Add FlowIdGenerator's implementation class.

- Updated FlowId to use long internally
- Implemented FlowIdGeneratorWithIdBlockAllocator class as an implementation class of FlowIdGenerator.

Change-Id: Id3bcb47c63217b0ea4a2f7d5ae208532783c323a
diff --git a/src/test/java/net/onrc/onos/core/newintent/SingleSrcTreeFlowIntentTest.java b/src/test/java/net/onrc/onos/core/newintent/SingleSrcTreeFlowIntentTest.java
index 3330e47..cfd9391 100644
--- a/src/test/java/net/onrc/onos/core/newintent/SingleSrcTreeFlowIntentTest.java
+++ b/src/test/java/net/onrc/onos/core/newintent/SingleSrcTreeFlowIntentTest.java
@@ -25,8 +25,8 @@
 
     private final IntentId intentId1 = new IntentId(1L);
     private final IntentId intentId2 = new IntentId(2L);
-    private final FlowId flowId1 = new FlowId("tree1");
-    private final FlowId flowId2 = new FlowId("tree2");
+    private final FlowId flowId1 = new FlowId(1L);
+    private final FlowId flowId2 = new FlowId(2L);
     private final Dpid dpid1 = new Dpid(1);
     private final Dpid dpid2 = new Dpid(2);
     private final Dpid dpid3 = new Dpid(3);