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/TopologyImpl.java b/src/main/java/net/onrc/onos/core/topology/TopologyImpl.java
index d79d204..fcf3caa 100644
--- a/src/main/java/net/onrc/onos/core/topology/TopologyImpl.java
+++ b/src/main/java/net/onrc/onos/core/topology/TopologyImpl.java
@@ -282,7 +282,7 @@
             if (link == null) {
                 continue;
             }
-            if (link.getDstPort().asSwitchPort().equals(dstSwitchPort)) {
+            if (link.getDstPort().getSwitchPort().equals(dstSwitchPort)) {
                 return link;
             }
         }