Add a distributed map implementation of FlowMap.

- Added SharedFlowMap as an implementation of FlowMap.
- SharedFlowMap is a distributed map implementation based on ISharedCollectionsService.
- This task is a part of ONOS-1688 and ONOS-1736.

Change-Id: I57961c415636b480bbfb4b6c117530afc34b9b94
diff --git a/src/main/java/net/onrc/onos/core/flowmanager/SharedFlowMapEventDispatcher.java b/src/main/java/net/onrc/onos/core/flowmanager/SharedFlowMapEventDispatcher.java
new file mode 100644
index 0000000..cc41ce0
--- /dev/null
+++ b/src/main/java/net/onrc/onos/core/flowmanager/SharedFlowMapEventDispatcher.java
@@ -0,0 +1,125 @@
+package net.onrc.onos.core.flowmanager;
+
+import java.util.concurrent.CopyOnWriteArraySet;
+
+import net.onrc.onos.api.flowmanager.Flow;
+import net.onrc.onos.api.flowmanager.FlowId;
+import net.onrc.onos.api.flowmanager.FlowState;
+import net.onrc.onos.core.util.serializers.KryoFactory;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.hazelcast.core.EntryEvent;
+import com.hazelcast.core.EntryListener;
+import com.hazelcast.core.IMap;
+
+/**
+ * This class is used for managing listeners of the {@link SharedFlowMap}.
+ */
+class SharedFlowMapEventDispatcher implements EntryListener<String, byte[]> {
+    private CopyOnWriteArraySet<FlowMapEventListener> listeners;
+    private static final Logger log = LoggerFactory
+            .getLogger(SharedFlowMapEventDispatcher.class);
+
+    /**
+     * Creates dispatcher using flow map objects.
+     *
+     * @param flowMap the flow map object
+     * @param flowStateMap the flow state map object
+     */
+    SharedFlowMapEventDispatcher(IMap<String, byte[]> flowMap,
+            IMap<String, byte[]> flowStateMap) {
+        listeners = new CopyOnWriteArraySet<>();
+        flowMap.addEntryListener(this, true);
+        flowStateMap.addEntryListener(this, true);
+    }
+
+    /**
+     * Adds a listener for listening events related to the map.
+     *
+     * @param listener the {@link FlowMapEventListener} to be added
+     */
+    void addListener(FlowMapEventListener listener) {
+        listeners.add(listener);
+    }
+
+    /**
+     * Removes a listener for listening events related to the map.
+     *
+     * @param listener the {@link FlowMapEventListener} to be removed
+     */
+    void removeListener(FlowMapEventListener listener) {
+        listeners.remove(listener);
+    }
+
+    @Override
+    public void entryAdded(EntryEvent<String, byte[]> event) {
+        final Object value = KryoFactory.deserialize(event.getValue());
+        if (value instanceof Flow) {
+            // Handles events from flowMap.
+            final Flow flow = (Flow) value;
+            log.trace("Flow {} was added", flow);
+            for (FlowMapEventListener e : listeners) {
+                e.flowAdded(flow.getId(), flow);
+                e.flowStateChanged(flow.getId(), null, FlowState.SUBMITTED);
+            }
+        } else if (value instanceof FlowState) {
+            // Handles events from flowStateMap.
+            final FlowState state = (FlowState) value;
+            final FlowId id = new FlowId(Long.parseLong(event.getKey()));
+            log.trace("FlowState of FlowId {} was set to {}", id, state);
+            for (FlowMapEventListener e : listeners) {
+                e.flowStateChanged(id, FlowState.SUBMITTED, state);
+            }
+        } else {
+            throw new IllegalStateException("Added illegal value: " + value.toString());
+        }
+    }
+
+    @Override
+    public void entryRemoved(EntryEvent<String, byte[]> event) {
+        final Object value = KryoFactory.deserialize(event.getValue());
+        if (value instanceof Flow) {
+            // Handles events from flowMap.
+            final Flow flow = (Flow) value;
+            log.trace("Flow {} was removed", flow);
+            for (FlowMapEventListener e : listeners) {
+                e.flowRemoved(flow.getId());
+            }
+        } else if (value instanceof FlowState) {
+            // Handles events from flowStateMap.
+            log.trace("FlowState {} of FlowId {} was removed", value, event.getKey());
+        } else {
+            throw new IllegalStateException("Removed illegal value: " + value.toString());
+        }
+    }
+
+    @Override
+    public void entryUpdated(EntryEvent<String, byte[]> event) {
+        final Object value = KryoFactory.deserialize(event.getValue());
+        if (value instanceof Flow) {
+            // Handles events from flowMap.
+            log.trace("Flow Updated by {}", value);
+        } else if (value instanceof FlowState) {
+            // Handles events from flowStateMap.
+            Object oldValue = KryoFactory.deserialize(event.getOldValue());
+            final FlowState state = (FlowState) value;
+            final FlowState oldState = (FlowState) oldValue;
+            final FlowId id = new FlowId(Long.parseLong(event.getKey()));
+            log.trace("FlowState of FlowId {} was updated from {} to {}",
+                    id, oldState, state);
+            for (FlowMapEventListener e : listeners) {
+                e.flowStateChanged(id, oldState, state);
+            }
+        } else {
+            throw new IllegalStateException("Updated illegal value: " + value.toString());
+        }
+    }
+
+    @Override
+    public void entryEvicted(EntryEvent<String, byte[]> event) {
+        // do nothing.
+    }
+
+}