Java tutorial
/* * Copyright (c) 1999, 2013, 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; import java.io.IOException; import java.io.InvalidObjectException; import java.io.ObjectInputStream; import java.util.Arrays; import java.util.Objects; /** * <p>The {@code MBeanNotificationInfo} class is used to describe the * characteristics of the different notification instances * emitted by an MBean, for a given Java class of notification. * If an MBean emits notifications that can be instances of different Java classes, * then the metadata for that MBean should provide an {@code MBeanNotificationInfo} * object for each of these notification Java classes.</p> * * <p>Instances of this class are immutable. Subclasses may be * mutable but this is not recommended.</p> * * <p>This class extends {@code javax.management.MBeanFeatureInfo} * and thus provides {@code name} and {@code description} fields. * The {@code name} field should be the fully qualified Java class name of * the notification objects described by this class.</p> * * <p>The {@code getNotifTypes} method returns an array of * strings containing the notification types that the MBean may * emit. The notification type is a dot-notation string which * describes what the emitted notification is about, not the Java * class of the notification. A single generic notification class can * be used to send notifications of several types. All of these types * are returned in the string array result of the * {@code getNotifTypes} method. * * @since 1.5 */ public class MBeanNotificationInfo extends MBeanFeatureInfo implements Cloneable { /* Serial version */ static final long serialVersionUID = -3888371564530107064L; private static final String[] NO_TYPES = new String[0]; static final MBeanNotificationInfo[] NO_NOTIFICATIONS = new MBeanNotificationInfo[0]; /** * @serial The different types of the notification. */ private String[] types; /** @see MBeanInfo#arrayGettersSafe */ private final transient boolean arrayGettersSafe; /** * Constructs an {@code MBeanNotificationInfo} object. * * @param notifTypes The array of strings (in dot notation) * containing the notification types that the MBean may emit. * This may be null with the same effect as a zero-length array. * @param name The fully qualified Java class name of the * described notifications. * @param description A human readable description of the data. */ public MBeanNotificationInfo(String[] notifTypes, String name, String description) { this(notifTypes, name, description, null); } /** * Constructs an {@code MBeanNotificationInfo} object. * * @param notifTypes The array of strings (in dot notation) * containing the notification types that the MBean may emit. * This may be null with the same effect as a zero-length array. * @param name The fully qualified Java class name of the * described notifications. * @param description A human readable description of the data. * @param descriptor The descriptor for the notifications. This may be null * which is equivalent to an empty descriptor. * * @since 1.6 */ public MBeanNotificationInfo(String[] notifTypes, String name, String description, Descriptor descriptor) { super(name, description, descriptor); /* We do not validate the notifTypes, since the spec just says they are dot-separated, not that they must look like Java classes. E.g. the spec doesn't forbid "sun.prob.25" as a notifType, though it doesn't explicitly allow it either. */ this.types = (notifTypes != null && notifTypes.length > 0) ? notifTypes.clone() : NO_TYPES; this.arrayGettersSafe = MBeanInfo.arrayGettersSafe(this.getClass(), MBeanNotificationInfo.class); } /** * Returns a shallow clone of this instance. * The clone is obtained by simply calling {@code super.clone()}, * thus calling the default native shallow cloning mechanism * implemented by {@code Object.clone()}. * No deeper cloning of any internal field is made. */ public Object clone() { try { return super.clone(); } catch (CloneNotSupportedException e) { // should not happen as this class is cloneable return null; } } /** * Returns the array of strings (in dot notation) containing the * notification types that the MBean may emit. * * @return the array of strings. Changing the returned array has no * effect on this MBeanNotificationInfo. */ public String[] getNotifTypes() { if (types.length == 0) return NO_TYPES; else return types.clone(); } private String[] fastGetNotifTypes() { if (arrayGettersSafe) return types; else return getNotifTypes(); } public String toString() { return getClass().getName() + "[" + "description=" + getDescription() + ", " + "name=" + getName() + ", " + "notifTypes=" + Arrays.asList(fastGetNotifTypes()) + ", " + "descriptor=" + getDescriptor() + "]"; } /** * Compare this MBeanNotificationInfo to another. * * @param o the object to compare to. * * @return true if and only if {@code o} is an MBeanNotificationInfo * such that its {@link #getName()}, {@link #getDescription()}, * {@link #getDescriptor()}, * and {@link #getNotifTypes()} values are equal (not necessarily * identical) to those of this MBeanNotificationInfo. Two * notification type arrays are equal if their corresponding * elements are equal. They are not equal if they have the same * elements but in a different order. */ public boolean equals(Object o) { if (o == this) return true; if (!(o instanceof MBeanNotificationInfo)) return false; MBeanNotificationInfo p = (MBeanNotificationInfo) o; return (Objects.equals(p.getName(), getName()) && Objects.equals(p.getDescription(), getDescription()) && Objects.equals(p.getDescriptor(), getDescriptor()) && Arrays.equals(p.fastGetNotifTypes(), fastGetNotifTypes())); } public int hashCode() { int hash = getName().hashCode(); for (int i = 0; i < types.length; i++) hash ^= types[i].hashCode(); return hash; } private void readObject(ObjectInputStream ois) throws IOException, ClassNotFoundException { ObjectInputStream.GetField gf = ois.readFields(); String[] t = (String[]) gf.get("types", null); types = (t != null && t.length != 0) ? t.clone() : NO_TYPES; } }