diff --git a/src/main/java/net/onrc/onos/core/topology/NetworkGraphDiscoveryInterface.java b/src/main/java/net/onrc/onos/core/topology/NetworkGraphDiscoveryInterface.java
index 14ef0ea..219417f 100644
--- a/src/main/java/net/onrc/onos/core/topology/NetworkGraphDiscoveryInterface.java
+++ b/src/main/java/net/onrc/onos/core/topology/NetworkGraphDiscoveryInterface.java
@@ -11,10 +11,10 @@
      * Switch discovered event.
      *
      * @param switchEvent the switch event.
-     * @param portEvents the corresponding port events for the switch.
+     * @param portEvents  the corresponding port events for the switch.
      */
     public void putSwitchDiscoveryEvent(SwitchEvent switchEvent,
-					Collection<PortEvent> portEvents);
+                                        Collection<PortEvent> portEvents);
 
     /**
      * Switch removed event.