Adding device type

Adding device type on port(eg Ethernet Port,TPort,WPort), Link(Ethernet,Optical..) and Switch(Ethernet,Optical)
Updated Serializers.
Fixed javadoc issue for Enums.

ONOS-1428

Change-Id: Id3e3094f1fbf90154fff9a61e3c0ca36be69c281
diff --git a/src/main/java/net/onrc/onos/core/topology/PortType.java b/src/main/java/net/onrc/onos/core/topology/PortType.java
new file mode 100644
index 0000000..6b5e6ca
--- /dev/null
+++ b/src/main/java/net/onrc/onos/core/topology/PortType.java
@@ -0,0 +1,18 @@
+package net.onrc.onos.core.topology;
+
+public enum PortType {
+    /**
+     *  Ethernet port is a port on Ethernet Switch.
+     */
+    ETHERNET_PORT,
+    /**
+     * WDM port is port connecting two Optical Switches,
+     * WDM port is only connected to another WDM port.
+     */
+    WDM_PORT,
+    /**
+     * Transponder port is a port on Optical Switch, which will be connected to Packet/Ethernet Switch.
+     * Transponder port is connected to Ethernet port.
+     */
+    TRANSPONDER_PORT;
+}