ONOS-6626 OFAgent - handle StatsRequest, GetConfigRequest and SetConfigMessage

Change-Id: Ie6744c7846c41024173049d2094260ea571844b3
diff --git a/apps/ofagent/src/main/java/org/onosproject/ofagent/api/OFSwitchOperationService.java b/apps/ofagent/src/main/java/org/onosproject/ofagent/api/OFSwitchOperationService.java
index 6413cba..6e2f5ad 100644
--- a/apps/ofagent/src/main/java/org/onosproject/ofagent/api/OFSwitchOperationService.java
+++ b/apps/ofagent/src/main/java/org/onosproject/ofagent/api/OFSwitchOperationService.java
@@ -126,4 +126,28 @@
      * @param msg     echo request message
      */
     void processEchoRequest(Channel channel, OFMessage msg);
+
+    /**
+     * Processes GetConfig request from the controllers.
+     *
+     * @param channel received channel
+     * @param msg     GetConfig request message
+     */
+    void processGetConfigRequest(Channel channel, OFMessage msg);
+
+    /**
+     * Processes SetConfig message from the controllers.
+     *
+     * @param channel received channel
+     * @param msg     SetConfig message
+     */
+    void processSetConfigMessage(Channel channel, OFMessage msg);
+
+    /**
+     * Processes barrier request from the controllers.
+     *
+     * @param channel received channel
+     * @param msg     barrier request message
+     */
+    void processBarrierRequest(Channel channel, OFMessage msg);
 }