1 files changed, 74 insertions, 0 deletions
diff --git a/src/org/traccar/database/DataCache.java b/src/org/traccar/database/DataCache.java
new file mode 100644
index 000000000..f5aa3b1e9
--- /dev/null
+++ b/src/org/traccar/database/DataCache.java
@@ -0,0 +1,74 @@
+/*
+ * Copyright 2015 Anton Tananaev (anton.tananaev@gmail.com)
+ *
+ * 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.util.Collection;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+import org.traccar.model.Position;
+
+public class DataCache {
+    
+    private final Map<Long, Position> positions = new HashMap<Long, Position>();
+    private final Map<Long, Set<DataCacheListener>> listeners = new HashMap<Long, Set<DataCacheListener>>();
+    
+    public DataCache(DataManager dataManager) {
+        // TODO: load latest data from datavase
+    }
+    
+    public void update(Position position) {
+        long device = position.getDeviceId();
+        positions.put(device, position);
+        if (listeners.containsKey(device)) {
+            for (DataCacheListener listener : listeners.get(device)) {
+                listener.onUpdate(position);
+            }
+        }
+    }
+    
+    public static interface DataCacheListener {
+        public void onUpdate(Position position);
+    }
+    
+    public void addListener(Collection<Long> devices, DataCacheListener listener) {
+        for (long device : devices) {
+            addListener(device, listener);
+        }
+    }
+    
+    public void addListener(long device, DataCacheListener listener) {
+        if (!listeners.containsKey(device)) {
+            listeners.put(device, new HashSet<DataCacheListener>());
+        }
+        listeners.get(device).add(listener);
+    }
+    
+    public void removeListener(Collection<Long> devices, DataCacheListener listener) {
+        for (long device : devices) {
+            removeListener(device, listener);
+        }
+    }
+    
+    public void removeListener(long device, DataCacheListener listener) {
+        if (!listeners.containsKey(device)) {
+            listeners.put(device, new HashSet<DataCacheListener>());
+        }
+        listeners.get(device).remove(listener);
+    }
+    
+}