Cosmetic fixes

- Changed Port#{asSwitchPort() -> getSwitchPort()}
- Added   Port#getPortNumber()
- Changed some formal param names: e.g., number -> portNumber

Change-Id: If93043489591e43e189137ee2f82907e863fdada
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 50feb99..2e428c7 100644
--- a/src/main/java/net/onrc/onos/core/topology/Port.java
+++ b/src/main/java/net/onrc/onos/core/topology/Port.java
@@ -33,12 +33,19 @@
     public PortNumber getNumber();
 
     /**
+     * Gets the port number of this port.
+     *
+     * @return port number
+     */
+    public PortNumber getPortNumber();
+
+    /**
      * Gets a {@link SwitchPort} that represents this Port's dpid and port
      * number.
      *
      * @return a SwitchPort representing the Port
      */
-    public SwitchPort asSwitchPort();
+    public SwitchPort getSwitchPort();
 
     /**
      * Gets the hardware address of this port.