Add new method FlowEntry.isValidFlowId() and the corresponding unit test.
diff --git a/src/main/java/net/onrc/onos/ofcontroller/util/FlowEntry.java b/src/main/java/net/onrc/onos/ofcontroller/util/FlowEntry.java
index 9862040..03794a1 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/util/FlowEntry.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/util/FlowEntry.java
@@ -116,6 +116,7 @@
 
     /**
      * Get the Flow ID.
+     *
      * @return the Flow ID.
      */
     @JsonIgnore
@@ -131,6 +132,17 @@
     }
 
     /**
+     * Test whether the Flow ID is valid.
+     *
+     * @return true if the Flow ID is valid, otherwise false.
+     */
+    public boolean isValidFlowId() {
+	if (this.flowId == null)
+	    return false;
+	return (this.flowId.value() != 0);
+    }
+
+    /**
      * Get the Flow Entry ID.
      *
      * @return the Flow Entry ID.
diff --git a/src/test/java/net/onrc/onos/ofcontroller/util/FlowEntryTest.java b/src/test/java/net/onrc/onos/ofcontroller/util/FlowEntryTest.java
index 531fdb3..7385b25 100644
--- a/src/test/java/net/onrc/onos/ofcontroller/util/FlowEntryTest.java
+++ b/src/test/java/net/onrc/onos/ofcontroller/util/FlowEntryTest.java
@@ -149,6 +149,23 @@
 	}
 
 	@Test
+	public void testIsValidFlowId(){
+		FlowEntry e = new FlowEntry();
+
+		// Test a Flow Entry with empty Flow ID
+		assertEquals("isValidFlowId", false, e.isValidFlowId() );
+
+		// Test a Flow Entry with invalid Flow ID
+		e.setFlowId(new FlowId());
+		assertEquals("isValidFlowId", false, e.isValidFlowId() );
+
+		// Test a Flow Entry with valid Flow ID
+		e.setFlowId(new FlowId(0x1));
+		assertEquals("isValidFlowId", true, e.isValidFlowId() );
+		assertEquals("isValidFlowId", true, entry.isValidFlowId() );
+	}
+
+	@Test
 	public void testFlowEntryId(){
 		assertEquals("flowEntryId", flowEntryId, entry.flowEntryId() );
 	}