQLException error) {
-                Log.warning(error);
-            }
-        }
+    @Override
+    public void addItem(BaseModel item) throws SQLException {
+        super.addItem(item);
+        driversByUniqueId.put(((Driver) item).getUniqueId(), (Driver) item);
     }
 
-    public final void refresh() {
-        if (dataManager != null) {
-            try {
-
-                Collection<GroupDriver> databaseGroupDrivers = dataManager.getGroupDrivers();
-
-                groupDrivers.clear();
-                for (GroupDriver groupDriver : databaseGroupDrivers) {
-                    getGroupDrivers(groupDriver.getGroupId()).add(groupDriver.getDriverId());
-                }
-
-                Collection<DeviceDriver> databaseDeviceDrivers = dataManager.getDeviceDrivers();
-                Collection<Device> allDevices = Context.getDeviceManager().getAllDevices();
-
-                deviceDrivers.clear();
-                deviceDriversWithGroups.clear();
-
-                for (DeviceDriver deviceAttribute : databaseDeviceDrivers) {
-                    getDeviceDrivers(deviceAttribute.getDeviceId())
-                        .add(deviceAttribute.getDriverId());
-                    getAllDeviceDrivers(deviceAttribute.getDeviceId())
-                        .add(deviceAttribute.getDriverId());
-                }
-
-                for (Device device : allDevices) {
-                    long groupId = device.getGroupId();
-                    while (groupId != 0) {
-                        getAllDeviceDrivers(device.getId()).addAll(getGroupDrivers(groupId));
-                        if (Context.getDeviceManager().getGroupById(groupId) != null) {
-                            groupId = Context.getDeviceManager().getGroupById(groupId).getGroupId();
-                        } else {
-                            groupId = 0;
-                        }
-                    }
-                }
-
-            } catch (SQLException error) {
-                Log.warning(error);
-            }
-        }
-    }
-
-    public void addDriver(Driver driver) throws SQLException {
-        dataManager.addDriver(driver);
-        drivers.put(driver.getId(), driver);
-        driversByUniqueId.put(driver.getUniqueId(), driver);
-    }
-
-    public void updateDriver(Driver driver) throws SQLException {
-        dataManager.updateDriver(driver);
-        Driver cachedDriver = drivers.get(driver.getId());
+    @Override
+    public void updateItem(BaseModel item) throws SQLException {
+        Driver driver = (Driver) item;
+        getDataManager().updateObject(driver);
+        Driver cachedDriver = (Driver) getById(driver.getId());
         cachedDriver.setName(driver.getName());
         if (!driver.getUniqueId().equals(cachedDriver.getUniqueId())) {
             driversByUniqueId.remove(cachedDriver.getUniqueId());
@@ -167,47 +70,20 @@ public class DriversManager {
         cachedDriver.setAttributes(driver.getAttributes());
     }
 
-    public void removeDriver(long driverId) throws SQLException {
-        dataManager.removeDriver(driverId);
-        if (drivers.containsKey(driverId)) {
-            String driverUniqueId = drivers.get(driverId).getUniqueId();
-            drivers.remove(driverId);
+    @Override
+    public void removeItem(long driverId) throws SQLException {
+        Driver cachedDriver = (Driver) getById(driverId);
+        getDataManager().removeObject(Driver.class, driverId);
+        if (cachedDriver != null) {
+            String driverUniqueId = cachedDriver.getUniqueId();
+            removeCachedItem(driverId);
             driversByUniqueId.remove(driverUniqueId);
         }
-        refreshUserDrivers();
-        refresh();
-    }
-
-    public boolean checkDriver(long userId, long driverId) {
-        return getUserDrivers(userId).contains(driverId);
-    }
-
-    public Driver getDriver(long id) {
-        return drivers.get(id);
+        refreshUserItems();
+        refreshExtendedPermissions();
     }
 
     public Driver getDriverByUniqueId(String uniqueId) {
         return driversByUniqueId.get(uniqueId);
     }
-
-    public final Collection<Driver> getDrivers(Set<Long> driverIds) {
-        Collection<Driver> result = new LinkedList<>();
-        for (long driverId : driverIds) {
-            result.add(getDriver(driverId));
-        }
-        return result;
-    }
-
-    public final Set<Long> getAllDrivers() {
-        return drivers.keySet();
-    }
-
-    public final Set<Long> getManagedDrivers(long userId) {
-        Set<Long> drivers = new HashSet<>();
-        drivers.addAll(getUserDrivers(userId));
-        for (long managedUserId : Context.getPermissionsManager().getUserPermissions(userId)) {
-            drivers.addAll(getUserDrivers(managedUserId));
-        }
-        return drivers;
-    }
 }
diff --git a/src/org/traccar/database/ExtendedObjectManager.java b/src/org/traccar/database/ExtendedObjectManager.java
new file mode 100644
index 000000000..483c3a09e
--- /dev/null
+++ b/src/org/traccar/database/ExtendedObjectManager.java
@@ -0,0 +1,121 @@
+/*
+ * Copyright 2017 Anton Tananaev (anton@traccar.org)
+ * Copyright 2017 Andrey Kunitsyn (andrey@traccar.org)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.traccar.database;
+
+import java.sql.SQLException;
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+
+import org.traccar.Context;
+import org.traccar.helper.Log;
+import org.traccar.model.Device;
+import org.traccar.model.Group;
+import org.traccar.model.BaseModel;
+
+public abstract class ExtendedObjectManager extends SimpleObjectManager {
+
+    private final Map<Long, Set<Long>> deviceItems = new ConcurrentHashMap<>();
+    private final Map<Long, Set<Long>> deviceItemsWithGroups = new ConcurrentHashMap<>();
+    private final Map<Long, Set<Long>> groupItems = new ConcurrentHashMap<>();
+
+    protected ExtendedObjectManager(DataManager dataManager, Class<? extends BaseModel> baseClass) {
+        super(dataManager, baseClass);
+    }
+
+    public final Set<Long> getGroupItems(long groupId) {
+        if (!groupItems.containsKey(groupId)) {
+            groupItems.put(groupId, new HashSet<Long>());
+        }
+        return groupItems.get(groupId);
+    }
+
+    protected final void clearGroupItems() {
+        groupItems.clear();
+    }
+
+    public final Set<Long> getDeviceItems(long deviceId) {
+        if (!deviceItems.containsKey(deviceId)) {
+            deviceItems.put(deviceId, new HashSet<Long>());
+        }
+        return deviceItems.get(deviceId);
+    }
+
+    protected final void clearDeviceItems() {
+        deviceItems.clear();
+    }
+
+    public Set<Long> getAllDeviceItems(long deviceId) {
+        if (!deviceItemsWithGroups.containsKey(deviceId)) {
+            deviceItemsWithGroups.put(deviceId, new HashSet<Long>());
+        }
+        return deviceItemsWithGroups.get(deviceId);
+    }
+
+    @Override
+    public void removeItem(long itemId) throws SQLException {
+        super.removeItem(itemId);
+        refreshExtendedPermissions();
+    }
+
+    public void refreshExtendedPermissions() {
+        if (getDataManager() != null) {
+            try {
+
+                Collection<Map<String, Long>> databaseGroupPermissions =
+                        getDataManager().getPermissions(Group.class, getBaseClass());
+
+                clearGroupItems();
+                for (Map<String, Long> groupPermission : databaseGroupPermissions) {
+                    getGroupItems(groupPermission.get(DataManager.makeNameId(Group.class)))
+                            .add(groupPermission.get(getBaseClassIdName()));
+                }
+
+                Collection<Map<String, Long>> databaseDevicePermissions =
+                        getDataManager().getPermissions(Device.class, getBaseClass());
+                Collection<Device> allDevices = Context.getDeviceManager().getAllDevices();
+
+                clearDeviceItems();
+                deviceItemsWithGroups.clear();
+
+                for (Map<String, Long> devicePermission : databaseDevicePermissions) {
+                    getDeviceItems(devicePermission.get(DataManager.makeNameId(Device.class)))
+                            .add(devicePermission.get(getBaseClassIdName()));
+                    getAllDeviceItems(devicePermission.get(DataManager.makeNameId(Device.class)))
+                            .add(devicePermission.get(getBaseClassIdName()));
+                }
+
+                for (Device device : allDevices) {
+                    long groupId = device.getGroupId();
+                    while (groupId != 0) {
+                        getAllDeviceItems(device.getId()).addAll(getGroupItems(groupId));
+                        if (Context.getDeviceManager().getGroupById(groupId) != null) {
+                            groupId = Context.getDeviceManager().getGroupById(groupId).getGroupId();
+                        } else {
+                            groupId = 0;
+                        }
+                    }
+                }
+
+            } catch (SQLException error) {
+                Log.warning(error);
+            }
+        }
+    }
+}
diff --git a/src/org/traccar/database/GeofenceManager.java b/src/org/traccar/database/GeofenceManager.java
index b8e6a5d73..bc2c27a65 100644
--- a/src/org/traccar/database/GeofenceManager.java
+++ b/src/org/traccar/database/GeofenceManager.java
@@ -15,290 +15,54 @@
  */
 package org.traccar.database;
 
-import java.sql.SQLException;
 import java.util.ArrayList;
-import java.util.Collection;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.LinkedList;
 import java.util.List;
-import java.util.Map;
-import java.util.Set;
-import java.util.concurrent.locks.ReadWriteLock;
-import java.util.concurrent.locks.ReentrantReadWriteLock;
 
 import org.traccar.Context;
-import org.traccar.helper.Log;
 import org.traccar.model.Device;
-import org.traccar.model.DeviceGeofence;
 import org.traccar.model.Geofence;
-import org.traccar.model.GeofencePermission;
-import org.traccar.model.GroupGeofence;
 import org.traccar.model.Position;
 
-public class GeofenceManager {
-
-    private final DataManager dataManager;
-
-    private final Map<Long, Geofence> geofences = new HashMap<>();
-    private final Map<Long, Set<Long>> userGeofences = new HashMap<>();
-    private final Map<Long, Set<Long>> groupGeofences = new HashMap<>();
-
-    private final Map<Long, Set<Long>> deviceGeofencesWithGroups = new HashMap<>();
-    private final Map<Long, Set<Long>> deviceGeofences = new HashMap<>();
-
-    private final ReadWriteLock deviceGeofencesLock = new ReentrantReadWriteLock();
-    private final ReadWriteLock geofencesLock = new ReentrantReadWriteLock();
-    private final ReadWriteLock groupGeofencesLock = new ReentrantReadWriteLock();
-    private final ReadWriteLock userGeofencesLock = new ReentrantReadWriteLock();
+public class GeofenceManager extends ExtendedObjectManager {
 
     public GeofenceManager(DataManager dataManager) {
-        this.dataManager = dataManager;
-        refreshGeofences();
-    }
-
-    private Set<Long> getUserGeofences(long userId) {
-        if (!userGeofences.containsKey(userId)) {
-            userGeofences.put(userId, new HashSet<Long>());
-        }
-        return userGeofences.get(userId);
-    }
-
-    public Set<Long> getUserGeofencesIds(long userId) {
-        userGeofencesLock.readLock().lock();
-        try {
-            return getUserGeofences(userId);
-        } finally {
-            userGeofencesLock.readLock().unlock();
-        }
-    }
-
-    private Set<Long> getGroupGeofences(long groupId) {
-        if (!groupGeofences.containsKey(groupId)) {
-            groupGeofences.put(groupId, new HashSet<Long>());
-        }
-        return groupGeofences.get(groupId);
-    }
-
-    public Set<Long> getGroupGeofencesIds(long groupId) {
-        groupGeofencesLock.readLock().lock();
-        try {
-            return getGroupGeofences(groupId);
-        } finally {
-            groupGeofencesLock.readLock().unlock();
-        }
-    }
-
-    public Set<Long> getAllDeviceGeofences(long deviceId) {
-        deviceGeofencesLock.readLock().lock();
-        try {
-            return getDeviceGeofences(deviceGeofencesWithGroups, deviceId);
-        } finally {
-            deviceGeofencesLock.readLock().unlock();
-        }
+        super(dataManager, Geofence.class);
+        refreshItems();
+        refreshExtendedPermissions();
     }
 
-    public Set<Long> getDeviceGeofencesIds(long deviceId) {
-        deviceGeofencesLock.readLock().lock();
-        try {
-            return getDeviceGeofences(deviceGeofences, deviceId);
-        } finally {
-            deviceGeofencesLock.readLock().unlock();
-        }
+    @Override
+    public final void refreshExtendedPermissions() {
+        super.refreshExtendedPermissions();
+        recalculateDevicesGeofences();
     }
 
-    private Set<Long> getDeviceGeofences(Map<Long, Set<Long>> deviceGeofences, long deviceId) {
-        if (!deviceGeofences.containsKey(deviceId)) {
-            deviceGeofences.put(deviceId, new HashSet<Long>());
-        }
-        return deviceGeofences.get(deviceId);
-    }
-
-    public final void refreshGeofences() {
-        if (dataManager != null) {
-            try {
-                geofencesLock.writeLock().lock();
-                try {
-                    geofences.clear();
-                    for (Geofence geofence : dataManager.getGeofences()) {
-                        geofences.put(geofence.getId(), geofence);
-                    }
-                } finally {
-                    geofencesLock.writeLock().unlock();
-                }
-            } catch (SQLException error) {
-                Log.warning(error);
-            }
-        }
-        refreshUserGeofences();
-        refresh();
-    }
-
-    public final void refreshUserGeofences() {
-        if (dataManager != null) {
-            try {
-                userGeofencesLock.writeLock().lock();
-                try {
-                    userGeofences.clear();
-                    for (GeofencePermission geofencePermission : dataManager.getGeofencePermissions()) {
-                        getUserGeofences(geofencePermission.getUserId()).add(geofencePermission.getGeofenceId());
-                    }
-                } finally {
-                    userGeofencesLock.writeLock().unlock();
-                }
-            } catch (SQLException error) {
-                Log.warning(error);
-            }
-        }
-    }
-
-    public final void refresh() {
-        if (dataManager != null) {
-            try {
-
-                Collection<GroupGeofence> databaseGroupGeofences = dataManager.getGroupGeofences();
-                groupGeofencesLock.writeLock().lock();
-                try {
-                    groupGeofences.clear();
-                    for (GroupGeofence groupGeofence : databaseGroupGeofences) {
-                        getGroupGeofences(groupGeofence.getGroupId()).add(groupGeofence.getGeofenceId());
-                    }
-                } finally {
-                    groupGeofencesLock.writeLock().unlock();
-                }
-
-                Collection<DeviceGeofence> databaseDeviceGeofences = dataManager.getDeviceGeofences();
-                Collection<Device> allDevices = Context.getDeviceManager().getAllDevices();
-
-                groupGeofencesLock.readLock().lock();
-                deviceGeofencesLock.writeLock().lock();
-                try {
-                    deviceGeofences.clear();
-                    deviceGeofencesWithGroups.clear();
-
-                    for (DeviceGeofence deviceGeofence : databaseDeviceGeofences) {
-                        getDeviceGeofences(deviceGeofences, deviceGeofence.getDeviceId())
-                            .add(deviceGeofence.getGeofenceId());
-                        getDeviceGeofences(deviceGeofencesWithGroups, deviceGeofence.getDeviceId())
-                            .add(deviceGeofence.getGeofenceId());
-                    }
-
-                    for (Device device : allDevices) {
-                        long groupId = device.getGroupId();
-                        while (groupId != 0) {
-                            getDeviceGeofences(deviceGeofencesWithGroups,
-                                    device.getId()).addAll(getGroupGeofences(groupId));
-                            if (Context.getDeviceManager().getGroupById(groupId) != null) {
-                                groupId = Context.getDeviceManager().getGroupById(groupId).getGroupId();
-                            } else {
-                                groupId = 0;
-                            }
-                        }
-                        List<Long> deviceGeofenceIds = device.getGeofenceIds();
-                        if (deviceGeofenceIds == null) {
-                            deviceGeofenceIds = new ArrayList<>();
-                        } else {
-                            deviceGeofenceIds.clear();
-                        }
-                        Position lastPosition = Context.getIdentityManager().getLastPosition(device.getId());
-                        if (lastPosition != null && deviceGeofencesWithGroups.containsKey(device.getId())) {
-                            for (long geofenceId : deviceGeofencesWithGroups.get(device.getId())) {
-                                Geofence geofence = getGeofence(geofenceId);
-                                if (geofence != null && geofence.getGeometry()
-                                        .containsPoint(lastPosition.getLatitude(), lastPosition.getLongitude())) {
-                                    deviceGeofenceIds.add(geofenceId);
-                                }
-                            }
-                        }
-                        device.setGeofenceIds(deviceGeofenceIds);
-                    }
-
-                } finally {
-                    deviceGeofencesLock.writeLock().unlock();
-                    groupGeofencesLock.readLock().unlock();
-                }
-
-            } catch (SQLException error) {
-                Log.warning(error);
+    public List<Long> getCurrentDeviceGeofences(Position position) {
+        List<Long> result = new ArrayList<>();
+        for (long geofenceId : getAllDeviceItems(position.getDeviceId())) {
+            Geofence geofence = (Geofence) getById(geofenceId);
+            if (geofence != null && geofence.getGeometry()
+                    .containsPoint(position.getLatitude(), position.getLongitude())) {
+                result.add(geofenceId);
             }
         }
+        return result;
     }
 
-    public final Collection<Geofence> getAllGeofences() {
-        geofencesLock.readLock().lock();
-        try {
-            return geofences.values();
-        } finally {
-            geofencesLock.readLock().unlock();
-        }
-    }
-
-    public final Set<Long> getAllGeofencesIds() {
-        geofencesLock.readLock().lock();
-        try {
-            return geofences.keySet();
-        } finally {
-            geofencesLock.readLock().unlock();
-        }
-    }
-
-    public final Set<Long> getManagedGeofencesIds(long userId) {
-        Set<Long> geofences = new HashSet<>();
-        geofences.addAll(getUserGeofencesIds(userId));
-        for (long managedUserId : Context.getPermissionsManager().getUserPermissions(userId)) {
-            geofences.addAll(getUserGeofencesIds(managedUserId));
-        }
-        return geofences;
-    }
-
-    public final Collection<Geofence> getGeofences(Set<Long> geofencesIds) {
-        geofencesLock.readLock().lock();
-        try {
-            Collection<Geofence> result = new LinkedList<>();
-            for (long geofenceId : geofencesIds) {
-                result.add(getGeofence(geofenceId));
+    public void recalculateDevicesGeofences() {
+        for (Device device : Context.getDeviceManager().getAllDevices()) {
+            List<Long> deviceGeofenceIds = device.getGeofenceIds();
+            if (deviceGeofenceIds == null) {
+                deviceGeofenceIds = new ArrayList<>();
+            } else {
+                deviceGeofenceIds.clear();
             }
-            return result;
-        } finally {
-            geofencesLock.readLock().unlock();
-        }
-    }
-
-    public final Geofence getGeofence(long geofenceId) {
-        geofencesLock.readLock().lock();
-        try {
-            return geofences.get(geofenceId);
-        } finally {
-            geofencesLock.readLock().unlock();
-        }
-    }
-
-    public final void updateGeofence(Geofence geofence) {
-        geofencesLock.writeLock().lock();
-        try {
-            geofences.put(geofence.getId(), geofence);
-        } finally {
-            geofencesLock.writeLock().unlock();
-        }
-        try {
-            dataManager.updateGeofence(geofence);
-        } catch (SQLException error) {
-            Log.warning(error);
-        }
-    }
-
-    public boolean checkGeofence(long userId, long geofenceId) {
-        return getUserGeofencesIds(userId).contains(geofenceId);
-    }
-
-    public List<Long> getCurrentDeviceGeofences(Position position) {
-        List<Long> result = new ArrayList<>();
-        for (long geofenceId : getAllDeviceGeofences(position.getDeviceId())) {
-            if (getGeofence(geofenceId).getGeometry().containsPoint(position.getLatitude(), position.getLongitude())) {
-                result.add(geofenceId);
+            Position lastPosition = Context.getIdentityManager().getLastPosition(device.getId());
+            if (lastPosition != null && getAllDeviceItems(device.getId()) != null) {
+                deviceGeofenceIds.addAll(getCurrentDeviceGeofences(lastPosition));
             }
+            device.setGeofenceIds(deviceGeofenceIds);
         }
-        return result;
     }
 
 }
diff --git a/src/org/traccar/database/NotificationManager.java b/src/org/traccar/database/NotificationManager.java
index 48caa615c..0987f255b 100644
--- a/src/org/traccar/database/NotificationManager.java
+++ b/src/org/traccar/database/NotificationManager.java
@@ -49,7 +49,7 @@ public class NotificationManager {
 
     public void updateEvent(Event event, Position position) {
         try {
-            dataManager.addEvent(event);
+            dataManager.addObject(event);
         } catch (SQLException error) {
             Log.warning(error);
         }
@@ -57,7 +57,7 @@ public class NotificationManager {
         Set<Long> users = Context.getPermissionsManager().getDeviceUsers(event.getDeviceId());
         for (long userId : users) {
             if (event.getGeofenceId() == 0 || Context.getGeofenceManager() != null
-                    && Context.getGeofenceManager().checkGeofence(userId, event.getGeofenceId())) {
+                    && Context.getGeofenceManager().checkItemPermission(userId, event.getGeofenceId())) {
                 Notification notification = getUserNotificationByType(userId, event.getType());
                 if (notification != null) {
                     if (notification.getWeb()) {
@@ -105,7 +105,7 @@ public class NotificationManager {
                 notificationsLock.writeLock().lock();
                 try {
                     userNotifications.clear();
-                    for (Notification notification : dataManager.getNotifications()) {
+                    for (Notification notification : dataManager.getObjects(Notification.class)) {
                         getUserNotificationsUnsafe(notification.getUserId()).add(notification);
                     }
                 } finally {
@@ -139,7 +139,7 @@ public class NotificationManager {
                     || cachedNotification.getSms() != notification.getSms()) {
                 if (!notification.getWeb() && !notification.getMail() && !notification.getSms()) {
                     try {
-                        dataManager.removeNotification(cachedNotification);
+                        dataManager.removeObject(Notification.class, cachedNotification.getId());
                     } catch (SQLException error) {
                         Log.warning(error);
                     }
@@ -160,7 +160,7 @@ public class NotificationManager {
                         notificationsLock.writeLock().unlock();
                     }
                     try {
-                        dataManager.updateNotification(cachedNotification);
+                        dataManager.updateObject(cachedNotification);
                     } catch (SQLException error) {
                         Log.warning(error);
                     }
@@ -170,7 +170,7 @@ public class NotificationManager {
             }
         } else if (notification.getWeb() || notification.getMail() || notification.getSms()) {
             try {
-                dataManager.addNotification(notification);
+                dataManager.addObject(notification);
             } catch (SQLException error) {
                 Log.warning(error);
             }
diff --git a/src/org/traccar/database/PermissionsManager.java b/src/org/traccar/database/PermissionsManager.java
index 82ca6af49..b9cdfc36b 100644
--- a/src/org/traccar/database/PermissionsManager.java
+++ b/src/org/traccar/database/PermissionsManager.java
@@ -17,13 +17,16 @@ package org.traccar.database;
 
 import org.traccar.Context;
 import org.traccar.helper.Log;
+import org.traccar.model.Attribute;
+import org.traccar.model.Calendar;
 import org.traccar.model.Device;
-import org.traccar.model.DevicePermission;
+import org.traccar.model.Driver;
+import org.traccar.model.Geofence;
 import org.traccar.model.Group;
-import org.traccar.model.GroupPermission;
+import org.traccar.model.ManagedUser;
+import org.traccar.model.Permission;
 import org.traccar.model.Server;
 import org.traccar.model.User;
-import org.traccar.model.UserPermission;
 
 import java.lang.reflect.Method;
 import java.sql.SQLException;
@@ -98,7 +101,7 @@ public class PermissionsManager {
         usersTokens.clear();
         try {
             server = dataManager.getServer();
-            for (User user : dataManager.getUsers()) {
+            for (User user : dataManager.getObjects(User.class)) {
                 users.put(user.getId(), user);
                 if (user.getToken() != null) {
                     usersTokens.put(user.getToken(), user.getId());
@@ -112,8 +115,9 @@ public class PermissionsManager {
     public final void refreshUserPermissions() {
         userPermissions.clear();
         try {
-            for (UserPermission permission : dataManager.getUserPermissions()) {
-                getUserPermissions(permission.getUserId()).add(permission.getManagedUserId());
+            for (Map<String, Long> permission : dataManager.getPermissions(User.class, User.class)) {
+                getUserPermissions(permission.get(DataManager.makeNameId(User.class)))
+                        .add(permission.get(DataManager.makeNameId(ManagedUser.class)));
             }
         } catch (SQLException error) {
             Log.warning(error);
@@ -126,19 +130,23 @@ public class PermissionsManager {
         try {
             GroupTree groupTree = new GroupTree(Context.getDeviceManager().getAllGroups(),
                     Context.getDeviceManager().getAllDevices());
-            for (GroupPermission permission : dataManager.getGroupPermissions()) {
-                Set<Long> userGroupPermissions = getGroupPermissions(permission.getUserId());
-                Set<Long> userDevicePermissions = getDevicePermissions(permission.getUserId());
-                userGroupPermissions.add(permission.getGroupId());
-                for (Group group : groupTree.getGroups(permission.getGroupId())) {
+            for (Map<String, Long> groupPermission : dataManager.getPermissions(User.class, Group.class)) {
+                Set<Long> userGroupPermissions = getGroupPermissions(groupPermission
+                        .get(DataManager.makeNameId(User.class)));
+                Set<Long> userDevicePermissions = getDevicePermissions(groupPermission
+                        .get(DataManager.makeNameId(User.class)));
+                userGroupPermissions.add(groupPermission.get(DataManager.makeNameId(Group.class)));
+                for (Group group : groupTree.getGroups(groupPermission.get(DataManager.makeNameId(Group.class)))) {
                     userGroupPermissions.add(group.getId());
                 }
-                for (Device device : groupTree.getDevices(permission.getGroupId())) {
+                for (Device device : groupTree.getDevices(groupPermission.get(DataManager.makeNameId(Group.class)))) {
                     userDevicePermissions.add(device.getId());
                 }
             }
-            for (DevicePermission permission : dataManager.getDevicePermissions()) {
-                getDevicePermissions(permission.getUserId()).add(permission.getDeviceId());
+
+            for (Map<String, Long> devicePermission : dataManager.getPermissions(User.class, Device.class)) {
+                getDevicePermissions(devicePermission.get(DataManager.makeNameId(User.class)))
+                        .add(devicePermission.get(DataManager.makeNameId(Device.class)));
             }
 
             groupDevices.clear();
@@ -298,52 +306,72 @@ public class PermissionsManager {
         }
     }
 
-    public void checkGeofence(long userId, long geofenceId) throws SecurityException {
-        if (!Context.getGeofenceManager().checkGeofence(userId, geofenceId) && !isAdmin(userId)) {
-            checkManager(userId);
-            for (long managedUserId : getUserPermissions(userId)) {
-                if (Context.getGeofenceManager().checkGeofence(managedUserId, geofenceId)) {
-                    return;
-                }
-            }
-            throw new SecurityException("Geofence access denied");
+    public void checkPermission(Class<?> object, long userId, long objectId)
+            throws SecurityException {
+        SimpleObjectManager manager = null;
+
+        if (object.equals(Device.class)) {
+            checkDevice(userId, objectId);
+        } else if (object.equals(Group.class)) {
+            checkGroup(userId, objectId);
+        } else if (object.equals(User.class) || object.equals(ManagedUser.class)) {
+            checkUser(userId, objectId);
+        } else if (object.equals(Geofence.class)) {
+            manager = Context.getGeofenceManager();
+        } else if (object.equals(Attribute.class)) {
+            manager = Context.getAttributesManager();
+        } else if (object.equals(Driver.class)) {
+            manager = Context.getDriversManager();
+        } else if (object.equals(Calendar.class)) {
+            manager = Context.getCalendarManager();
+        } else {
+            throw new IllegalArgumentException("Unknown object type");
         }
-    }
 
-    public void checkAttribute(long userId, long attributeId) throws SecurityException {
-        if (!Context.getAttributesManager().checkAttribute(userId, attributeId) && !isAdmin(userId)) {
+        if (manager != null && !manager.checkItemPermission(userId, objectId) && !isAdmin(userId)) {
             checkManager(userId);
             for (long managedUserId : getUserPermissions(userId)) {
-                if (Context.getAttributesManager().checkAttribute(managedUserId, attributeId)) {
+                if (manager.checkItemPermission(managedUserId, objectId)) {
                     return;
                 }
             }
-            throw new SecurityException("Attribute access denied");
-        }
-    }
-
-    public void checkDriver(long userId, long driverId) throws SecurityException {
-        if (!Context.getDriversManager().checkDriver(userId, driverId) && !isAdmin(userId)) {
-            checkManager(userId);
-            for (long managedUserId : getUserPermissions(userId)) {
-                if (Context.getDriversManager().checkDriver(managedUserId, driverId)) {
-                    return;
-                }
+            throw new SecurityException("Type " + object + " access denied");
+        }
+    }
+
+    public void refreshAllExtendedPermissions() {
+        if (Context.getGeofenceManager() != null) {
+            Context.getGeofenceManager().refreshExtendedPermissions();
+        }
+        Context.getDriversManager().refreshExtendedPermissions();
+        Context.getAttributesManager().refreshExtendedPermissions();
+    }
+
+    public void refreshPermissions(Permission permission) {
+        if (permission.getOwnerClass().equals(User.class)) {
+            if (permission.getPropertyClass().equals(Device.class)
+                    || permission.getPropertyClass().equals(Group.class)) {
+                refreshPermissions();
+                refreshAllExtendedPermissions();
+            } else if (permission.getPropertyClass().equals(ManagedUser.class)) {
+                refreshUserPermissions();
+            } else if (permission.getPropertyClass().equals(Geofence.class) && Context.getGeofenceManager() != null) {
+                Context.getGeofenceManager().refreshUserItems();
+            } else if (permission.getPropertyClass().equals(Driver.class)) {
+                Context.getDriversManager().refreshUserItems();
+            } else if (permission.getPropertyClass().equals(Attribute.class)) {
+                Context.getAttributesManager().refreshUserItems();
+            } else if (permission.getPropertyClass().equals(Calendar.class)) {
+                Context.getCalendarManager().refreshUserItems();
             }
-            throw new SecurityException("Driver access denied");
-        }
-    }
-
-
-    public void checkCalendar(long userId, long calendarId) throws SecurityException {
-        if (!Context.getCalendarManager().checkCalendar(userId, calendarId) && !isAdmin(userId)) {
-            checkManager(userId);
-            for (long managedUserId : getUserPermissions(userId)) {
-                if (Context.getCalendarManager().checkCalendar(managedUserId, calendarId)) {
-                    return;
-                }
+        } else if (permission.getOwnerClass().equals(Device.class) || permission.getOwnerClass().equals(Group.class)) {
+            if (permission.getPropertyClass().equals(Geofence.class) && Context.getGeofenceManager() != null) {
+                Context.getGeofenceManager().refreshExtendedPermissions();
+            } else if (permission.getPropertyClass().equals(Driver.class)) {
+                Context.getDriversManager().refreshExtendedPermissions();
+            } else if (permission.getPropertyClass().equals(Attribute.class)) {
+                Context.getAttributesManager().refreshExtendedPermissions();
             }
-            throw new SecurityException("Calendar access denied");
         }
     }
 
@@ -352,7 +380,7 @@ public class PermissionsManager {
     }
 
     public void updateServer(Server server) throws SQLException {
-        dataManager.updateServer(server);
+        dataManager.updateObject(server);
         this.server = server;
     }
 
@@ -379,7 +407,7 @@ public class PermissionsManager {
     }
 
     public void addUser(User user) throws SQLException {
-        dataManager.addUser(user);
+        dataManager.addObject(user);
         users.put(user.getId(), user);
         if (user.getToken() != null) {
             usersTokens.put(user.getToken(), user.getId());
@@ -401,7 +429,7 @@ public class PermissionsManager {
     }
 
     public void removeUser(long userId) throws SQLException {
-        dataManager.removeUser(userId);
+        dataManager.removeObject(User.class, userId);
         usersTokens.remove(users.get(userId).getToken());
         users.remove(userId);
         refreshPermissions();
diff --git a/src/org/traccar/database/QueryBuilder.java b/src/org/traccar/database/QueryBuilder.java
index a24e6f0bf..440690a76 100644
--- a/src/org/traccar/database/QueryBuilder.java
+++ b/src/org/traccar/database/QueryBuilder.java
@@ -35,6 +35,7 @@ import java.sql.Types;
 import java.util.Collection;
 import java.util.Date;
 import java.util.HashMap;
+import java.util.LinkedHashMap;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
@@ -487,4 +488,28 @@ public final class QueryBuilder {
         return 0;
     }
 
+    public <T> Collection<Map<String, T>> executeMapQuery(Class<T> clazz) throws SQLException {
+        List<Map<String, T>> result = new LinkedList<>();
+        if (query != null) {
+            try {
+                try (ResultSet resultSet = statement.executeQuery()) {
+                    ResultSetMetaData resultMetaData = resultSet.getMetaData();
+                    while (resultSet.next()) {
+                        LinkedHashMap<String, T> map = new LinkedHashMap<>();
+                        for (int i = 1; i <= resultMetaData.getColumnCount(); i++) {
+                            String label = resultMetaData.getColumnLabel(i);
+                            map.put(label, resultSet.getObject(label, clazz));
+                        }
+                        result.add(map);
+                    }
+                }
+            } finally {
+                statement.close();
+                connection.close();
+            }
+        }
+
+        return result;
+    }
+
 }
diff --git a/src/org/traccar/database/SimpleObjectManager.java b/src/org/traccar/database/SimpleObjectManager.java
new file mode 100644
index 000000000..0db8af658
--- /dev/null
+++ b/src/org/traccar/database/SimpleObjectManager.java
@@ -0,0 +1,159 @@
+/*
+ * Copyright 2017 Anton Tananaev (anton@traccar.org)
+ * Copyright 2017 Andrey Kunitsyn (andrey@traccar.org)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.traccar.database;
+
+import java.sql.SQLException;
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.LinkedList;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+
+import org.traccar.Context;
+import org.traccar.helper.Log;
+import org.traccar.model.BaseModel;
+import org.traccar.model.User;
+
+public abstract class SimpleObjectManager {
+
+    private final DataManager dataManager;
+
+    private final Map<Long, BaseModel> items = new ConcurrentHashMap<>();
+    private final Map<Long, Set<Long>> userItems = new ConcurrentHashMap<>();
+
+    private Class<? extends BaseModel> baseClass;
+    private String baseClassIdName;
+
+    protected SimpleObjectManager(DataManager dataManager, Class<? extends BaseModel> baseClass) {
+        this.dataManager = dataManager;
+        this.baseClass = baseClass;
+        baseClassIdName = DataManager.makeNameId(baseClass);
+    }
+
+    protected final DataManager getDataManager() {
+        return dataManager;
+    }
+
+    protected final Class<? extends BaseModel> getBaseClass() {
+        return baseClass;
+    }
+
+    protected final String getBaseClassIdName() {
+        return baseClassIdName;
+    }
+
+    public final BaseModel getById(long itemId) {
+        return items.get(itemId);
+    }
+
+    protected final void clearItems() {
+        items.clear();
+    }
+
+    protected final void putItem(long itemId, BaseModel item) {
+        items.put(itemId, item);
+    }
+
+    protected final void removeCachedItem(long itemId) {
+        items.remove(itemId);
+    }
+
+    public final Set<Long> getUserItems(long userId) {
+        if (!userItems.containsKey(userId)) {
+            userItems.put(userId, new HashSet<Long>());
+        }
+        return userItems.get(userId);
+    }
+
+    protected final void clearUserItems() {
+        userItems.clear();
+    }
+
+    public final boolean checkItemPermission(long userId, long itemId) {
+        return getUserItems(userId).contains(itemId);
+    }
+
+    public void refreshItems() {
+        if (dataManager != null) {
+            try {
+                clearItems();
+                for (BaseModel item : dataManager.getObjects(this.baseClass)) {
+                    putItem(item.getId(), item);
+                }
+            } catch (SQLException error) {
+                Log.warning(error);
+            }
+        }
+        refreshUserItems();
+    }
+
+    public final void refreshUserItems() {
+        if (dataManager != null) {
+            try {
+                clearUserItems();
+                for (Map<String, Long> permission : dataManager.getPermissions(User.class, baseClass)) {
+                    getUserItems(permission.get(DataManager.makeNameId(User.class)))
+                            .add(permission.get(baseClassIdName));
+                }
+            } catch (SQLException error) {
+                Log.warning(error);
+            }
+        }
+    }
+
+    public void addItem(BaseModel item) throws SQLException {
+        dataManager.addObject(item);
+        putItem(item.getId(), item);
+    }
+
+    public void updateItem(BaseModel item) throws SQLException {
+        dataManager.updateObject(item);
+        putItem(item.getId(), item);
+    }
+
+    public void removeItem(long itemId) throws SQLException {
+        BaseModel item = getById(itemId);
+        if (item != null) {
+            dataManager.removeObject(baseClass, itemId);
+            removeCachedItem(itemId);
+        }
+        refreshUserItems();
+    }
+
+    public final <T> Collection<T> getItems(Class<T> clazz, Set<Long> itemIds) {
+        Collection<T> result = new LinkedList<>();
+        for (long itemId : itemIds) {
+            result.add((T) getById(itemId));
+        }
+        return result;
+    }
+
+    public final Set<Long> getAllItems() {
+        return items.keySet();
+    }
+
+    public final Set<Long> getManagedItems(long userId) {
+        Set<Long> result = new HashSet<>();
+        result.addAll(getUserItems(userId));
+        for (long managedUserId : Context.getPermissionsManager().getUserPermissions(userId)) {
+            result.addAll(getUserItems(managedUserId));
+        }
+        return result;
+    }
+
+}
diff --git a/src/org/traccar/events/GeofenceEventHandler.java b/src/org/traccar/events/GeofenceEventHandler.java
index fbec932b1..516df9d69 100644
--- a/src/org/traccar/events/GeofenceEventHandler.java
+++ b/src/org/traccar/events/GeofenceEventHandler.java
@@ -22,8 +22,10 @@ import java.util.List;
 import org.traccar.BaseEventHandler;
 import org.traccar.Context;
 import org.traccar.database.GeofenceManager;
+import org.traccar.model.Calendar;
 import org.traccar.model.Device;
 import org.traccar.model.Event;
+import org.traccar.model.Geofence;
 import org.traccar.model.Position;
 
 public class GeofenceEventHandler extends BaseEventHandler {
@@ -57,18 +59,18 @@ public class GeofenceEventHandler extends BaseEventHandler {
 
         Collection<Event> events = new ArrayList<>();
         for (long geofenceId : newGeofences) {
-            long calendarId = geofenceManager.getGeofence(geofenceId).getCalendarId();
-            if (calendarId == 0 || Context.getCalendarManager().getCalendar(calendarId) == null
-                    || Context.getCalendarManager().getCalendar(calendarId).checkMoment(position.getFixTime())) {
+            long calendarId = ((Geofence) geofenceManager.getById(geofenceId)).getCalendarId();
+            Calendar calendar = calendarId != 0 ? (Calendar) Context.getCalendarManager().getById(calendarId) : null;
+            if (calendar == null || calendar.checkMoment(position.getFixTime())) {
                 Event event = new Event(Event.TYPE_GEOFENCE_ENTER, position.getDeviceId(), position.getId());
                 event.setGeofenceId(geofenceId);
                 events.add(event);
             }
         }
         for (long geofenceId : oldGeofences) {
-            long calendarId = geofenceManager.getGeofence(geofenceId).getCalendarId();
-            if (calendarId == 0 || Context.getCalendarManager().getCalendar(calendarId) == null
-                    || Context.getCalendarManager().getCalendar(calendarId).checkMoment(position.getFixTime())) {
+            long calendarId = ((Geofence) geofenceManager.getById(geofenceId)).getCalendarId();
+            Calendar calendar = calendarId != 0 ? (Calendar) Context.getCalendarManager().getById(calendarId) : null;
+            if (calendar == null || calendar.checkMoment(position.getFixTime())) {
                 Event event = new Event(Event.TYPE_GEOFENCE_EXIT, position.getDeviceId(), position.getId());
                 event.setGeofenceId(geofenceId);
                 events.add(event);
diff --git a/src/org/traccar/model/Attribute.java b/src/org/traccar/model/Attribute.java
index 9c3b5e43b..45d40b3ec 100644
--- a/src/org/traccar/model/Attribute.java
+++ b/src/org/traccar/model/Attribute.java
@@ -16,17 +16,7 @@
  */
 package org.traccar.model;
 
-public class Attribute {
-
-    private long id;
-
-    public long getId() {
-        return id;
-    }
-
-    public void setId(long id) {
-        this.id = id;
-    }
+public class Attribute extends BaseModel {
 
     private String description;
 
diff --git a/src/org/traccar/model/AttributeAlias.java b/src/org/traccar/model/AttributeAlias.java
index 2835c0558..1599ab939 100644
--- a/src/org/traccar/model/AttributeAlias.java
+++ b/src/org/traccar/model/AttributeAlias.java
@@ -16,17 +16,7 @@
  */
 package org.traccar.model;
 
-public class AttributeAlias {
-
-    private long id;
-
-    public long getId() {
-        return id;
-    }
-
-    public void setId(long id) {
-        this.id = id;
-    }
+public class AttributeAlias extends BaseModel {
 
     private long deviceId;
 
diff --git a/src/org/traccar/model/AttributePermission.java b/src/org/traccar/model/AttributePermission.java
deleted file mode 100644
index fe2fe7b6e..000000000
--- a/src/org/traccar/model/AttributePermission.java
+++ /dev/null
@@ -1,41 +0,0 @@
-/*
- * Copyright 2017 Anton Tananaev (anton@traccar.org)
- * Copyright 2017 Andrey Kunitsyn (andrey@traccar.org)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.traccar.model;
-
-public class AttributePermission {
-
-    private long userId;
-
-    public long getUserId() {
-        return userId;
-    }
-
-    public void setUserId(long userId) {
-        this.userId = userId;
-    }
-
-    private long attributeId;
-
-    public long getAttributeId() {
-        return attributeId;
-    }
-
-    public void setAttributeId(long attributeId) {
-        this.attributeId = attributeId;
-    }
-
-}
diff --git a/src/org/traccar/model/DriverPermission.java b/src/org/traccar/model/BaseModel.java
index cdbcc4a50..8bdb916e8 100644
--- a/src/org/traccar/model/DriverPermission.java
+++ b/src/org/traccar/model/BaseModel.java
@@ -16,25 +16,16 @@
  */
 package org.traccar.model;
 
-public class DriverPermission {
+public class BaseModel {
 
-    private long userId;
+    private long id;
 
-    public long getUserId() {
-        return userId;
+    public final long getId() {
+        return id;
     }
 
-    public void setUserId(long userId) {
-        this.userId = userId;
+    public final void setId(long id) {
+        this.id = id;
     }
 
-    private long driverId;
-
-    public long getDriverId() {
-        return driverId;
-    }
-
-    public void setDriverId(long driverId) {
-        this.driverId = driverId;
-    }
 }
diff --git a/src/org/traccar/model/Calendar.java b/src/org/traccar/model/Calendar.java
index 55f696d50..3d855b1be 100644
--- a/src/org/traccar/model/Calendar.java
+++ b/src/org/traccar/model/Calendar.java
@@ -34,7 +34,7 @@ import net.fortuna.ical4j.model.Period;
 import net.fortuna.ical4j.model.component.CalendarComponent;
 import org.traccar.database.QueryIgnore;
 
-public class Calendar extends Extensible {
+public class Calendar extends ExtendedModel {
 
     private String name;
 
diff --git a/src/org/traccar/model/CalendarPermission.java b/src/org/traccar/model/CalendarPermission.java
deleted file mode 100644
index 59f54e07b..000000000
--- a/src/org/traccar/model/CalendarPermission.java
+++ /dev/null
@@ -1,40 +0,0 @@
-/*
- * Copyright 2016 Anton Tananaev (anton@traccar.org)
- * Copyright 2016 Andrey Kunitsyn (andrey@traccar.org)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.traccar.model;
-
-public class CalendarPermission {
-
-    private long userId;
-
-    public long getUserId() {
-        return userId;
-    }
-
-    public void setUserId(long userId) {
-        this.userId = userId;
-    }
-
-    private long calendarId;
-
-    public long getCalendarId() {
-        return calendarId;
-    }
-
-    public void setCalendarId(long calendarId) {
-        this.calendarId = calendarId;
-    }
-}
diff --git a/src/org/traccar/model/Device.java b/src/org/traccar/model/Device.java
index 2324da532..6a13c2b77 100644
--- a/src/org/traccar/model/Device.java
+++ b/src/org/traccar/model/Device.java
@@ -18,7 +18,7 @@ package org.traccar.model;
 import java.util.Date;
 import java.util.List;
 
-public class Device extends Extensible {
+public class Device extends ExtendedModel {
 
     private String name;
 
diff --git a/src/org/traccar/model/DeviceAttribute.java b/src/org/traccar/model/DeviceAttribute.java
deleted file mode 100644
index e0ac6dd98..000000000
--- a/src/org/traccar/model/DeviceAttribute.java
+++ /dev/null
@@ -1,40 +0,0 @@
-/*
- * Copyright 2017 Anton Tananaev (anton@traccar.org)
- * Copyright 2017 Andrey Kunitsyn (andrey@traccar.org)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.traccar.model;
-
-public class DeviceAttribute {
-
-    private long deviceId;
-
-    public long getDeviceId() {
-        return deviceId;
-    }
-
-    public void setDeviceId(long deviceId) {
-        this.deviceId = deviceId;
-    }
-
-    private long attributeId;
-
-    public long getAttributeId() {
-        return attributeId;
-    }
-
-    public void setAttributeId(long attributeId) {
-        this.attributeId = attributeId;
-    }
-}
diff --git a/src/org/traccar/model/DeviceDriver.java b/src/org/traccar/model/DeviceDriver.java
deleted file mode 100644
index 2008aaddf..000000000
--- a/src/org/traccar/model/DeviceDriver.java
+++ /dev/null
@@ -1,41 +0,0 @@
-/*
- * Copyright 2017 Anton Tananaev (anton@traccar.org)
- * Copyright 2017 Andrey Kunitsyn (andrey@traccar.org)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.traccar.model;
-
-public class DeviceDriver {
-
-    private long deviceId;
-
-    public long getDeviceId() {
-        return deviceId;
-    }
-
-    public void setDeviceId(long deviceId) {
-        this.deviceId = deviceId;
-    }
-
-    private long driverId;
-
-    public long getDriverId() {
-        return driverId;
-    }
-
-    public void setDriverId(long driverId) {
-        this.driverId = driverId;
-    }
-
-}
diff --git a/src/org/traccar/model/DeviceGeofence.java b/src/org/traccar/model/DeviceGeofence.java
deleted file mode 100644
index 00c99add6..000000000
--- a/src/org/traccar/model/DeviceGeofence.java
+++ /dev/null
@@ -1,40 +0,0 @@
-/*
- * Copyright 2016 Anton Tananaev (anton@traccar.org)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.traccar.model;
-
-public class DeviceGeofence {
-
-    private long deviceId;
-
-    public long getDeviceId() {
-        return deviceId;
-    }
-
-    public void setDeviceId(long deviceId) {
-        this.deviceId = deviceId;
-    }
-
-    private long geofenceId;
-
-    public long getGeofenceId() {
-        return geofenceId;
-    }
-
-    public void setGeofenceId(long geofenceId) {
-        this.geofenceId = geofenceId;
-    }
-
-}
diff --git a/src/org/traccar/model/DevicePermission.java b/src/org/traccar/model/DevicePermission.java
deleted file mode 100644
index c62173132..000000000
--- a/src/org/traccar/model/DevicePermission.java
+++ /dev/null
@@ -1,40 +0,0 @@
-/*
- * Copyright 2015 - 2016 Anton Tananaev (anton@traccar.org)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.traccar.model;
-
-public class DevicePermission {
-
-    private long userId;
-
-    public long getUserId() {
-        return userId;
-    }
-
-    public void setUserId(long userId) {
-        this.userId = userId;
-    }
-
-    private long deviceId;
-
-    public long getDeviceId() {
-        return deviceId;
-    }
-
-    public void setDeviceId(long deviceId) {
-        this.deviceId = deviceId;
-    }
-
-}
diff --git a/src/org/traccar/model/Driver.java b/src/org/traccar/model/Driver.java
index 7a51d9151..05f52fd4d 100644
--- a/src/org/traccar/model/Driver.java
+++ b/src/org/traccar/model/Driver.java
@@ -16,7 +16,7 @@
  */
 package org.traccar.model;
 
-public class Driver extends Extensible {
+public class Driver extends ExtendedModel {
 
     private String name;
 
diff --git a/src/org/traccar/model/Extensible.java b/src/org/traccar/model/ExtendedModel.java
index b7953d8a6..a4bf00e70 100644
--- a/src/org/traccar/model/Extensible.java
+++ b/src/org/traccar/model/ExtendedModel.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 Anton Tananaev (anton@traccar.org)
+ * Copyright 2016 - 2017 Anton Tananaev (anton@traccar.org)
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,17 +18,7 @@ package org.traccar.model;
 import java.util.LinkedHashMap;
 import java.util.Map;
 
-public class Extensible {
-
-    private long id;
-
-    public long getId() {
-        return id;
-    }
-
-    public void setId(long id) {
-        this.id = id;
-    }
+public class ExtendedModel extends BaseModel {
 
     private Map<String, Object> attributes = new LinkedHashMap<>();
 
diff --git a/src/org/traccar/model/Geofence.java b/src/org/traccar/model/Geofence.java
index dfb888852..21c196da9 100644
--- a/src/org/traccar/model/Geofence.java
+++ b/src/org/traccar/model/Geofence.java
@@ -26,7 +26,7 @@ import org.traccar.geofence.GeofencePolyline;
 
 import com.fasterxml.jackson.annotation.JsonIgnore;
 
-public class Geofence extends Extensible {
+public class Geofence extends ExtendedModel {
 
     public static final String TYPE_GEOFENCE_CILCLE = "geofenceCircle";
     public static final String TYPE_GEOFENCE_POLYGON = "geofencePolygon";
diff --git a/src/org/traccar/model/GeofencePermission.java b/src/org/traccar/model/GeofencePermission.java
deleted file mode 100644
index 464f4e9eb..000000000
--- a/src/org/traccar/model/GeofencePermission.java
+++ /dev/null
@@ -1,40 +0,0 @@
-/*
- * Copyright 2016 Anton Tananaev (anton@traccar.org)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.traccar.model;
-
-public class GeofencePermission {
-
-    private long userId;
-
-    public long getUserId() {
-        return userId;
-    }
-
-    public void setUserId(long userId) {
-        this.userId = userId;
-    }
-
-    private long geofenceId;
-
-    public long getGeofenceId() {
-        return geofenceId;
-    }
-
-    public void setGeofenceId(long geofenceId) {
-        this.geofenceId = geofenceId;
-    }
-
-}
diff --git a/src/org/traccar/model/Group.java b/src/org/traccar/model/Group.java
index c21d43127..aad206aad 100644
--- a/src/org/traccar/model/Group.java
+++ b/src/org/traccar/model/Group.java
@@ -15,7 +15,7 @@
  */
 package org.traccar.model;
 
-public class Group extends Extensible {
+public class Group extends ExtendedModel {
 
     private String name;
 
diff --git a/src/org/traccar/model/GroupAttribute.java b/src/org/traccar/model/GroupAttribute.java
deleted file mode 100644
index a7e8a80bc..000000000
--- a/src/org/traccar/model/GroupAttribute.java
+++ /dev/null
@@ -1,40 +0,0 @@
-/*
- * Copyright 2017 Anton Tananaev (anton@traccar.org)
- * Copyright 2017 Andrey Kunitsyn (andrey@traccar.org)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.traccar.model;
-
-public class GroupAttribute {
-
-    private long groupId;
-
-    public long getGroupId() {
-        return groupId;
-    }
-
-    public void setGroupId(long groupId) {
-        this.groupId = groupId;
-    }
-
-    private long attributeId;
-
-    public long getAttributeId() {
-        return attributeId;
-    }
-
-    public void setAttributeId(long attributeId) {
-        this.attributeId = attributeId;
-    }
-}
diff --git a/src/org/traccar/model/GroupGeofence.java b/src/org/traccar/model/GroupGeofence.java
deleted file mode 100644
index 736e6c704..000000000
--- a/src/org/traccar/model/GroupGeofence.java
+++ /dev/null
@@ -1,40 +0,0 @@
-/*
- * Copyright 2016 Anton Tananaev (anton@traccar.org)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.traccar.model;
-
-public class GroupGeofence {
-
-    private long groupId;
-
-    public long getGroupId() {
-        return groupId;
-    }
-
-    public void setGroupId(long groupId) {
-        this.groupId = groupId;
-    }
-
-    private long geofenceId;
-
-    public long getGeofenceId() {
-        return geofenceId;
-    }
-
-    public void setGeofenceId(long geofenceId) {
-        this.geofenceId = geofenceId;
-    }
-
-}
diff --git a/src/org/traccar/model/GroupPermission.java b/src/org/traccar/model/GroupPermission.java
deleted file mode 100644
index 59b41b049..000000000
--- a/src/org/traccar/model/GroupPermission.java
+++ /dev/null
@@ -1,40 +0,0 @@
-/*
- * Copyright 2016 Anton Tananaev (anton@traccar.org)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.traccar.model;
-
-public class GroupPermission {
-
-    private long userId;
-
-    public long getUserId() {
-        return userId;
-    }
-
-    public void setUserId(long userId) {
-        this.userId = userId;
-    }
-
-    private long groupId;
-
-    public long getGroupId() {
-        return groupId;
-    }
-
-    public void setGroupId(long groupId) {
-        this.groupId = groupId;
-    }
-
-}
diff --git a/src/org/traccar/model/GroupDriver.java b/src/org/traccar/model/ManagedUser.java
index 91b205923..03c5ef48d 100644
--- a/src/org/traccar/model/GroupDriver.java
+++ b/src/org/traccar/model/ManagedUser.java
@@ -16,26 +16,6 @@
  */
 package org.traccar.model;
 
-public class GroupDriver {
-
-    private long groupId;
-
-    public long getGroupId() {
-        return groupId;
-    }
-
-    public void setGroupId(long groupId) {
-        this.groupId = groupId;
-    }
-
-    private long driverId;
-
-    public long getDriverId() {
-        return driverId;
-    }
-
-    public void setDriverId(long driverId) {
-        this.driverId = driverId;
-    }
+public class ManagedUser extends User {
 
 }
diff --git a/src/org/traccar/model/Message.java b/src/org/traccar/model/Message.java
index ab472202b..dad9c20f0 100644
--- a/src/org/traccar/model/Message.java
+++ b/src/org/traccar/model/Message.java
@@ -15,7 +15,7 @@
  */
 package org.traccar.model;
 
-public class Message extends Extensible {
+public class Message extends ExtendedModel {
 
     private long deviceId;
 
diff --git a/src/org/traccar/model/Notification.java b/src/org/traccar/model/Notification.java
index 6c61cafaf..e7bb69903 100644
--- a/src/org/traccar/model/Notification.java
+++ b/src/org/traccar/model/Notification.java
@@ -15,7 +15,7 @@
  */
 package org.traccar.model;
 
-public class Notification extends Extensible {
+public class Notification extends ExtendedModel {
 
     private long userId;
 
diff --git a/src/org/traccar/model/Permission.java b/src/org/traccar/model/Permission.java
new file mode 100644
index 000000000..1006b1c47
--- /dev/null
+++ b/src/org/traccar/model/Permission.java
@@ -0,0 +1,57 @@
+/*
+ * Copyright 2017 Anton Tananaev (anton@traccar.org)
+ * Copyright 2017 Andrey Kunitsyn (andrey@traccar.org)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.traccar.model;
+
+import java.util.Iterator;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+import org.traccar.database.DataManager;
+
+public class Permission {
+
+    private Class<?> ownerClass;
+    private long ownerId;
+    private Class<?> propertyClass;
+    private long propertyId;
+
+    public Permission(LinkedHashMap<String, Long> permissionMap) throws ClassNotFoundException {
+        Iterator<Map.Entry<String, Long>> iterator = permissionMap.entrySet().iterator();
+        String owner = iterator.next().getKey();
+        ownerClass = DataManager.getClassByName(owner);
+        String property = iterator.next().getKey();
+        propertyClass = DataManager.getClassByName(property);
+        ownerId = permissionMap.get(owner);
+        propertyId = permissionMap.get(property);
+    }
+
+    public Class<?> getOwnerClass() {
+        return ownerClass;
+    }
+
+    public long getOwnerId() {
+        return ownerId;
+    }
+
+    public Class<?> getPropertyClass() {
+        return propertyClass;
+    }
+
+    public long getPropertyId() {
+        return propertyId;
+    }
+}
diff --git a/src/org/traccar/model/Server.java b/src/org/traccar/model/Server.java
index 4ded65204..cd5b0624e 100644
--- a/src/org/traccar/model/Server.java
+++ b/src/org/traccar/model/Server.java
@@ -19,7 +19,7 @@ import java.util.TimeZone;
 
 import org.traccar.helper.Log;
 
-public class Server extends Extensible {
+public class Server extends ExtendedModel {
 
     public String getVersion() {
         return Log.getAppVersion();
diff --git a/src/org/traccar/model/Statistics.java b/src/org/traccar/model/Statistics.java
index c7ae5af7a..2acf8514f 100644
--- a/src/org/traccar/model/Statistics.java
+++ b/src/org/traccar/model/Statistics.java
@@ -17,7 +17,7 @@ package org.traccar.model;
 
 import java.util.Date;
 
-public class Statistics extends Extensible {
+public class Statistics extends ExtendedModel {
 
     private Date captureTime;
 
diff --git a/src/org/traccar/model/User.java b/src/org/traccar/model/User.java
index 366ced503..6e6a079c2 100644
--- a/src/org/traccar/model/User.java
+++ b/src/org/traccar/model/User.java
@@ -21,7 +21,7 @@ import org.traccar.helper.Hashing;
 import java.util.Date;
 import java.util.TimeZone;
 
-public class User extends Extensible {
+public class User extends ExtendedModel {
 
     private String name;
 
diff --git a/src/org/traccar/model/UserPermission.java b/src/org/traccar/model/UserPermission.java
deleted file mode 100644
index 39ead5ef1..000000000
--- a/src/org/traccar/model/UserPermission.java
+++ /dev/null
@@ -1,41 +0,0 @@
-/*
- * Copyright 2017 Anton Tananaev (anton@traccar.org)
- * Copyright 2017 Andrey Kunitsyn (andrey@traccar.org)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.traccar.model;
-
-public class UserPermission {
-
-    private long userId;
-
-    public long getUserId() {
-        return userId;
-    }
-
-    public void setUserId(long userId) {
-        this.userId = userId;
-    }
-
-    private long managedUserId;
-
-    public long getManagedUserId() {
-        return managedUserId;
-    }
-
-    public void setManagedUserId(long managedUserId) {
-        this.managedUserId = managedUserId;
-    }
-
-}
diff --git a/src/org/traccar/notification/EventForwarder.java b/src/org/traccar/notification/EventForwarder.java
index bd7cfc0c5..08f55df75 100644
--- a/src/org/traccar/notification/EventForwarder.java
+++ b/src/org/traccar/notification/EventForwarder.java
@@ -75,7 +75,7 @@ public final class EventForwarder {
             }
         }
         if (event.getGeofenceId() != 0) {
-            Geofence geofence = Context.getGeofenceManager().getGeofence(event.getGeofenceId());
+            Geofence geofence = (Geofence) Context.getGeofenceManager().getById(event.getGeofenceId());
             if (geofence != null) {
                 data.put(KEY_GEOFENCE, geofence);
             }
diff --git a/src/org/traccar/notification/NotificationFormatter.java b/src/org/traccar/notification/NotificationFormatter.java
index a30023fdc..cd9959671 100644
--- a/src/org/traccar/notification/NotificationFormatter.java
+++ b/src/org/traccar/notification/NotificationFormatter.java
@@ -51,7 +51,7 @@ public final class NotificationFormatter {
             velocityContext.put("speedUnits", ReportUtils.getSpeedUnit(userId));
         }
         if (event.getGeofenceId() != 0) {
-            velocityContext.put("geofence", Context.getGeofenceManager().getGeofence(event.getGeofenceId()));
+            velocityContext.put("geofence", Context.getGeofenceManager().getById(event.getGeofenceId()));
         }
         String driverUniqueId = event.getString(Position.KEY_DRIVER_UNIQUE_ID);
         if (driverUniqueId != null) {
diff --git a/src/org/traccar/notification/PropertiesProvider.java b/src/org/traccar/notification/PropertiesProvider.java
index e7cac8d0f..2fea901af 100644
--- a/src/org/traccar/notification/PropertiesProvider.java
+++ b/src/org/traccar/notification/PropertiesProvider.java
@@ -16,27 +16,27 @@
 package org.traccar.notification;
 
 import org.traccar.Config;
-import org.traccar.model.Extensible;
+import org.traccar.model.ExtendedModel;
 
 public class PropertiesProvider {
 
     private Config config;
 
-    private Extensible extensible;
+    private ExtendedModel extendedModel;
 
     public PropertiesProvider(Config config) {
         this.config = config;
     }
 
-    public PropertiesProvider(Extensible extensible) {
-        this.extensible = extensible;
+    public PropertiesProvider(ExtendedModel extendedModel) {
+        this.extendedModel = extendedModel;
     }
 
     public String getString(String key) {
         if (config != null) {
             return config.getString(key);
         } else {
-            return extensible.getString(key);
+            return extendedModel.getString(key);
         }
     }
 
diff --git a/src/org/traccar/processing/ComputedAttributesHandler.java b/src/org/traccar/processing/ComputedAttributesHandler.java
index 536e39ec4..d6a762535 100644
--- a/src/org/traccar/processing/ComputedAttributesHandler.java
+++ b/src/org/traccar/processing/ComputedAttributesHandler.java
@@ -86,8 +86,8 @@ public class ComputedAttributesHandler extends BaseDataHandler {
 
     @Override
     protected Position handlePosition(Position position) {
-        Collection<Attribute> attributes = Context.getAttributesManager().getAttributes(
-                Context.getAttributesManager().getAllDeviceAttributes(position.getDeviceId()));
+        Collection<Attribute> attributes = Context.getAttributesManager().getItems(Attribute.class,
+                Context.getAttributesManager().getAllDeviceItems(position.getDeviceId()));
         for (Attribute attribute : attributes) {
             if (attribute.getAttribute() != null) {
                 Object result = null;
diff --git a/src/org/traccar/reports/Events.java b/src/org/traccar/reports/Events.java
index 0706f1382..3a111944c 100644
--- a/src/org/traccar/reports/Events.java
+++ b/src/org/traccar/reports/Events.java
@@ -50,7 +50,7 @@ public final class Events {
             for (Event event : events) {
                 if (all || types.contains(event.getType())) {
                     long geofenceId = event.getGeofenceId();
-                    if (geofenceId == 0 || Context.getGeofenceManager().checkGeofence(userId, geofenceId)) {
+                    if (geofenceId == 0 || Context.getGeofenceManager().checkItemPermission(userId, geofenceId)) {
                        result.add(event);
                     }
                 }
@@ -74,8 +74,8 @@ public final class Events {
                 if (all || types.contains(event.getType())) {
                     long geofenceId = event.getGeofenceId();
                     if (geofenceId != 0) {
-                        if (Context.getGeofenceManager().checkGeofence(userId, geofenceId)) {
-                            Geofence geofence = Context.getGeofenceManager().getGeofence(geofenceId);
+                        if (Context.getGeofenceManager().checkItemPermission(userId, geofenceId)) {
+                            Geofence geofence = (Geofence) Context.getGeofenceManager().getById(geofenceId);
                             if (geofence != null) {
                                 geofenceNames.put(geofenceId, geofence.getName());
                             }