Define ID representation for Intent, IFlow and MatchAction

- Defines BatchOperationTargetId abstract class.
- The above class is the base class of IntentId, FlowId, and MatchActionId.
 -- Intent objects use IntentId class for its ID.
 -- IFlow objects use FlowId class for its ID.
 -- MatchAction objects use MatchActionId class for its ID.
- BatchOperation classes requires the BatchOperationTargetId as the target object's ID.
- This work is a part of ONOS-1758.

Change-Id: I71bb4e6acd3836d1ced3beb6fb331bca451abdc3
diff --git a/src/main/java/net/onrc/onos/api/intent/IIntentRuntimeService.java b/src/main/java/net/onrc/onos/api/intent/IIntentRuntimeService.java
index 5e9ed52..2b8774b 100644
--- a/src/main/java/net/onrc/onos/api/intent/IIntentRuntimeService.java
+++ b/src/main/java/net/onrc/onos/api/intent/IIntentRuntimeService.java
@@ -32,7 +32,7 @@
      * @param id ID of the intent to be removed.
      * @return true if succeeded, false otherwise.
      */
-    boolean removeIntent(String id);
+    boolean removeIntent(IntentId id);
 
     /**
      * Overwrites existing intent by new specified intent.
@@ -41,7 +41,7 @@
      * @param intent The new intent to be added.
      * @return true if succeeded, false otherwise.
      */
-    boolean updateIntent(String id, Intent intent);
+    boolean updateIntent(IntentId id, Intent intent);
 
     /**
      * Gets specific intent.
@@ -49,7 +49,7 @@
      * @param id ID of the intent should be retrieved
      * @return Intent if it exists, null otherwise.
      */
-    Intent getIntent(String id);
+    Intent getIntent(IntentId id);
 
     /**
      * Gets all intents.
diff --git a/src/main/java/net/onrc/onos/api/intent/Intent.java b/src/main/java/net/onrc/onos/api/intent/Intent.java
index 93d6459..048bdee 100644
--- a/src/main/java/net/onrc/onos/api/intent/Intent.java
+++ b/src/main/java/net/onrc/onos/api/intent/Intent.java
@@ -20,7 +20,7 @@
  * data-plane to satisfy those constraints.
  */
 public abstract class Intent implements IBatchOperationTarget {
-    protected String id;
+    protected final IntentId id;
 
     /**
      * Constructor.
@@ -28,7 +28,7 @@
      * @param id ID for this Intent object.
      */
     public Intent(String id) {
-        this.id = id;
+        this.id = new IntentId(id);
     }
 
     /**
@@ -37,7 +37,7 @@
      * @return ID for this Intent object.
      */
     @Override
-    public String getId() {
+    public IntentId getId() {
         return id;
     }
 
diff --git a/src/main/java/net/onrc/onos/api/intent/IntentId.java b/src/main/java/net/onrc/onos/api/intent/IntentId.java
new file mode 100644
index 0000000..d488183
--- /dev/null
+++ b/src/main/java/net/onrc/onos/api/intent/IntentId.java
@@ -0,0 +1,30 @@
+package net.onrc.onos.api.intent;
+
+import net.onrc.onos.api.batchoperation.BatchOperationTargetId;
+
+public class IntentId extends BatchOperationTargetId {
+    private final String value;
+
+    public IntentId(String id) {
+        value = id;
+    }
+
+    @Override
+    public String toString() {
+        return value;
+    }
+
+    @Override
+    public int hashCode() {
+        return value.hashCode();
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj instanceof IntentId) {
+            IntentId other = (IntentId) obj;
+            return (this.value.equals(other.value));
+        }
+        return false;
+    }
+}