1. /*

  2.  * $Header: /home/cvspublic/jakarta-commons/modeler/src/java/org/apache/commons/modeler/BaseNotificationBroadcaster.java,v 1.5 2003/07/20 07:35:13 ggregory Exp $

  3.  * $Revision: 1.5 $

  4.  * $Date: 2003/07/20 07:35:13 $

  5.  *

  6.  * ====================================================================

  7.  *

  8.  * The Apache Software License, Version 1.1

  9.  *

  10.  * Copyright (c) 1999 The Apache Software Foundation.  All rights

  11.  * reserved.

  12.  *

  13.  * Redistribution and use in source and binary forms, with or without

  14.  * modification, are permitted provided that the following conditions

  15.  * are met:

  16.  *

  17.  * 1. Redistributions of source code must retain the above copyright

  18.  *    notice, this list of conditions and the following disclaimer.

  19.  *

  20.  * 2. Redistributions in binary form must reproduce the above copyright

  21.  *    notice, this list of conditions and the following disclaimer in

  22.  *    the documentation and/or other materials provided with the

  23.  *    distribution.

  24.  *

  25.  * 3. The end-user documentation included with the redistribution, if

  26.  *    any, must include the following acknowlegement:

  27.  *       "This product includes software developed by the

  28.  *        Apache Software Foundation (http://www.apache.org/)."

  29.  *    Alternately, this acknowlegement may appear in the software itself,

  30.  *    if and wherever such third-party acknowlegements normally appear.

  31.  *

  32.  * 4. The names "The Jakarta Project", "Commons", and "Apache Software

  33.  *    Foundation" must not be used to endorse or promote products derived

  34.  *    from this software without prior written permission. For written

  35.  *    permission, please contact apache@apache.org.

  36.  *

  37.  * 5. Products derived from this software may not be called "Apache"

  38.  *    nor may "Apache" appear in their names without prior written

  39.  *    permission of the Apache Group.

  40.  *

  41.  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED

  42.  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

  43.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

  44.  * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR

  45.  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

  46.  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

  47.  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF

  48.  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND

  49.  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,

  50.  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT

  51.  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

  52.  * SUCH DAMAGE.

  53.  * ====================================================================

  54.  *

  55.  * This software consists of voluntary contributions made by many

  56.  * individuals on behalf of the Apache Software Foundation.  For more

  57.  * information on the Apache Software Foundation, please see

  58.  * <http://www.apache.org/>.

  59.  *

  60.  * [Additional notices, if required by prior licensing conditions]

  61.  *

  62.  */

  63. 

  64. 

  65. package org.apache.commons.modeler;

  66. 

  67. 

  68. import java.util.ArrayList;

  69. import java.util.Iterator;

  70. 

  71. import javax.management.ListenerNotFoundException;

  72. import javax.management.MBeanNotificationInfo;

  73. import javax.management.Notification;

  74. import javax.management.NotificationBroadcaster;

  75. import javax.management.NotificationFilter;

  76. import javax.management.NotificationListener;

  77. 

  78. 

  79. /**

  80.  * <p>Implementation of <code>NotificationBroadcaster</code> for attribute

  81.  * change notifications.  This class is used by <code>BaseModelMBean</code> to

  82.  * handle notifications of attribute change events to interested listeners.

  83.  *</p>

  84.  *

  85.  * @author Craig R. McClanahan

  86.  * @author Costin Manolache

  87.  */

  88. 

  89. public class BaseNotificationBroadcaster implements NotificationBroadcaster {

  90. 

  91. 

  92.     // ----------------------------------------------------------- Constructors

  93. 

  94. 

  95.     // ----------------------------------------------------- Instance Variables

  96. 

  97. 

  98.     /**

  99.      * The set of registered <code>BaseNotificationBroadcasterEntry</code>

  100.      * entries.

  101.      */

  102.     protected ArrayList entries = new ArrayList();

  103. 

  104. 

  105.     // --------------------------------------------------------- Public Methods

  106. 

  107. 

  108.     /**

  109.      * Add a notification event listener to this MBean.

  110.      *

  111.      * @param listener Listener that will receive event notifications

  112.      * @param filter Filter object used to filter event notifications

  113.      *  actually delivered, or <code>null</code> for no filtering

  114.      * @param handback Handback object to be sent along with event

  115.      *  notifications

  116.      *

  117.      * @exception IllegalArgumentException if the listener parameter is null

  118.      */

  119.     public void addNotificationListener(NotificationListener listener,

  120.                                         NotificationFilter filter,

  121.                                         Object handback)

  122.         throws IllegalArgumentException {

  123. 

  124.         synchronized (entries) {

  125. 

  126.             // Optimization to coalesce attribute name filters

  127.             if (filter instanceof BaseAttributeFilter) {

  128.                 BaseAttributeFilter newFilter = (BaseAttributeFilter) filter;

  129.                 Iterator items = entries.iterator();

  130.                 while (items.hasNext()) {

  131.                     BaseNotificationBroadcasterEntry item =

  132.                         (BaseNotificationBroadcasterEntry) items.next();

  133.                     if ((item.listener == listener) &&

  134.                         (item.filter != null) &&

  135.                         (item.filter instanceof BaseAttributeFilter) &&

  136.                         (item.handback == handback)) {

  137.                         BaseAttributeFilter oldFilter =

  138.                             (BaseAttributeFilter) item.filter;

  139.                         String newNames[] = newFilter.getNames();

  140.                         String oldNames[] = oldFilter.getNames();

  141.                         if (newNames.length == 0) {

  142.                             oldFilter.clear();

  143.                         } else {

  144.                             if (oldNames.length != 0) {

  145.                                 for (int i = 0; i < newNames.length; i++)

  146.                                     oldFilter.addAttribute(newNames[i]);

  147.                             }

  148.                         }

  149.                         return;

  150.                     }

  151.                 }

  152.             }

  153. 

  154.             // General purpose addition of a new entry

  155.             entries.add(new BaseNotificationBroadcasterEntry

  156.                         (listener, filter, handback));

  157.         }

  158. 

  159.     }

  160. 

  161. 

  162.     /**

  163.      * Return an <code>MBeanNotificationInfo</code> object describing the

  164.      * notifications sent by this MBean.

  165.      */

  166.     public MBeanNotificationInfo[] getNotificationInfo() {

  167. 

  168.         return (new MBeanNotificationInfo[0]);

  169. 

  170.     }

  171. 

  172. 

  173.     /**

  174.      * Remove a notification event listener from this MBean.

  175.      *

  176.      * @param listener The listener to be removed (any and all registrations

  177.      *  for this listener will be eliminated)

  178.      *

  179.      * @exception ListenerNotFoundException if this listener is not

  180.      *  registered in the MBean

  181.      */

  182.     public void removeNotificationListener(NotificationListener listener)

  183.         throws ListenerNotFoundException {

  184. 

  185.         synchronized (entries) {

  186.             Iterator items = entries.iterator();

  187.             while (items.hasNext()) {

  188.                 BaseNotificationBroadcasterEntry item =

  189.                     (BaseNotificationBroadcasterEntry) items.next();

  190.                 if (item.listener == listener)

  191.                     items.remove();

  192.             }

  193.         }

  194. 

  195.     }

  196. 

  197. 

  198.     /**

  199.      * Remove a notification event listener from this MBean.

  200.      *

  201.      * @param listener The listener to be removed (any and all registrations

  202.      *  for this listener will be eliminated)

  203.      * @param handback Handback object to be sent along with event

  204.      *  notifications

  205.      *

  206.      * @exception ListenerNotFoundException if this listener is not

  207.      *  registered in the MBean

  208.      */

  209.     public void removeNotificationListener(NotificationListener listener,

  210.                                            Object handback)

  211.         throws ListenerNotFoundException {

  212. 

  213.         removeNotificationListener(listener);

  214. 

  215.     }

  216. 

  217. 

  218.     /**

  219.      * Remove a notification event listener from this MBean.

  220.      *

  221.      * @param listener The listener to be removed (any and all registrations

  222.      *  for this listener will be eliminated)

  223.      * @param filter Filter object used to filter event notifications

  224.      *  actually delivered, or <code>null</code> for no filtering

  225.      * @param handback Handback object to be sent along with event

  226.      *  notifications

  227.      *

  228.      * @exception ListenerNotFoundException if this listener is not

  229.      *  registered in the MBean

  230.      */

  231.     public void removeNotificationListener(NotificationListener listener,

  232.                                            NotificationFilter filter,

  233.                                            Object handback)

  234.         throws ListenerNotFoundException {

  235. 

  236.         removeNotificationListener(listener);

  237. 

  238.     }

  239. 

  240. 

  241.     /**

  242.      * Send the specified notification to all interested listeners.

  243.      *

  244.      * @param notification The notification to be sent

  245.      */

  246.     public void sendNotification(Notification notification) {

  247. 

  248.         synchronized (entries) {

  249.             Iterator items = entries.iterator();

  250.             while (items.hasNext()) {

  251.                 BaseNotificationBroadcasterEntry item =

  252.                     (BaseNotificationBroadcasterEntry) items.next();

  253.                 if ((item.filter != null) &&

  254.                     (!item.filter.isNotificationEnabled(notification)))

  255.                     continue;

  256.                 item.listener.handleNotification(notification, item.handback);

  257.             }

  258.         }

  259. 

  260.     }

  261. 

  262. 

  263.     // -------------------- Internal Extensions   --------------------

  264. 

  265.     // Fast access. First index is the hook type

  266.     // ( FixedNotificationFilter.getType() ).

  267.     NotificationListener hooks[][]=new NotificationListener[20][];

  268.     int hookCount[]=new int[20];

  269. 

  270.     private synchronized void registerNotifications( FixedNotificationFilter filter ) {

  271.         String names[]=filter.getNames();

  272.         Registry reg=Registry.getRegistry();

  273.         for( int i=0; i<names.length; i++ ) {

  274.             int code=reg.getId(null, names[i]);

  275.             if( hooks.length < code ) {

  276.                 // XXX reallocate

  277.                 throw new RuntimeException( "Too many hooks " + code );

  278.             }

  279.             NotificationListener listeners[]=hooks[code];

  280.             if( listeners== null ) {

  281. 

  282.             }

  283. 

  284. 

  285.         }

  286.     }

  287. 

  288. }

  289. 

  290. 

  291. /**

  292.  * Utility class representing a particular registered listener entry.

  293.  */

  294. 

  295. class BaseNotificationBroadcasterEntry {

  296. 

  297.     public BaseNotificationBroadcasterEntry(NotificationListener listener,

  298.                                             NotificationFilter filter,

  299.                                             Object handback) {

  300.         this.listener = listener;

  301.         this.filter = filter;

  302.         this.handback = handback;

  303.     }

  304. 

  305.     public NotificationFilter filter = null;

  306. 

  307.     public Object handback = null;

  308. 

  309.     public NotificationListener listener = null;

  310. 

  311. }