Java tutorial
/* * Copyright (c) 2005, 2015, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package javax.management; /** * <p>An MBean whose management interface is determined by reflection * on a Java interface, and that emits notifications.</p> * * <p>The following example shows how to use the public constructor * {@link #StandardEmitterMBean(Object, Class, NotificationEmitter) * StandardEmitterMBean(implementation, mbeanInterface, emitter)} to * create an MBean emitting notifications with any * implementation class name <i>Impl</i>, with a management * interface defined (as for current Standard MBeans) by any interface * <i>Intf</i>, and with any implementation of the interface * {@link NotificationEmitter}. The example uses the class * {@link NotificationBroadcasterSupport} as an implementation * of the interface {@link NotificationEmitter}.</p> * * <pre> * MBeanServer mbs; * ... * final String[] types = new String[] {"sun.disc.space","sun.disc.alarm"}; * final MBeanNotificationInfo info = new MBeanNotificationInfo( * types, * Notification.class.getName(), * "Notification about disc info."); * final NotificationEmitter emitter = * new NotificationBroadcasterSupport(info); * * final Intf impl = new Impl(...); * final Object mbean = new StandardEmitterMBean( * impl, Intf.class, emitter); * mbs.registerMBean(mbean, objectName); * </pre> * * @see StandardMBean * * @since 1.6 */ public class StandardEmitterMBean extends StandardMBean implements NotificationEmitter { private static final MBeanNotificationInfo[] NO_NOTIFICATION_INFO = new MBeanNotificationInfo[0]; private final NotificationEmitter emitter; private final MBeanNotificationInfo[] notificationInfo; /** * <p>Make an MBean whose management interface is specified by * {@code mbeanInterface}, with the given implementation and * where notifications are handled by the given {@code NotificationEmitter}. * The resultant MBean implements the {@code NotificationEmitter} interface * by forwarding its methods to {@code emitter}. It is legal and useful * for {@code implementation} and {@code emitter} to be the same object.</p> * * <p>If {@code emitter} is an instance of {@code * NotificationBroadcasterSupport} then the MBean's {@link #sendNotification * sendNotification} method will call {@code emitter.}{@link * NotificationBroadcasterSupport#sendNotification sendNotification}.</p> * * <p>The array returned by {@link #getNotificationInfo()} on the * new MBean is a copy of the array returned by * {@code emitter.}{@link NotificationBroadcaster#getNotificationInfo * getNotificationInfo()} at the time of construction. If the array * returned by {@code emitter.getNotificationInfo()} later changes, * that will have no effect on this object's * {@code getNotificationInfo()}.</p> * * @param <T> the implementation type of the MBean * @param implementation the implementation of the MBean interface. * @param mbeanInterface a Standard MBean interface. * @param emitter the object that will handle notifications. * * @throws IllegalArgumentException if the {@code mbeanInterface} * does not follow JMX design patterns for Management Interfaces, or * if the given {@code implementation} does not implement the * specified interface, or if {@code emitter} is null. */ public <T> StandardEmitterMBean(T implementation, Class<T> mbeanInterface, NotificationEmitter emitter) { this(implementation, mbeanInterface, false, emitter); } /** * <p>Make an MBean whose management interface is specified by * {@code mbeanInterface}, with the given implementation and where * notifications are handled by the given {@code * NotificationEmitter}. This constructor can be used to make * either Standard MBeans or MXBeans. The resultant MBean * implements the {@code NotificationEmitter} interface by * forwarding its methods to {@code emitter}. It is legal and * useful for {@code implementation} and {@code emitter} to be the * same object.</p> * * <p>If {@code emitter} is an instance of {@code * NotificationBroadcasterSupport} then the MBean's {@link #sendNotification * sendNotification} method will call {@code emitter.}{@link * NotificationBroadcasterSupport#sendNotification sendNotification}.</p> * * <p>The array returned by {@link #getNotificationInfo()} on the * new MBean is a copy of the array returned by * {@code emitter.}{@link NotificationBroadcaster#getNotificationInfo * getNotificationInfo()} at the time of construction. If the array * returned by {@code emitter.getNotificationInfo()} later changes, * that will have no effect on this object's * {@code getNotificationInfo()}.</p> * * @param <T> the implementation type of the MBean * @param implementation the implementation of the MBean interface. * @param mbeanInterface a Standard MBean interface. * @param isMXBean If true, the {@code mbeanInterface} parameter * names an MXBean interface and the resultant MBean is an MXBean. * @param emitter the object that will handle notifications. * * @throws IllegalArgumentException if the {@code mbeanInterface} * does not follow JMX design patterns for Management Interfaces, or * if the given {@code implementation} does not implement the * specified interface, or if {@code emitter} is null. */ public <T> StandardEmitterMBean(T implementation, Class<T> mbeanInterface, boolean isMXBean, NotificationEmitter emitter) { super(implementation, mbeanInterface, isMXBean); if (emitter == null) throw new IllegalArgumentException("Null emitter"); this.emitter = emitter; MBeanNotificationInfo[] infos = emitter.getNotificationInfo(); if (infos == null || infos.length == 0) { this.notificationInfo = NO_NOTIFICATION_INFO; } else { this.notificationInfo = infos.clone(); } } /** * <p>Make an MBean whose management interface is specified by * {@code mbeanInterface}, and * where notifications are handled by the given {@code NotificationEmitter}. * The resultant MBean implements the {@code NotificationEmitter} interface * by forwarding its methods to {@code emitter}.</p> * * <p>If {@code emitter} is an instance of {@code * NotificationBroadcasterSupport} then the MBean's {@link #sendNotification * sendNotification} method will call {@code emitter.}{@link * NotificationBroadcasterSupport#sendNotification sendNotification}.</p> * * <p>The array returned by {@link #getNotificationInfo()} on the * new MBean is a copy of the array returned by * {@code emitter.}{@link NotificationBroadcaster#getNotificationInfo * getNotificationInfo()} at the time of construction. If the array * returned by {@code emitter.getNotificationInfo()} later changes, * that will have no effect on this object's * {@code getNotificationInfo()}.</p> * * <p>This constructor must be called from a subclass that implements * the given {@code mbeanInterface}.</p> * * @param mbeanInterface a StandardMBean interface. * @param emitter the object that will handle notifications. * * @throws IllegalArgumentException if the {@code mbeanInterface} * does not follow JMX design patterns for Management Interfaces, or * if {@code this} does not implement the specified interface, or * if {@code emitter} is null. */ protected StandardEmitterMBean(Class<?> mbeanInterface, NotificationEmitter emitter) { this(mbeanInterface, false, emitter); } /** * <p>Make an MBean whose management interface is specified by * {@code mbeanInterface}, and where notifications are handled by * the given {@code NotificationEmitter}. This constructor can be * used to make either Standard MBeans or MXBeans. The resultant * MBean implements the {@code NotificationEmitter} interface by * forwarding its methods to {@code emitter}.</p> * * <p>If {@code emitter} is an instance of {@code * NotificationBroadcasterSupport} then the MBean's {@link #sendNotification * sendNotification} method will call {@code emitter.}{@link * NotificationBroadcasterSupport#sendNotification sendNotification}.</p> * * <p>The array returned by {@link #getNotificationInfo()} on the * new MBean is a copy of the array returned by * {@code emitter.}{@link NotificationBroadcaster#getNotificationInfo * getNotificationInfo()} at the time of construction. If the array * returned by {@code emitter.getNotificationInfo()} later changes, * that will have no effect on this object's * {@code getNotificationInfo()}.</p> * * <p>This constructor must be called from a subclass that implements * the given {@code mbeanInterface}.</p> * * @param mbeanInterface a StandardMBean interface. * @param isMXBean If true, the {@code mbeanInterface} parameter * names an MXBean interface and the resultant MBean is an MXBean. * @param emitter the object that will handle notifications. * * @throws IllegalArgumentException if the {@code mbeanInterface} * does not follow JMX design patterns for Management Interfaces, or * if {@code this} does not implement the specified interface, or * if {@code emitter} is null. */ protected StandardEmitterMBean(Class<?> mbeanInterface, boolean isMXBean, NotificationEmitter emitter) { super(mbeanInterface, isMXBean); if (emitter == null) throw new IllegalArgumentException("Null emitter"); this.emitter = emitter; MBeanNotificationInfo[] infos = emitter.getNotificationInfo(); if (infos == null || infos.length == 0) { this.notificationInfo = NO_NOTIFICATION_INFO; } else { this.notificationInfo = infos.clone(); } } public void removeNotificationListener(NotificationListener listener) throws ListenerNotFoundException { emitter.removeNotificationListener(listener); } public void removeNotificationListener(NotificationListener listener, NotificationFilter filter, Object handback) throws ListenerNotFoundException { emitter.removeNotificationListener(listener, filter, handback); } public void addNotificationListener(NotificationListener listener, NotificationFilter filter, Object handback) { emitter.addNotificationListener(listener, filter, handback); } public MBeanNotificationInfo[] getNotificationInfo() { // this getter might get called from the super constructor // when the notificationInfo has not been properly set yet if (notificationInfo == null) { return NO_NOTIFICATION_INFO; } if (notificationInfo.length == 0) { return notificationInfo; } else { return notificationInfo.clone(); } } /** * <p>Sends a notification.</p> * * <p>If the {@code emitter} parameter to the constructor was an * instance of {@code NotificationBroadcasterSupport} then this * method will call {@code emitter.}{@link * NotificationBroadcasterSupport#sendNotification * sendNotification}.</p> * * @param n the notification to send. * * @throws ClassCastException if the {@code emitter} parameter to the * constructor was not a {@code NotificationBroadcasterSupport}. */ public void sendNotification(Notification n) { if (emitter instanceof NotificationBroadcasterSupport) ((NotificationBroadcasterSupport) emitter).sendNotification(n); else { final String msg = "Cannot sendNotification when emitter is not an " + "instance of NotificationBroadcasterSupport: " + emitter.getClass().getName(); throw new ClassCastException(msg); } } /** * <p>Get the MBeanNotificationInfo[] that will be used in the * MBeanInfo returned by this MBean.</p> * * <p>The default implementation of this method returns * {@link #getNotificationInfo()}.</p> * * @param info The default MBeanInfo derived by reflection. * @return the MBeanNotificationInfo[] for the new MBeanInfo. */ @Override MBeanNotificationInfo[] getNotifications(MBeanInfo info) { return getNotificationInfo(); } }