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Glassfish example source code file (ServerNotificationManager.java)

This example Glassfish source code file (ServerNotificationManager.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

arraylist, arraylist, hashmap, interruptedexception, io, iterator, listenerinfo, listenerinfo, logging, notificationconnection, notificationconnection, object, objectname, request, response, servernotificationmanager, servlet, string, string, util

The Glassfish ServerNotificationManager.java source code

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright (c) 2006-2010 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.
 */

package com.sun.enterprise.admin.jmx.remote.server.notification;

import java.io.IOException;
import java.io.OutputStream;

import java.util.logging.Logger;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;

import javax.servlet.*;
import javax.servlet.http.*;

import javax.management.*;

import com.sun.enterprise.admin.jmx.remote.DefaultConfiguration;
import com.sun.enterprise.admin.jmx.remote.notification.NotificationWrapper;
import com.sun.enterprise.admin.jmx.remote.notification.ListenerInfo;


/**
 * This is the NotificationManager on the server-side responsible for
 * dipatching notifications to the clients.
 * The ServerNotificationManager maintains a list of NotificationConnection objects
 * for each client.
 */
public class ServerNotificationManager implements Runnable {
    private HashMap connections = null;
    private HashMap listenerMap = null;
    private boolean exiting = false;
    private Thread keepAliveThr = null;
    private MBeanServerConnection mbsc = null;
    private int bufsiz = DefaultConfiguration.NOTIF_MAX_BUFSIZ;

    private static final Logger logger = Logger.getLogger(
        DefaultConfiguration.JMXCONNECTOR_LOGGER);/*, 
        DefaultConfiguration.LOGGER_RESOURCE_BUNDLE_NAME );*/

    public ServerNotificationManager(MBeanServerConnection mbsc) {
        this.mbsc = mbsc;
        connections = new HashMap();
        listenerMap = new HashMap();
        keepAliveThr = new Thread(this);
        keepAliveThr.start();
    }

    /**
     * Initializes the notification buffer size for new NotificationConnection objects.
     * The buffer size can be set via the property com.sun.jmx.remote.http.notification.bufsize
     * The property can be set as an init-param for the server-side connector servlet.
     */
    public void setBufSiz(ServletConfig cfg) {
        String bsiz = cfg.getInitParameter(DefaultConfiguration.NOTIF_BUFSIZ_PROPERTY_NAME);
        if (bsiz == null || bsiz.trim().length() == 0)
            bsiz = System.getProperty("com.sun.web.jmx.connector.notification.bufsiz");
        try {
            bufsiz = Integer.parseInt(bsiz);
        } catch (NumberFormatException nume) {
            bufsiz = DefaultConfiguration.NOTIF_MAX_BUFSIZ;
        }
        if (bufsiz <= DefaultConfiguration.NOTIF_MIN_BUFSIZ)
            bufsiz = DefaultConfiguration.NOTIF_MAX_BUFSIZ;
    }

    private void closeConnection(String id, boolean unregisterNotifications) {
        NotificationConnection conn =
                    (NotificationConnection) connections.get(id);
        if (conn != null) {
            if (unregisterNotifications) {
                unregisterNotifications(id);
            }
            connections.remove(id);
            conn.close();
            synchronized (conn) {
                conn.notify();
            }
        }
    }

    private void unregisterNotifications(String id) {
        synchronized (listenerMap) {
            Iterator itr = listenerMap.keySet().iterator();
            while (itr.hasNext()) {
                ObjectName mbean = (ObjectName) itr.next();
                ArrayList list = (ArrayList) listenerMap.get(mbean);
                for (int i=0, len=list.size(); i < len; i++) {
                    ListenerInfo info = (ListenerInfo) list.get(i);
                    if (info.proxy != null &&
                        ((NotificationListenerProxy)info.proxy).getId() == id) {
                        list.remove(i);
                        try {
                            mbsc.removeNotificationListener(
                                mbean, ((NotificationListener)info.proxy));
                        } catch (Exception ex) {
                            // XXX: Log it
                        }
                    }
                }
                listenerMap.put(mbean, list);
            }
        }
    }

    /**
     * getNotifications() is called a client connects to the server or is sending a close message.
     * This method will create a new NotificationConnection object to represent the client.
     * This method will block until the connection needs to be closed or if the
     * connection drops.
     * In case the client is reconnecting (because the connection had dropped),
     * then a NotificationConnection object is created, only if a connection object
     * for the client is not already found.
     */
    public void getNotifications(HttpServletRequest req, HttpServletResponse res) {
        String id = req.getParameter(DefaultConfiguration.NOTIF_ID_PARAM);
        String cmd = req.getParameter(DefaultConfiguration.NOTIF_CMD_PARAM);
        res.setStatus(res.SC_OK);
        res.setHeader("Content-Type", "application/octet-stream");
        res.setHeader("Connection", "Keep-Alive");
        if (cmd != null && cmd.trim().equals(DefaultConfiguration.NOTIF_CMD_CLOSE)) {
            synchronized (connections) {
                closeConnection(id, true);
            }
            return;
        }
        NotificationConnection connection = null;
        try {
            OutputStream out = res.getOutputStream();
            synchronized (connections) {
                connection = (NotificationConnection) connections.get(id);
                if (connection == null) {
                    connection = new NotificationConnection(out, bufsiz);
                    connections.put(id, connection);
                } else {
                    connection.reinit(out);
                }
            }
            out.flush();
        } catch (IOException ioex) {
            // TODO: Log it
            try {
                res.sendError(res.SC_SERVICE_UNAVAILABLE, "Unable to send notifications, since OutputStream could not be opened");
            } catch (IOException ioe) {
                // TODO: Log it
            }
            return;
        }
        synchronized (connection) {
            while (!connection.hasIOExceptionOccurred()) {
                try {
                    connection.wait();
                    break; // somebody notified
                } catch (InterruptedException intre) {
                    // continue
                }
            }
        }
    }

    /**
     * Called whenever the webapp is being shutdown by the servlet container
     */
    public void close() {
        exiting = true;
        while (true) {
            try {
                keepAliveThr.join();
                break;
            } catch (InterruptedException intr) {
            }
        }
        NotificationConnection conn = null;
        synchronized (connections) {
            HashMap conns = (HashMap) connections.clone();
            Iterator itr = conns.keySet().iterator();
            while (itr.hasNext()) {
                String id = (String) itr.next();
                closeConnection(id, false);
            }
        }
    }

    public boolean isExiting() {
        return exiting;
    }

    /**
     * The keepalive thread that sends an empty notification to every client every 10 seconds.
     */
    public void run() {
        while (!isExiting()) {
            try {
                Thread.sleep(DefaultConfiguration.NOTIF_WAIT_INTERVAL);
            } catch (InterruptedException intrEx) {
                // Ignore any interrupts
            }
            if (isExiting())
                break;
            Iterator itr = getConnectionsIterator();
            NotificationConnection conn = null;
            synchronized (connections) {
                while (itr.hasNext() && !isExiting()) {
                    String id = (String) itr.next();
                    conn = (NotificationConnection) connections.get(id);
                    conn.fireWaitNotif();
                }
            }
        }
    }

    private Iterator getConnectionsIterator() {
        Iterator itr = null;
        synchronized (connections) {
            itr = connections.keySet().iterator();
        }
        return itr;
    }

    /**
     * fireNotification() is invoked by NotificationListenerProxy, whenever a notification
     * is sent by any NotificationBroadcaster.
     */
    public void fireNotification(NotificationListenerProxy proxy) {
        String id = proxy.getId();
        if (id == null || id.trim().length() == 0)
            return; // Drop this notification; Nobody is listening for this notification
        NotificationConnection conn = null;
        synchronized (connections) {
            conn = (NotificationConnection) connections.get(id);
        }
        if (conn == null)
            return; // Drop this notification; Nobody is listening for this notification

        conn.fireNotification(proxy.getNotificationWrapper());
    }

    private synchronized void addListenerInfo(ObjectName mbean,
                                              ListenerInfo info) {
        ArrayList list = (ArrayList) listenerMap.get(mbean);
        if (list == null)
            list = new ArrayList();
        list.add(info);
        listenerMap.put(mbean, list);
    }

    /**
     * Registers a notification listener for proper removal, for all registrations
     * done by a call to addNotificationListener(ObjectName, ObjectName, ...).
     * Since, the reference of the filter and handback objects is matched by
     * the NotificationBroadcaster, the ServerNotificationManager would register
     * the actual filter and handback object registered, with the NotificationBroadcaster,
     * and is bound to an id, refering this registration, sent by the client.
     */
    public String addObjNameNotificationListener(ObjectName mbean,
                                                 NotificationFilter filter,
                                                 Object handback,
                                                 String id) {
        ListenerInfo info = new ListenerInfo();
        info.filter = filter;
        info.handback = handback;
        info.id = id;
        addListenerInfo(mbean, info);
        return info.id;
   }

    /**
     * Registers a notification listener for proper removal, for all registrations
     * done by a call to addNotificationListener(ObjectName, NotificationListener, ...).
     * Since, the reference of the filter and handback objects is matched by
     * the NotificationBroadcaster, the ServerNotificationManager would register
     * the actual filter and handback object registered, with the NotificationBroadcaster,
     * and is bound to an id, refering this registration, sent by the client.
     */
    public String addNotificationListener(ObjectName mbean,
                                          String id,
                                          Object proxy) {
        ListenerInfo info = new ListenerInfo();
        info.id = id;
        info.proxy = proxy;
        addListenerInfo(mbean, info);

        return info.id;
    }

    private synchronized Object removeListenerInfo(
                ObjectName mbean, String id, boolean getProxy) {
        ArrayList list = (ArrayList) listenerMap.get(mbean);
        Iterator itr = null;
        if (list == null)
            return null;
        itr = list.iterator();
        while (itr.hasNext()) {
            ListenerInfo info = (ListenerInfo) itr.next();
            if (info.id.equals(id)) {
                list.remove(list.indexOf(info));
                Object retObj = null;
                if (getProxy)
                    retObj = info.proxy;
                else
                    retObj = info;
                return retObj;
            }
        }

        return null;
    }

    /**
     * Removes a registered NotificationListener, when
     * removeNotificationListener(ObjectName, ObjectName, ...) is called.
     */
    public ListenerInfo removeObjNameNotificationListener(ObjectName mbean,
                                                          String id) {
        return (ListenerInfo) removeListenerInfo(mbean, id, false);
    }

    /**
     * Removes a registered NotificationListener, when
     * removeNotificationListener(ObjectName, NotificationListener, ...) is called.
     */
    public Object removeNotificationListener(   ObjectName mbean,
                                                String id) {
        return removeListenerInfo(mbean, id, true);
    }
}

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