Glassfish example source code file (InstanceSupport.java)

This example Glassfish source code file (InstanceSupport.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 - Glassfish tags/keywords

filter, instanceevent, instanceevent, instancelistener, instancelistener, instancesupport, lock, servlet, servlet, servletrequest, servletrequest, servletresponse, throwable, wrapper

The Glassfish InstanceSupport.java source code

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright (c) 1997-2010 Oracle and/or its affiliates. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at packager/legal/LICENSE.txt.
 *
 * GPL Classpath Exception:
 * Oracle designates this particular file as subject to the "Classpath"
 * exception as provided by Oracle in the GPL Version 2 section of the License
 * file that accompanied this code.
 *
 * Modifications:
 * If applicable, add the following below the License Header, with the fields
 * enclosed by brackets [] replaced by your own identifying information:
 * "Portions Copyright [year] [name of copyright owner]"
 *
 * Contributor(s):
 * If you wish your version of this file to be governed by only the CDDL or
 * only the GPL Version 2, indicate your decision by adding "[Contributor]
 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
 * either the CDDL, the GPL Version 2 or to extend the choice of license to
 * its licensees as provided above.  However, if you add GPL Version 2 code
 * and therefore, elected the GPL Version 2 license, then the option applies
 * only if the new code is made subject to such option by the copyright
 * holder.
 *
 *
 * This file incorporates work covered by the following copyright and
 * permission notice:
 *
 * Copyright 2004 The Apache Software Foundation
 *
 * 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.apache.catalina.util;


import org.apache.catalina.InstanceEvent;
import org.apache.catalina.InstanceListener;
import org.apache.catalina.Wrapper;

import javax.servlet.Filter;
import javax.servlet.Servlet;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
// END SJSAS 6374619

/**
 * Support class to assist in firing InstanceEvent notifications to
 * registered InstanceListeners.
 *
 * @author Craig R. McClanahan
 * @version $Id: InstanceSupport.java,v 1.3 2006/03/09 20:38:05 jfarcand Exp $
 */

public final class InstanceSupport {


    // ----------------------------------------------------------- Constructors


    /**
     * Construct a new InstanceSupport object associated with the specified
     * Instance component.
     *
     * @param lifecycle The Instance component that will be the source
     *  of events that we fire
     */
    public InstanceSupport(Wrapper wrapper) {

        super();
        this.wrapper = wrapper;

    }


    // ----------------------------------------------------- Instance Variables
    // START SJSAS 6374619
    private ReadWriteLock listenersLock = new ReentrantReadWriteLock();
    private Lock listenersReadLock = listenersLock.readLock();
    private Lock listenersWriteLock = listenersLock.writeLock();
    // END SJSAS 6374619

    /**
     * The set of registered InstanceListeners for event notifications.
     */
    private InstanceListener listeners[] = new InstanceListener[0];


    /**
     * The source component for instance events that we will fire.
     */
    private Wrapper wrapper = null;


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


    /**
     * Return the Wrapper with which we are associated.
     */
    public Wrapper getWrapper() {

        return (this.wrapper);

    }


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


    /**
     * Add a lifecycle event listener to this component.
     *
     * @param listener The listener to add
     */
    public void addInstanceListener(InstanceListener listener) {
        /* SJSAS 6374619
        synchronized (listeners) {
          InstanceListener results[] =
            new InstanceListener[listeners.length + 1];
          for (int i = 0; i < listeners.length; i++)
              results[i] = listeners[i];
          results[listeners.length] = listener;
          listeners = results;
        }
        */
        // START SJSAS 6374619
        listenersWriteLock.lock();
        try {
            InstanceListener results[] =
                new InstanceListener[listeners.length + 1];
            for (int i = 0; i < listeners.length; i++)
              results[i] = listeners[i];
            results[listeners.length] = listener;
            listeners = results;
        } finally {
            listenersWriteLock.unlock();
        }
        // END SJSAS 6374619
    }


    /**
     * Notify all lifecycle event listeners that a particular event has
     * occurred for this Container.  The default implementation performs
     * this notification synchronously using the calling thread.
     *
     * @param type Event type
     * @param filter The relevant Filter for this event
     */
    public void fireInstanceEvent(InstanceEvent.EventType type, Filter filter) {

        if (listeners.length == 0)
            return;

        InstanceEvent event = new InstanceEvent(wrapper, filter, type);
        InstanceListener interested[] = null;
        /* SJSAS XXX
        synchronized (listeners) {
            interested = (InstanceListener[]) listeners.clone();
        }
        for (int i = 0; i < interested.length; i++)
            interested[i].instanceEvent(event);
        */
        // START SJSAS XXX
        listenersReadLock.lock();
        try {
            for (int i = 0; i < listeners.length; i++)
                listeners[i].instanceEvent(event);
        } finally {
            listenersReadLock.unlock();
        }
    }


    /**
     * Notify all lifecycle event listeners that a particular event has
     * occurred for this Container.  The default implementation performs
     * this notification synchronously using the calling thread.
     *
     * @param type Event type
     * @param filter The relevant Filter for this event
     * @param exception Exception that occurred
     */
    public void fireInstanceEvent(InstanceEvent.EventType type, Filter filter,
                                  Throwable exception) {

        if (listeners.length == 0)
            return;

        InstanceEvent event = new InstanceEvent(wrapper, filter, type,
                                                exception);
        /* SJSAS 6374619
        InstanceListener interested[] = null;
        synchronized (listeners) {
            interested = (InstanceListener[]) listeners.clone();
        }
        for (int i = 0; i < interested.length; i++)
            interested[i].instanceEvent(event);
        */
        // START SJSAS 6374619
        listenersReadLock.lock();
        try {
            for (int i = 0; i < listeners.length; i++)
                listeners[i].instanceEvent(event);
        } finally {
            listenersReadLock.unlock();
        }
        // END SJSAS 6374619

    }


    /**
     * Notify all lifecycle event listeners that a particular event has
     * occurred for this Container.  The default implementation performs
     * this notification synchronously using the calling thread.
     *
     * @param type Event type
     * @param filter The relevant Filter for this event
     * @param request The servlet request we are processing
     * @param response The servlet response we are processing
     */
    public void fireInstanceEvent(InstanceEvent.EventType type, Filter filter,
                                  ServletRequest request,
                                  ServletResponse response) {

        if (listeners.length == 0)
            return;

        InstanceEvent event = new InstanceEvent(wrapper, filter, type,
                                                request, response);
        /* SJSAS 6374619
        InstanceListener interested[] = null;
        synchronized (listeners) {
            interested = (InstanceListener[]) listeners.clone();
        }
        for (int i = 0; i < interested.length; i++)
            interested[i].instanceEvent(event);
        */
        // START SJSAS 6374619
        listenersReadLock.lock();
        try {
            for (int i = 0; i < listeners.length; i++)
                listeners[i].instanceEvent(event);
        } finally {
            listenersReadLock.unlock();
        }
        // END SJSAS 6374619
    }


    /**
     * Notify all lifecycle event listeners that a particular event has
     * occurred for this Container.  The default implementation performs
     * this notification synchronously using the calling thread.
     *
     * @param type Event type
     * @param filter The relevant Filter for this event
     * @param request The servlet request we are processing
     * @param response The servlet response we are processing
     * @param exception Exception that occurred
     */
    public void fireInstanceEvent(InstanceEvent.EventType type, Filter filter,
                                  ServletRequest request,
                                  ServletResponse response,
                                  Throwable exception) {

        if (listeners.length == 0)
            return;

        InstanceEvent event = new InstanceEvent(wrapper, filter, type,
                                                request, response, exception);
        /* SJSAS 6374619        
        InstanceListener interested[] = null;
        synchronized (listeners) {
            interested = (InstanceListener[]) listeners.clone();
        }
        for (int i = 0; i < interested.length; i++)
            interested[i].instanceEvent(event);
        */
        // START SJSAS 6374619
        listenersReadLock.lock();
        try {
            for (int i = 0; i < listeners.length; i++)
                listeners[i].instanceEvent(event);
        } finally {
            listenersReadLock.unlock();
        }
        // END SJSAS 6374619
    }


    /**
     * Notify all lifecycle event listeners that a particular event has
     * occurred for this Container.  The default implementation performs
     * this notification synchronously using the calling thread.
     *
     * @param type Event type
     * @param servlet The relevant Servlet for this event
     */
    public void fireInstanceEvent(InstanceEvent.EventType type, Servlet servlet) {

        if (listeners.length == 0)
            return;

        InstanceEvent event = new InstanceEvent(wrapper, servlet, type);
        /* SJSAS 6374619
        InstanceListener interested[] = null;
        synchronized (listeners) {
            interested = (InstanceListener[]) listeners.clone();
        }
        for (int i = 0; i < interested.length; i++)
            interested[i].instanceEvent(event);
        */
        // START SJSAS 6374619
        listenersReadLock.lock();
        try {
            for (int i = 0; i < listeners.length; i++)
                listeners[i].instanceEvent(event);
        } finally {
            listenersReadLock.unlock();
        }
        // END SJSAS 6374619
    }


    /**
     * Notify all lifecycle event listeners that a particular event has
     * occurred for this Container.  The default implementation performs
     * this notification synchronously using the calling thread.
     *
     * @param type Event type
     * @param servlet The relevant Servlet for this event
     * @param exception Exception that occurred
     */
    public void fireInstanceEvent(InstanceEvent.EventType type, Servlet servlet,
                                  Throwable exception) {

        if (listeners.length == 0)
            return;

        InstanceEvent event = new InstanceEvent(wrapper, servlet, type,
                                                exception);
        /* SJSAS 6374619
        InstanceListener interested[] = null;
        synchronized (listeners) {
            interested = (InstanceListener[]) listeners.clone();
        }
        for (int i = 0; i < interested.length; i++)
            interested[i].instanceEvent(event);
        */
        // START SJSAS 6374619
        listenersReadLock.lock();
        try {
            for (int i = 0; i < listeners.length; i++)
                listeners[i].instanceEvent(event);
        } finally {
            listenersReadLock.unlock();
        }
        // END SJSAS 6374619
    }


    /**
     * Notify all lifecycle event listeners that a particular event has
     * occurred for this Container.  The default implementation performs
     * this notification synchronously using the calling thread.
     *
     * @param type Event type
     * @param servlet The relevant Servlet for this event
     * @param request The servlet request we are processing
     * @param response The servlet response we are processing
     */
    public void fireInstanceEvent(InstanceEvent.EventType type, Servlet servlet,
                                  ServletRequest request,
                                  ServletResponse response) {

        if (listeners.length == 0)
            return;

        InstanceEvent event = new InstanceEvent(wrapper, servlet, type,
                                                request, response);
        /* SJSAS 6374619
        InstanceListener interested[] = null;
        synchronized (listeners) {
            interested = (InstanceListener[]) listeners.clone();
        }
        for (int i = 0; i < interested.length; i++)
            interested[i].instanceEvent(event);
        */
        // START SJSAS 6374619
        listenersReadLock.lock();
        try {
            for (int i = 0; i < listeners.length; i++)
                listeners[i].instanceEvent(event);
        } finally {
            listenersReadLock.unlock();
        }
        // END SJSAS 6374619
    }


    /**
     * Notify all lifecycle event listeners that a particular event has
     * occurred for this Container.  The default implementation performs
     * this notification synchronously using the calling thread.
     *
     * @param type Event type
     * @param servlet The relevant Servlet for this event
     * @param request The servlet request we are processing
     * @param response The servlet response we are processing
     * @param exception Exception that occurred
     */
    public void fireInstanceEvent(InstanceEvent.EventType type, Servlet servlet,
                                  ServletRequest request,
                                  ServletResponse response,
                                  Throwable exception) {

        if (listeners.length == 0)
            return;

        InstanceEvent event = new InstanceEvent(wrapper, servlet, type,
                                                request, response, exception);
        /* SJSAS 6374619
        InstanceListener interested[] = null;
        synchronized (listeners) {
            interested = (InstanceListener[]) listeners.clone();
        }
        for (int i = 0; i < interested.length; i++)
            interested[i].instanceEvent(event);
        */
        // START SJSAS 6374619
        listenersReadLock.lock();
        try {
            for (int i = 0; i < listeners.length; i++)
                listeners[i].instanceEvent(event);
        } finally {
            listenersReadLock.unlock();
        }
        // END SJSAS 6374619
    }


    /**
     * Remove a lifecycle event listener from this component.
     *
     * @param listener The listener to remove
     */
    public void removeInstanceListener(InstanceListener listener) {

        /* SJSAS 6374619
        synchronized (listeners) {
            int n = -1;
            for (int i = 0; i < listeners.length; i++) {
                if (listeners[i] == listener) {
                    n = i;
                    break;
                }
            }
            if (n < 0)
                return;
            InstanceListener results[] =
              new InstanceListener[listeners.length - 1];
            int j = 0;
            for (int i = 0; i < listeners.length; i++) {
                if (i != n)
                    results[j++] = listeners[i];
            }
            listeners = results;
        }
        */
        // START SJSAS 6374619
        listenersWriteLock.lock();
        try {
            int n = -1;
            for (int i = 0; i < listeners.length; i++) {
                if (listeners[i] == listener) {
                    n = i;
                    break;
                }
            }
            if (n < 0)
                return;
            InstanceListener results[] =
              new InstanceListener[listeners.length - 1];
            int j = 0;
            for (int i = 0; i < listeners.length; i++) {
                if (i != n)
                    results[j++] = listeners[i];
            }
            listeners = results;
        } finally {
            listenersWriteLock.unlock();
        }
        // END SJSAS 6374619
    }


}