Add javadoc to Switch/Port/Link/ShortestPathIntent

Change-Id: I7a53a1e40f24650de37c885d46e42db9f5d4cc14
diff --git a/src/main/java/net/onrc/onos/core/topology/Link.java b/src/main/java/net/onrc/onos/core/topology/Link.java
index 2acf7dc..8715b12 100644
--- a/src/main/java/net/onrc/onos/core/topology/Link.java
+++ b/src/main/java/net/onrc/onos/core/topology/Link.java
@@ -1,42 +1,41 @@
 package net.onrc.onos.core.topology;
 
+// TODO Everything returned by these interfaces must be either Unmodifiable view,
+// immutable object, or a copy of the original "SB" In-memory Topology.
 /**
- * Interface of Link Object exposed to the "NB" read-only Topology.
- * <p/>
- * Everything returned by these interfaces must be either Unmodifiable view,
- * immutable object, or a copy of the original "SB" In-memory Topology.
+ * Interface of Link object in Network Graph topology.
  */
 public interface Link {
     /**
-     * Get the source switch for the link.
+     * Gets the source switch for the link.
      *
      * @return the source switch for the link.
      */
     public Switch getSrcSwitch();
 
     /**
-     * Get the source port for the link.
+     * Gets the source port for the link.
      *
      * @return the source port for the link.
      */
     public Port getSrcPort();
 
     /**
-     * Get the destination switch for the link.
+     * Gets the destination switch for the link.
      *
      * @return the destination switch for the link.
      */
     public Switch getDstSwitch();
 
     /**
-     * Get the destination port for the link.
+     * Gets the destination port for the link.
      *
      * @return the destination port for the link.
      */
     public Port getDstPort();
 
     /**
-     * Get the last seen time for the link.
+     * Gets the last seen time for the link.
      * <p/>
      * TODO: Not implemented yet.
      * TODO: what is the time definition?
@@ -46,7 +45,7 @@
     public long getLastSeenTime();
 
     /**
-     * Get the link cost.
+     * Gets the link cost.
      * <p/>
      * TODO: What is the unit?
      *
@@ -55,7 +54,7 @@
     public int getCost();
 
     /**
-     * Get the link capacity.
+     * Gets the link capacity.
      * <p/>
      * TODO: What is the unit?
      *