Tomcat example source code file (CometConnectionManagerValve.java)

This example Tomcat source code file (CometConnectionManagerValve.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

cometeventimpl, cometeventimpl, connectioninfo, connectioninfo, exception, http, io, ioexception, iterator, lifecycle, lifecycleexception, lifecycleexception, request, response, response, servlet, servletexception, string, string, threading

The Tomcat CometConnectionManagerValve.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.valves;


import java.io.IOException;
import java.util.Iterator;
import java.util.concurrent.ConcurrentHashMap;

import javax.servlet.ServletException;
import javax.servlet.http.HttpSession;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;

import org.apache.catalina.CometEvent;
import org.apache.catalina.Context;
import org.apache.catalina.Lifecycle;
import org.apache.catalina.LifecycleEvent;
import org.apache.catalina.LifecycleException;
import org.apache.catalina.LifecycleListener;
import org.apache.catalina.connector.CometEventImpl;
import org.apache.catalina.connector.Request;
import org.apache.catalina.connector.Response;
import org.apache.catalina.util.LifecycleSupport;
import org.apache.catalina.util.StringManager;


/**
 * <p>Implementation of a Valve that tracks Comet connections, and closes them
 * when the associated session expires or the webapp is reloaded.</p>
 *
 * <p>This Valve should be attached to a Context.

 *
 * @author Remy Maucherat
 * @version $Revision: 467222 $ $Date: 2006-10-24 05:17:11 +0200 (mar., 24 oct. 2006) $
 */

public class CometConnectionManagerValve
    extends ValveBase
    implements Lifecycle, HttpSessionListener, LifecycleListener {


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


    /**
     * The descriptive information related to this implementation.
     */
    protected static final String info =
        "org.apache.catalina.valves.CometConnectionManagerValve/1.0";


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


    /**
     * The lifecycle event support for this component.
     */
    protected LifecycleSupport lifecycle = new LifecycleSupport(this);


    /**
     * Has this component been started yet?
     */
    protected boolean started = false;

    
    /**
     * Connection list.
     */
    protected ConcurrentHashMap<String, ConnectionInfo[]> connections
        = new ConcurrentHashMap<String, ConnectionInfo[]>();
    

    // ------------------------------------------------------------- Properties

    
    // ------------------------------------------------------ Lifecycle Methods


    /**
     * Add a lifecycle event listener to this component.
     *
     * @param listener The listener to add
     */
    public void addLifecycleListener(LifecycleListener listener) {

        lifecycle.addLifecycleListener(listener);

    }


    /**
     * Get the lifecycle listeners associated with this lifecycle. If this
     * Lifecycle has no listeners registered, a zero-length array is returned.
     */
    public LifecycleListener[] findLifecycleListeners() {

        return lifecycle.findLifecycleListeners();

    }


    /**
     * Remove a lifecycle event listener from this component.
     *
     * @param listener The listener to add
     */
    public void removeLifecycleListener(LifecycleListener listener) {

        lifecycle.removeLifecycleListener(listener);

    }


    /**
     * Prepare for the beginning of active use of the public methods of this
     * component.  This method should be called after <code>configure(),
     * and before any of the public methods of the component are utilized.
     *
     * @exception LifecycleException if this component detects a fatal error
     *  that prevents this component from being used
     */
    public void start() throws LifecycleException {

        // Validate and update our current component state
        if (started)
            throw new LifecycleException
                (sm.getString("semaphoreValve.alreadyStarted"));
        lifecycle.fireLifecycleEvent(START_EVENT, null);
        started = true;

        if (container instanceof Context) {
            ((Lifecycle) container).addLifecycleListener(this);
        }
        
    }


    /**
     * Gracefully terminate the active use of the public methods of this
     * component.  This method should be the last one called on a given
     * instance of this component.
     *
     * @exception LifecycleException if this component detects a fatal error
     *  that needs to be reported
     */
    public void stop() throws LifecycleException {

        // Validate and update our current component state
        if (!started)
            throw new LifecycleException
                (sm.getString("semaphoreValve.notStarted"));
        lifecycle.fireLifecycleEvent(STOP_EVENT, null);
        started = false;

        if (container instanceof Context) {
            ((Lifecycle) container).removeLifecycleListener(this);
        }

        // The webapp is getting stopped, so all current connections 
        // should be closed
        // Close all Comet connections associated with this session
        // Note: this will only be done if the container was not a Context
        // (otherwise, this needs to be done before stop, as the servlet would
        // be deallocated already)
        Iterator<ConnectionInfo[]> iterator = connections.values().iterator();
        while (iterator.hasNext()) {
            ConnectionInfo[] connectionInfos = iterator.next();
            if (connectionInfos != null) {
                for (int i = 0; i < connectionInfos.length; i++) {
                    ConnectionInfo connectionInfo = connectionInfos[i];
                    try {
                        connectionInfo.event.close();
                    } catch (Exception e) {
                        container.getLogger().warn(sm.getString("cometConnectionManagerValve.event"), e);
                    }
                }
            }
        }
        connections.clear();

    }

    
    public void lifecycleEvent(LifecycleEvent event) {
        if (event.getType() == Lifecycle.BEFORE_STOP_EVENT) {
            // The webapp is getting stopped, so all current connections 
            // should be closed
            // Close all Comet connections associated with this session
            Iterator<ConnectionInfo[]> iterator = connections.values().iterator();
            while (iterator.hasNext()) {
                ConnectionInfo[] connectionInfos = iterator.next();
                if (connectionInfos != null) {
                    for (int i = 0; i < connectionInfos.length; i++) {
                        ConnectionInfo connectionInfo = connectionInfos[i];
                        try {
                            ((CometEventImpl) connectionInfo.event).setEventType(CometEvent.EventType.END);
                            ((CometEventImpl) connectionInfo.event).setEventSubType(CometEvent.EventSubType.WEBAPP_RELOAD);
                            getNext().event(connectionInfo.request, connectionInfo.response, connectionInfo.event);
                            connectionInfo.event.close();
                        } catch (Exception e) {
                            container.getLogger().warn(sm.getString("cometConnectionManagerValve.event"), e);
                        }
                    }
                }
            }
            connections.clear();
        }
    }


    // --------------------------------------------------------- Public Methods


    /**
     * Return descriptive information about this Valve implementation.
     */
    public String getInfo() {
        return (info);
    }


    /**
     * Register requests for tracking, whenever needed.
     *
     * @param request The servlet request to be processed
     * @param response The servlet response to be created
     *
     * @exception IOException if an input/output error occurs
     * @exception ServletException if a servlet error occurs
     */
    public void invoke(Request request, Response response)
        throws IOException, ServletException {
        // Perform the request
        getNext().invoke(request, response);
        
        if (request.isComet() && !response.isClosed()) {
            // Start tracking this connection, since this is a 
            // begin event, and Comet mode is on
            HttpSession session = request.getSession(true);
            ConnectionInfo newConnectionInfo = new ConnectionInfo();
            newConnectionInfo.request = request;
            newConnectionInfo.response = response;
            newConnectionInfo.event = request.getEvent();
            synchronized (session) {
                String id = session.getId();
                ConnectionInfo[] connectionInfos = connections.get(id);
                if (connectionInfos == null) {
                    connectionInfos = new ConnectionInfo[1];
                    connectionInfos[0] = newConnectionInfo;
                    connections.put(id, connectionInfos);
                } else {
                    ConnectionInfo[] newConnectionInfos = 
                        new ConnectionInfo[connectionInfos.length + 1];
                    for (int i = 0; i < connectionInfos.length; i++) {
                        newConnectionInfos[i] = connectionInfos[i];
                    }
                    newConnectionInfos[connectionInfos.length] = newConnectionInfo;
                    connections.put(id, newConnectionInfos);
                }
            }
        }
        
    }

    
    /**
     * Use events to update the connection state.
     *
     * @param request The servlet request to be processed
     * @param response The servlet response to be created
     *
     * @exception IOException if an input/output error occurs
     * @exception ServletException if a servlet error occurs
     */
    public void event(Request request, Response response, CometEvent event)
        throws IOException, ServletException {
        
        // Perform the request
        boolean ok = false;
        try {
            getNext().event(request, response, event);
            ok = true;
        } finally {
            if (!ok || response.isClosed() 
                    || (event.getEventType() == CometEvent.EventType.END)
                    || (event.getEventType() == CometEvent.EventType.ERROR
                            && !(event.getEventSubType() == CometEvent.EventSubType.TIMEOUT))) {
                // Remove from tracked list, the connection is done
                HttpSession session = request.getSession(true);
                synchronized (session) {
                    ConnectionInfo[] connectionInfos = connections.get(session.getId());
                    if (connectionInfos != null) {
                        boolean found = false;
                        for (int i = 0; !found && (i < connectionInfos.length); i++) {
                            found = (connectionInfos[i].request == request);
                        }
                        if (found) {
                            ConnectionInfo[] newConnectionInfos = 
                                new ConnectionInfo[connectionInfos.length - 1];
                            int pos = 0;
                            for (int i = 0; i < connectionInfos.length; i++) {
                                if (connectionInfos[i].request != request) {
                                    newConnectionInfos[pos++] = connectionInfos[i];
                                }
                            }
                            connections.put(session.getId(), newConnectionInfos);
                        }
                    }
                }                
            }
        }
        
    }


    public void sessionCreated(HttpSessionEvent se) {
    }


    public void sessionDestroyed(HttpSessionEvent se) {
        // Close all Comet connections associated with this session
        ConnectionInfo[] connectionInfos = connections.remove(se.getSession().getId());
        if (connectionInfos != null) {
            for (int i = 0; i < connectionInfos.length; i++) {
                ConnectionInfo connectionInfo = connectionInfos[i];
                try {
                    ((CometEventImpl) connectionInfo.event).setEventType(CometEvent.EventType.END);
                    ((CometEventImpl) connectionInfo.event).setEventSubType(CometEvent.EventSubType.SESSION_END);
                    getNext().event(connectionInfo.request, connectionInfo.response, connectionInfo.event);
                    connectionInfo.event.close();
                } catch (Exception e) {
                    container.getLogger().warn(sm.getString("cometConnectionManagerValve.event"), e);
                }
            }
        }
    }


    // --------------------------------------------- ConnectionInfo Inner Class

    
    protected class ConnectionInfo {
        public CometEvent event;
        public Request request;
        public Response response;
    }


}