Java example source code file (DiagnosticCommandMBean.java)

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Java - Java tags/keywords

diagnosticcommandmbean, dynamicmbean, management

The DiagnosticCommandMBean.java Java example source code

/*
 * Copyright (c) 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 com.sun.management;

import java.lang.management.PlatformManagedObject;
import javax.management.DynamicMBean;

/**
 * Management interface for the diagnostic commands for the HotSpot Virtual Machine.
 *
 * <p>The {code DiagnosticCommandMBean} is registered to the
 * {@linkplain java.lang.management.ManagementFactory#getPlatformMBeanServer
 * platform MBeanServer} as are other platform MBeans.
 *
 * <p>The {@link javax.management.ObjectName ObjectName} for uniquely identifying
 * the diagnostic MBean within an MBeanServer is:
 * <blockquote>
 *    {@code com.sun.management:type=DiagnosticCommand}
 * </blockquote>
 *
 * <p>This MBean is a {@link javax.management.DynamicMBean DynamicMBean}
 * and also a {@link javax.management.NotificationEmitter}.
 * The {@code DiagnosticCommandMBean} is generated at runtime and is subject to
 * modifications during the lifetime of the Java virtual machine.
 *
 * A <em>diagnostic command is represented as an operation of
 * the {@code DiagnosticCommandMBean} interface. Each diagnostic command has:
 * <ul>
 * <li>the diagnostic command name which is the name being referenced in
 *     the HotSpot Virtual Machine</li>
 * <li>the MBean operation name which is the
 *     {@linkplain javax.management.MBeanOperationInfo#getName() name}
 *     generated for the diagnostic command operation invocation.
 *     The MBean operation name is implementation dependent</li>
 * </ul>
 *
 * The recommended way to transform a diagnostic command name into a MBean
 * operation name is as follows:
 * <ul>
 * <li>All characters from the first one to the first dot are set to be
 *      lower-case characters</li>
 * <li>Every dot or underline character is removed and the following
 *   character is set to be an upper-case character</li>
 * <li>All other characters are copied without modification
 * </ul>
 *
 * <p>The diagnostic command name is always provided with the meta-data on the
 * operation in a field named {@code dcmd.name} (see below).
 *
 * <p>A diagnostic command may or may not support options or arguments.
 * All the operations return {@code String} and either take
 * no parameter for operations that do not support any option or argument,
 * or take a {@code String[]} parameter for operations that support at least
 * one option or argument.
 * Each option or argument must be stored in a single String.
 * Options or arguments split across several String instances are not supported.
 *
 * <p>The distinction between options and arguments: options are identified by
 * the option name while arguments are identified by their position in the
 * command line. Options and arguments are processed in the order of the array
 * passed to the invocation method.
 *
 * <p>Like any operation of a dynamic MBean, each of these operations is
 * described by {@link javax.management.MBeanOperationInfo MBeanOperationInfo}
 * instance. Here's the values returned by this object:
 * <ul>
 *  <li>{@link javax.management.MBeanOperationInfo#getName() getName()}
 *      returns the operation name generated from the diagnostic command name</li>
 *  <li>{@link javax.management.MBeanOperationInfo#getDescription() getDescription()}
 *      returns the diagnostic command description
 *      (the same as the one return in the 'help' command)</li>
 *  <li>{@link javax.management.MBeanOperationInfo#getImpact() getImpact()}
 *      returns <code>ACTION_INFO
 *  <li>{@link javax.management.MBeanOperationInfo#getReturnType() getReturnType()}
 *      returns {@code java.lang.String}</li>
 *  <li>{@link javax.management.MBeanOperationInfo#getDescriptor() getDescriptor()}
 *      returns a Descriptor instance (see below)</li>
 * </ul>
 *
 * <p>The {@link javax.management.Descriptor Descriptor}
 * is a collection of fields containing additional
 * meta-data for a JMX element. A field is a name and an associated value.
 * The additional meta-data provided for an operation associated with a
 * diagnostic command are described in the table below:
 * <p>
 *
 * <table border="1" cellpadding="5">
 *   <tr>
 *     <th>Name