/*
* Copyright (C) 2005-2008 Jive Software. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.jivesoftware.openfire.cluster;
/**
* Listener for cluster events. Use {@link ClusterManager#addListener(ClusterEventListener)}
* to add new listeners.
*
* @author Gaston Dombiak
*/
public interface ClusterEventListener {
/**
* Notification event indicating that this JVM is now part of a cluster. At this point the
* {@link org.jivesoftware.openfire.XMPPServer#getNodeID()} holds the new nodeID value.
*
* <p>When joining the cluster as the senior cluster member the {@link #markedAsSeniorClusterMember()}
* event will be sent right after this event.</p>
*
* <p>At this point the CacheFactory holds clustered caches. That means that modifications
* to the caches will be reflected in the cluster. The clustered caches were just
* obtained from the cluster and no local cached data was automatically moved.</p>
*/
void joinedCluster();
/**
* Notification event indicating that another JVM is now part of a cluster.<p>
*
* At this point the CacheFactory of the new node holds clustered caches. That means
* that modifications to the caches of this JVM will be reflected in the cluster and
* in particular in the new node.
*
* @param nodeID ID of the node that joined the cluster.
*/
void joinedCluster(byte[] nodeID);
/**
* Notification event indicating that this JVM is no longer part of the cluster. This could
* happen when disabling clustering support, removing the enterprise plugin that provides
* clustering support or connection to cluster got lost.<p>
*
* Moreover, if we were in a "split brain" scenario (ie. separated cluster islands) and the
* island were this JVM belonged was marked as "old" then all nodes of that island will
* get the <tt>left cluster event</tt> and <tt>joined cluster events</tt>. That means that
* caches will be reset and thus will need to be repopulated again with fresh data from this JVM.
* This also includes the case where this JVM was the senior cluster member and when the islands
* met again then this JVM stopped being the senior member.<p>
*
* At this point the CacheFactory holds local caches. That means that modifications to
* the caches will only affect this JVM.
*/
void leftCluster();
/**
* Notification event indicating that another JVM is no longer part of the cluster. This could
* happen when disabling clustering support, removing the enterprise plugin that provides
* clustering support or connection to cluster got lost.<p>
*
* Moreover, if we were in a "split brain" scenario (ie. separated cluster islands) and the
* island were the other JVM belonged was marked as "old" then all nodes of that island will
* get the <tt>left cluster event</tt> and <tt>joined cluster events</tt>. That means that
* caches will be reset and thus will need to be repopulated again with fresh data from this JVM.
* This also includes the case where the other JVM was the senior cluster member and when the islands
* met again then the other JVM stopped being the senior member.<p>
*
* At this point the CacheFactory of the leaving node holds local caches. That means that modifications to
* the caches of this JVM will not affect the leaving node but other cluster members.
*
* @param nodeID ID of the node that is left the cluster.
*/
void leftCluster(byte[] nodeID);
/**
* Notification event indicating that this JVM is now the senior cluster member. This
* could either happen when initially joining the cluster or when the senior cluster
* member node left the cluster and this JVM was marked as the new senior cluster member.<p>
*
* Moreover, in the case of a "split brain" scenario (ie. separated cluster islands) each
* island will have its own senior cluster member. However, when the islands meet again there
* could only be one senior cluster member so one of the senior cluster members will stop playing
* that role. When that happens the JVM no longer playing that role will receive the
* {@link #leftCluster()} and {@link #joinedCluster()} events.
*/
void markedAsSeniorClusterMember();
}