Merge pull request #3373 from Abyss777/refactor_managers

Refactor managers, permissions etc

11 files changed, 506 insertions, 1185 deletions

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;
+    }
+
+}