Added outline of the path taken through the NetworkGraph by an event generated from the discovery modules

Change-Id: Id875f54f522e3a9135e1a7e9a989167ca532a7a5
diff --git a/src/main/java/net/onrc/onos/ofcontroller/networkgraph/NetworkGraphDiscoveryInterface.java b/src/main/java/net/onrc/onos/ofcontroller/networkgraph/NetworkGraphDiscoveryInterface.java
new file mode 100644
index 0000000..a4d21a9
--- /dev/null
+++ b/src/main/java/net/onrc/onos/ofcontroller/networkgraph/NetworkGraphDiscoveryInterface.java
@@ -0,0 +1,16 @@
+package net.onrc.onos.ofcontroller.networkgraph;
+
+import java.net.InetAddress;
+import java.util.Set;
+
+public interface NetworkGraphDiscoveryInterface {
+	public void putSwitchEvent(SwitchEvent switchEvent);
+	public void removeSwitchEvent(SwitchEvent switchEvent);
+	public void putPortEvent(PortEvent portEvent);
+	public void removePortEvent(PortEvent portEvent);
+	public void putLinkEvent(LinkEvent linkEvent);
+	public void removeLinkEvent(LinkEvent linkEvent);
+	public void updateDeviceEvent(DeviceEvent deviceToUpdate, 
+			Set<InetAddress> updatedIpAddrs, Set<Port> updatedAttachmentPoints);
+	public void removeDeviceEvent(DeviceEvent deviceEvent);
+}