ONOS-5503 Added CLIs for administering OFAgent

Change-Id: I58256316e2054952da9dce04bf927901761807e5
diff --git a/apps/ofagent/src/main/java/org/onosproject/ofagent/api/OFAgent.java b/apps/ofagent/src/main/java/org/onosproject/ofagent/api/OFAgent.java
index 0db4489..659d6db 100644
--- a/apps/ofagent/src/main/java/org/onosproject/ofagent/api/OFAgent.java
+++ b/apps/ofagent/src/main/java/org/onosproject/ofagent/api/OFAgent.java
@@ -71,6 +71,15 @@
          */
         OFAgent build();
 
+
+        /**
+         * Returns OF agent builder with the supplied OF agent.
+         *
+         * @param ofAgent ofagent
+         * @return of agent builder
+         */
+        Builder from(OFAgent ofAgent);
+
         /**
          * Returns OF agent builder with the supplied network ID.
          *
@@ -88,6 +97,22 @@
         Builder controllers(Set<OFController> controllers);
 
         /**
+         * Returns OF agent builder with the supplied additional controller.
+         *
+         * @param controller additional controller
+         * @return of agent builder
+         */
+        Builder addController(OFController controller);
+
+        /**
+         * Returns OF agent builder with the supplied controller removed.
+         *
+         * @param controller controller to delete
+         * @return of agent builder
+         */
+        Builder deleteController(OFController controller);
+
+        /**
          * Returns OF agent builder with the supplied state.
          *
          * @param state state of the agent
diff --git a/apps/ofagent/src/main/java/org/onosproject/ofagent/api/OFAgentAdminService.java b/apps/ofagent/src/main/java/org/onosproject/ofagent/api/OFAgentAdminService.java
index 0c6667a..859215d 100644
--- a/apps/ofagent/src/main/java/org/onosproject/ofagent/api/OFAgentAdminService.java
+++ b/apps/ofagent/src/main/java/org/onosproject/ofagent/api/OFAgentAdminService.java
@@ -40,8 +40,9 @@
      * Removes the OpenFlow agent for the given virtual network.
      *
      * @param networkId virtual network identifier
+     * @return removed ofagent; null if it fails
      */
-    void removeAgent(NetworkId networkId);
+    OFAgent removeAgent(NetworkId networkId);
 
     /**
      * Starts the agent for the given network.