Tomcat example source code file (JvmRouteSessionIDBinderListener.java)

This example Tomcat source code file (JvmRouteSessionIDBinderListener.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

clusterlistener, container, container, context, io, ioexception, jvmroutesessionidbinderlistener, lifecycleexception, lifecycleexception, session, sessionidmessage, sessionidmessage, standardengine, string, string

The Tomcat JvmRouteSessionIDBinderListener.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.session;

import java.io.IOException;

import org.apache.catalina.Container;
import org.apache.catalina.Context;
import org.apache.catalina.Engine;
import org.apache.catalina.LifecycleException;
import org.apache.catalina.Session;
import org.apache.catalina.ha.ClusterMessage;
import org.apache.catalina.core.StandardEngine;
import org.apache.catalina.ha.*;

/**
 * Receive SessionID cluster change from other backup node after primary session
 * node is failed.
 * 
 * @author Peter Rossbach
 * @version $Revision: 467222 $ $Date: 2006-10-24 05:17:11 +0200 (mar., 24 oct. 2006) $
 */
public class JvmRouteSessionIDBinderListener extends ClusterListener {
 
    /**
     * The descriptive information about this implementation.
     */
    protected static final String info = "org.apache.catalina.ha.session.JvmRouteSessionIDBinderListener/1.1";

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


    protected boolean started = false;

    /**
     * number of session that goes to this cluster node
     */
    private long numberOfSessions = 0;

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

    public JvmRouteSessionIDBinderListener() {
    }

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

    /**
     * Return descriptive information about this implementation.
     */
    public String getInfo() {

        return (info);

    }

    /**
     * @return Returns the numberOfSessions.
     */
    public long getNumberOfSessions() {
        return numberOfSessions;
    }

    /**
     * Add this Mover as Cluster Listener ( receiver)
     * 
     * @throws LifecycleException
     */
    public void start() throws LifecycleException {
        if (started)
            return;
        getCluster().addClusterListener(this);
        started = true;
        if (log.isInfoEnabled())
            log.info(sm.getString("jvmRoute.clusterListener.started"));
    }

    /**
     * Remove this from Cluster Listener
     * 
     * @throws LifecycleException
     */
    public void stop() throws LifecycleException {
        started = false;
        getCluster().removeClusterListener(this);
        if (log.isInfoEnabled())
            log.info(sm.getString("jvmRoute.clusterListener.stopped"));
    }

    /**
     * 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 void messageReceived(ClusterMessage msg) {
        if (msg instanceof SessionIDMessage && msg != null) {
            SessionIDMessage sessionmsg = (SessionIDMessage) msg;
            if (log.isDebugEnabled())
                log.debug(sm.getString(
                        "jvmRoute.receiveMessage.sessionIDChanged", sessionmsg
                                .getOrignalSessionID(), sessionmsg
                                .getBackupSessionID(), sessionmsg
                                .getContextPath()));
            Container container = getCluster().getContainer();
            Container host = null ;
            if(container instanceof Engine) {
                host = container.findChild(sessionmsg.getHost());
            } else {
                host = container ;
            }
            if (host != null) {
                Context context = (Context) host.findChild(sessionmsg
                        .getContextPath());
                if (context != null) {
                    try {
                        Session session = context.getManager().findSession(
                                sessionmsg.getOrignalSessionID());
                        if (session != null) {
                            session.setId(sessionmsg.getBackupSessionID());
                        } else if (log.isInfoEnabled())
                            log.info(sm.getString("jvmRoute.lostSession",
                                    sessionmsg.getOrignalSessionID(),
                                    sessionmsg.getContextPath()));
                    } catch (IOException e) {
                        log.error(e);
                    }

                } else if (log.isErrorEnabled())
                    log.error(sm.getString("jvmRoute.contextNotFound",
                            sessionmsg.getContextPath(), ((StandardEngine) host
                                    .getParent()).getJvmRoute()));
            } else if (log.isErrorEnabled())
                log.error(sm.getString("jvmRoute.hostNotFound", sessionmsg.getContextPath()));
        }
        return;
    }

    /**
     * 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 boolean accept(ClusterMessage msg) {
        return (msg instanceof SessionIDMessage);
    }
}