Rename Port to PortNumber

Current util.Port actually only represent a port number.
Renaming it to PortNumber, so that it matches what it actually reprsent.

- Updated javadoc
- Removed unnecessary hashCode calculation
- Hide default constructor from public

Change-Id: Ib26c746eaa27464356c4ca0abff6af5e321afc35
diff --git a/src/main/java/net/onrc/onos/core/util/SwitchPort.java b/src/main/java/net/onrc/onos/core/util/SwitchPort.java
index edb9f77..b3ed985 100644
--- a/src/main/java/net/onrc/onos/core/util/SwitchPort.java
+++ b/src/main/java/net/onrc/onos/core/util/SwitchPort.java
@@ -8,7 +8,7 @@
  */
 public final class SwitchPort {
     private final Dpid dpid;        // The DPID of the switch
-    private final Port port;        // The port of the switch
+    private final PortNumber port;        // The port of the switch
 
     /**
      * Default constructor.
@@ -24,7 +24,7 @@
      * @param dpid the DPID to use.
      * @param port the port to use.
      */
-    public SwitchPort(Dpid dpid, Port port) {
+    public SwitchPort(Dpid dpid, PortNumber port) {
         this.dpid = dpid;
         this.port = port;
     }
@@ -37,7 +37,7 @@
      */
     public SwitchPort(long dpid, short port) {
         this.dpid = new Dpid(dpid);
-        this.port = new Port(port);
+        this.port = new PortNumber(port);
     }
 
     /**
@@ -56,7 +56,7 @@
      * @return the port value of the Switch-Port.
      */
     @JsonProperty("port")
-    public Port port() {
+    public PortNumber port() {
         return port;
     }