J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1999-2005 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | |
| 27 | package javax.management; |
| 28 | |
| 29 | import java.util.concurrent.CopyOnWriteArrayList; // for Javadoc |
| 30 | |
| 31 | /** |
| 32 | * <p>Interface implemented by an MBean that emits Notifications. It |
| 33 | * allows a listener to be registered with the MBean as a notification |
| 34 | * listener.</p> |
| 35 | * |
| 36 | * <h3>Notification dispatch</h3> |
| 37 | * |
| 38 | * <p>When an MBean emits a notification, it considers each listener that has been |
| 39 | * added with {@link #addNotificationListener addNotificationListener} and not |
| 40 | * subsequently removed with {@link #removeNotificationListener removeNotificationListener}. |
| 41 | * If a filter was provided with that listener, and if the filter's |
| 42 | * {@link NotificationFilter#isNotificationEnabled isNotificationEnabled} method returns |
| 43 | * false, the listener is ignored. Otherwise, the listener's |
| 44 | * {@link NotificationListener#handleNotification handleNotification} method is called with |
| 45 | * the notification, as well as the handback object that was provided to |
| 46 | * {@code addNotificationListener}.</p> |
| 47 | * |
| 48 | * <p>If the same listener is added more than once, it is considered as many times as it was |
| 49 | * added. It is often useful to add the same listener with different filters or handback |
| 50 | * objects.</p> |
| 51 | * |
| 52 | * <p>Implementations of this interface can differ regarding the thread in which the methods |
| 53 | * of filters and listeners are called.</p> |
| 54 | * |
| 55 | * <p>If the method call of a filter or listener throws an {@link Exception}, then that |
| 56 | * exception should not prevent other listeners from being invoked. However, if the method |
| 57 | * call throws an {@link Error}, then it is recommended that processing of the notification |
| 58 | * stop at that point, and if it is possible to propagate the {@code Error} to the sender of |
| 59 | * the notification, this should be done.</p> |
| 60 | * |
| 61 | * <p>New code should use the {@link NotificationEmitter} interface |
| 62 | * instead.</p> |
| 63 | * |
| 64 | * <p>Implementations of this interface and of {@code NotificationEmitter} |
| 65 | * should be careful about synchronization. In particular, it is not a good |
| 66 | * idea for an implementation to hold any locks while it is calling a |
| 67 | * listener. To deal with the possibility that the list of listeners might |
| 68 | * change while a notification is being dispatched, a good strategy is to |
| 69 | * use a {@link CopyOnWriteArrayList} for this list. |
| 70 | * |
| 71 | * @since 1.5 |
| 72 | */ |
| 73 | public interface NotificationBroadcaster { |
| 74 | |
| 75 | /** |
| 76 | * Adds a listener to this MBean. |
| 77 | * |
| 78 | * @param listener The listener object which will handle the |
| 79 | * notifications emitted by the broadcaster. |
| 80 | * @param filter The filter object. If filter is null, no |
| 81 | * filtering will be performed before handling notifications. |
| 82 | * @param handback An opaque object to be sent back to the |
| 83 | * listener when a notification is emitted. This object cannot be |
| 84 | * used by the Notification broadcaster object. It should be |
| 85 | * resent unchanged with the notification to the listener. |
| 86 | * |
| 87 | * @exception IllegalArgumentException Listener parameter is null. |
| 88 | * |
| 89 | * @see #removeNotificationListener |
| 90 | */ |
| 91 | public void addNotificationListener(NotificationListener listener, |
| 92 | NotificationFilter filter, |
| 93 | Object handback) |
| 94 | throws java.lang.IllegalArgumentException; |
| 95 | |
| 96 | /** |
| 97 | * Removes a listener from this MBean. If the listener |
| 98 | * has been registered with different handback objects or |
| 99 | * notification filters, all entries corresponding to the listener |
| 100 | * will be removed. |
| 101 | * |
| 102 | * @param listener A listener that was previously added to this |
| 103 | * MBean. |
| 104 | * |
| 105 | * @exception ListenerNotFoundException The listener is not |
| 106 | * registered with the MBean. |
| 107 | * |
| 108 | * @see #addNotificationListener |
| 109 | * @see NotificationEmitter#removeNotificationListener |
| 110 | */ |
| 111 | public void removeNotificationListener(NotificationListener listener) |
| 112 | throws ListenerNotFoundException; |
| 113 | |
| 114 | /** |
| 115 | * <p>Returns an array indicating, for each notification this |
| 116 | * MBean may send, the name of the Java class of the notification |
| 117 | * and the notification type.</p> |
| 118 | * |
| 119 | * <p>It is not illegal for the MBean to send notifications not |
| 120 | * described in this array. However, some clients of the MBean |
| 121 | * server may depend on the array being complete for their correct |
| 122 | * functioning.</p> |
| 123 | * |
| 124 | * @return the array of possible notifications. |
| 125 | */ |
| 126 | public MBeanNotificationInfo[] getNotificationInfo(); |
| 127 | } |