ONOS-1871: Send Topology MastershipEvent info to Topology listeners.
The MastershipEvent info is needed by applications such as the GUI
(via the Websocket client).
NOTE: Previously, the Mastership Events were sent only when there
was any change, but no Mastership Events were sent when a listener
has just subscribed.
The solution is to add a mechanism for creating and sending Topology
Snapshot event to new listeners, and that event also includes
the Mastership Events.
The modifications are:
* Renamed and updated the ITopologyService API for adding/removing
Topology listeners:
OLD: registerTopologyListener() and deregisterTopologyListener()
NEW: addListener() and removeListener()
Also, addListener() has a second argument:
"boolean startFromSnapshot"
If that argument is true, and if the topology is not empty, the first
(expected) event to that listener should be a snapshot of the current
topology.
* Added TopologyEvents() constructor for ADDED events only. Such event
can be used to represent a snapshot of the topology.
* Added new APIs to TopologyInternal:
getAllSwitchEvents(), getAllPortEvents(), get AllLinkEvents(),
getAllHostEvents()
Those APIs are needed for creating a snapshot of the topology.
* Added a mechanism for creating empty (NO-OP) TopologyEvent instance,
and use that mechanism to "wake-up" the EventHandler processing thread
when it needs to send Topology Snapshot to a new listener.
This solution is (kind-of) a hack.
Change-Id: Ie1eb52242f58682aac61f54af29c3b5d291ac0bd
diff --git a/src/main/java/net/onrc/onos/core/topology/ITopologyService.java b/src/main/java/net/onrc/onos/core/topology/ITopologyService.java
index b6280bc..7ab5c47 100644
--- a/src/main/java/net/onrc/onos/core/topology/ITopologyService.java
+++ b/src/main/java/net/onrc/onos/core/topology/ITopologyService.java
@@ -14,19 +14,22 @@
public Topology getTopology();
/**
- * Registers a listener for topology events.
+ * Adds a listener for topology events.
*
- * @param listener the listener to register
+ * @param listener the listener to add.
+ * @param startFromSnapshot if true, and if the topology is not
+ * empty, the first event should be a snapshot of the current topology.
*/
- public void registerTopologyListener(ITopologyListener listener);
+ public void addListener(ITopologyListener listener,
+ boolean startFromSnapshot);
/**
- * Deregisters a listener for topology events. The listener will no longer
+ * Removes a listener for topology events. The listener will no longer
* receive topology events after this call.
*
- * @param listener the listener to deregister
+ * @param listener the listener to remove.
*/
- public void deregisterTopologyListener(ITopologyListener listener);
+ public void removeListener(ITopologyListener listener);
/**
* Allows a module to get a reference to the southbound interface to