Implement event listeners of the FlowManager.

- This commit adds two types of event objects: FlowBatchStateChangedEvent and FlowStatesChangedEvent.
- Listeners for these objects are defined by FlowManagerListener interface.
- FlowBatchStateChangedEvent notifies state changes of the flow batch operation.
 -- The state is defined by FlowBatchState.
- FlowStatesChangedEvent notifies state changes of the set of Flow objects.
 -- The state is defined by FlowState.
- This task is a part of ONOS-1739.

Change-Id: Ie8b3bb1c58dbe6bc608936e4a269e1de12dee96c
diff --git a/src/main/java/net/onrc/onos/api/flowmanager/FlowManagerService.java b/src/main/java/net/onrc/onos/api/flowmanager/FlowManagerService.java
index b8e14f4..4812de2 100644
--- a/src/main/java/net/onrc/onos/api/flowmanager/FlowManagerService.java
+++ b/src/main/java/net/onrc/onos/api/flowmanager/FlowManagerService.java
@@ -1,7 +1,6 @@
 package net.onrc.onos.api.flowmanager;
 
 import java.util.Collection;
-import java.util.EventListener;
 
 /**
  * An interface class for flow manager. The role of the flow manager is to
@@ -71,14 +70,14 @@
     /**
      * Adds event listener to this service.
      *
-     * @param listener EventListener to be added
+     * @param listener the listener to be added
      */
-    void addEventListener(EventListener listener);
+    void addListener(FlowManagerListener listener);
 
     /**
      * Removes event listener from this service.
      *
-     * @param listener EventListener to be removed
+     * @param listener the listener to be removed
      */
-    void removeEventListener(EventListener listener);
+    void removeListener(FlowManagerListener listener);
 }