1 /* 2 * Copyright (c) 2002, 2007, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package javax.management; 27 28 import java.util.concurrent.CopyOnWriteArrayList; // for Javadoc 29 30 /** 31 * <p>Interface implemented by an MBean that emits Notifications. It 32 * allows a listener to be registered with the MBean as a notification 33 * listener.</p> 34 * 35 * <h3>Notification dispatch</h3> 36 * 37 *<p>When an MBean emits a notification, it considers each listener that has been 38 * added with {@link #addNotificationListener addNotificationListener} and not 39 * subsequently removed with {@link #removeNotificationListener removeNotificationListener}. 40 * If a filter was provided with that listener, and if the filter's 41 * {@link NotificationFilter#isNotificationEnabled isNotificationEnabled} method returns 42 * false, the listener is ignored. Otherwise, the listener's 43 * {@link NotificationListener#handleNotification handleNotification} method is called with 44 * the notification, as well as the handback object that was provided to 45 * {@code addNotificationListener}.</p> 46 * 47 * <p>If the same listener is added more than once, it is considered as many times as it was 48 * added. It is often useful to add the same listener with different filters or handback 49 * objects.</p> 50 * 51 * <p>Implementations of this interface can differ regarding the thread in which the methods 52 * of filters and listeners are called.</p> 53 * 54 * <p>If the method call of a filter or listener throws an {@link Exception}, then that 55 * exception should not prevent other listeners from being invoked. However, if the method 56 * call throws an {@link Error}, then it is recommended that processing of the notification 57 * stop at that point, and if it is possible to propagate the {@code Error} to the sender of 58 * the notification, this should be done.</p> 59 * 60 * <p>This interface should be used by new code in preference to the 61 * {@link NotificationBroadcaster} interface.</p> 62 * 63 * <p>Implementations of this interface and of {@code NotificationBroadcaster} 64 * should be careful about synchronization. In particular, it is not a good 65 * idea for an implementation to hold any locks while it is calling a 66 * listener. To deal with the possibility that the list of listeners might 67 * change while a notification is being dispatched, a good strategy is to 68 * use a {@link CopyOnWriteArrayList} for this list. 69 * 70 * @since 1.5 71 */ 72 public interface NotificationEmitter extends NotificationBroadcaster { 73 /** 74 * <p>Removes a listener from this MBean. The MBean must have a 75 * listener that exactly matches the given <code>listener</code>, 76 * <code>filter</code>, and <code>handback</code> parameters. If 77 * there is more than one such listener, only one is removed.</p> 78 * 79 * <p>The <code>filter</code> and <code>handback</code> parameters 80 * may be null if and only if they are null in a listener to be 81 * removed.</p> 82 * 83 * @param listener A listener that was previously added to this 84 * MBean. 85 * @param filter The filter that was specified when the listener 86 * was added. 87 * @param handback The handback that was specified when the listener was 88 * added. 89 * 90 * @exception ListenerNotFoundException The listener is not 91 * registered with the MBean, or it is not registered with the 92 * given filter and handback. 93 */ removeNotificationListener(NotificationListener listener, NotificationFilter filter, Object handback)94 public void removeNotificationListener(NotificationListener listener, 95 NotificationFilter filter, 96 Object handback) 97 throws ListenerNotFoundException; 98 } 99