Define the new Intent Framework APIs (Intent Service)

- Define the base Intent class and sub-classes required in SDN-IP
- IntentService provides the APIs for application developers
- IntentExtensionService enables to define application specific intent types
- Provide event handling mechanism via IntentEventListener

This is for ONOS-1654.

Change-Id: Id1705f1fbc1acd4862b33fd9ab97aafe2e84a685
diff --git a/src/main/java/net/onrc/onos/api/newintent/IntentEventListener.java b/src/main/java/net/onrc/onos/api/newintent/IntentEventListener.java
new file mode 100644
index 0000000..6d8bda2
--- /dev/null
+++ b/src/main/java/net/onrc/onos/api/newintent/IntentEventListener.java
@@ -0,0 +1,13 @@
+package net.onrc.onos.api.newintent;
+
+/**
+ * Listener for {@link IntentEvent intent events}.
+ */
+public interface IntentEventListener {
+    /**
+     * Processes the specified intent event.
+     *
+     * @param event the event to process
+     */
+    void event(IntentEvent event);
+}