Setup Json Serializers for Topology classes.
Add the appropriate annotation to specify the Json serializer for each
class; Device, Link, Port, Switch

Change-Id: I83fd36afc2ae58c7fef4e928ee0081f89c5d4c98
diff --git a/src/main/java/net/onrc/onos/core/topology/Port.java b/src/main/java/net/onrc/onos/core/topology/Port.java
index 9a0c06e..a5f9a20 100644
--- a/src/main/java/net/onrc/onos/core/topology/Port.java
+++ b/src/main/java/net/onrc/onos/core/topology/Port.java
@@ -1,6 +1,8 @@
 package net.onrc.onos.core.topology;
 
+import net.onrc.onos.core.topology.serializers.PortSerializer;
 import net.onrc.onos.core.util.SwitchPort;
+import org.codehaus.jackson.map.annotate.JsonSerialize;
 
 //TODO Everything returned by these interfaces must be either Unmodifiable view,
 //immutable object, or a copy of the original "SB" In-memory Topology.
@@ -8,6 +10,7 @@
 /**
  * Interface of Port object in the topology.
  */
+@JsonSerialize(using = PortSerializer.class)
 public interface Port {
 
     /**