Tomcat example source code file (ClusterListener.java)

This example Tomcat source code file (ClusterListener.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Tomcat tags/keywords

catalinacluster, catalinacluster, channellistener, clusterlistener, clusterlistener, clustermessage, clustermessage, io, member, member, stringmanager

The Tomcat ClusterListener.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.catalina.ha;




import java.io.Serializable;

import org.apache.catalina.tribes.ChannelListener;
import org.apache.catalina.tribes.Member;
import org.apache.catalina.util.StringManager;


/**
 * Receive SessionID cluster change from other backup node after primary session
 * node is failed.
 * 
 * @author Peter Rossbach
 * @author Filip Hanik
 * @version $Revision: 467222 $ $Date: 2006-10-24 05:17:11 +0200 (mar., 24 oct. 2006) $
 */
public abstract class ClusterListener implements ChannelListener {

    public static org.apache.juli.logging.Log log = org.apache.juli.logging.LogFactory.getLog(ClusterListener.class);


    //--Instance Variables--------------------------------------

    /**
     * The string manager for this package.
     */
    protected StringManager sm = StringManager.getManager(Constants.Package);

    protected CatalinaCluster cluster = null;

    //--Constructor---------------------------------------------

    public ClusterListener() {
    }
    
    //--Instance Getters/Setters--------------------------------
    
    public CatalinaCluster getCluster() {
        return cluster;
    }

    public void setCluster(CatalinaCluster cluster) {
        if (log.isDebugEnabled()) {
            if (cluster != null)
                log.debug("add ClusterListener " + this.toString() + " to cluster" + cluster);
            else
                log.debug("remove ClusterListener " + this.toString() + " from cluster");
        }
        this.cluster = cluster;
    }

    public boolean equals(Object listener) {
        return super.equals(listener);
    }

    public int hashCode() {
        return super.hashCode();
    }

    //--Logic---------------------------------------------------

    public final void messageReceived(Serializable msg, Member member) {
        if ( msg instanceof ClusterMessage ) messageReceived((ClusterMessage)msg);
    }
    public final boolean accept(Serializable msg, Member member) {
        if ( msg instanceof ClusterMessage ) return true;
        return false;
    }



    /**
     * Callback from the cluster, when a message is received, The cluster will
     * broadcast it invoking the messageReceived on the receiver.
     * 
     * @param msg
     *            ClusterMessage - the message received from the cluster
     */
    public abstract void messageReceived(ClusterMessage msg) ;
    

    /**
     * Accept only SessionIDMessages
     * 
     * @param msg
     *            ClusterMessage
     * @return boolean - returns true to indicate that messageReceived should be
     *         invoked. If false is returned, the messageReceived method will
     *         not be invoked.
     */
    public abstract boolean accept(ClusterMessage msg) ;

}