1 /*
2 * Copyright (c) 2013, 2018, 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 com.sun.management;
27
28 import java.lang.management.PlatformManagedObject;
29 import javax.management.DynamicMBean;
30
31 /**
32 * Management interface for the diagnostic commands for the HotSpot Virtual Machine.
33 *
34 * <p>The {@code DiagnosticCommandMBean} is registered to the
35 * {@linkplain java.lang.management.ManagementFactory#getPlatformMBeanServer
36 * platform MBeanServer} as are other platform MBeans.
37 *
38 * <p>The {@link javax.management.ObjectName ObjectName} for uniquely identifying
39 * the diagnostic MBean within an MBeanServer is:
40 * <blockquote>
41 * {@code com.sun.management:type=DiagnosticCommand}
42 * </blockquote>
43 *
44 * <p>This MBean is a {@link javax.management.DynamicMBean DynamicMBean}
45 * and also a {@link javax.management.NotificationEmitter}.
46 * The {@code DiagnosticCommandMBean} is generated at runtime and is subject to
47 * modifications during the lifetime of the Java virtual machine.
48 *
49 * A <em>diagnostic command</em> is represented as an operation of
50 * the {@code DiagnosticCommandMBean} interface. Each diagnostic command has:
51 * <ul>
52 * <li>the diagnostic command name which is the name being referenced in
53 * the HotSpot Virtual Machine</li>
54 * <li>the MBean operation name which is the
55 * {@linkplain javax.management.MBeanOperationInfo#getName() name}
56 * generated for the diagnostic command operation invocation.
57 * The MBean operation name is implementation dependent</li>
58 * </ul>
59 *
60 * The recommended way to transform a diagnostic command name into a MBean
61 * operation name is as follows:
62 * <ul>
63 * <li>All characters from the first one to the first dot are set to be
64 * lower-case characters</li>
65 * <li>Every dot or underline character is removed and the following
66 * character is set to be an upper-case character</li>
67 * <li>All other characters are copied without modification</li>
68 * </ul>
69 *
70 * <p>The diagnostic command name is always provided with the meta-data on the
71 * operation in a field named {@code dcmd.name} (see below).
72 *
73 * <p>A diagnostic command may or may not support options or arguments.
74 * All the operations return {@code String} and either take
75 * no parameter for operations that do not support any option or argument,
76 * or take a {@code String[]} parameter for operations that support at least
77 * one option or argument.
78 * Each option or argument must be stored in a single String.
79 * Options or arguments split across several String instances are not supported.
80 *
81 * <p>The distinction between options and arguments: options are identified by
82 * the option name while arguments are identified by their position in the
83 * command line. Options and arguments are processed in the order of the array
84 * passed to the invocation method.
85 *
86 * <p>Like any operation of a dynamic MBean, each of these operations is
87 * described by {@link javax.management.MBeanOperationInfo MBeanOperationInfo}
88 * instance. Here's the values returned by this object:
89 * <ul>
90 * <li>{@link javax.management.MBeanOperationInfo#getName() getName()}
91 * returns the operation name generated from the diagnostic command name</li>
92 * <li>{@link javax.management.MBeanOperationInfo#getDescription() getDescription()}
93 * returns the diagnostic command description
94 * (the same as the one return in the 'help' command)</li>
95 * <li>{@link javax.management.MBeanOperationInfo#getImpact() getImpact()}
96 * returns {@code ACTION_INFO}</li>
97 * <li>{@link javax.management.MBeanOperationInfo#getReturnType() getReturnType()}
98 * returns {@code java.lang.String}</li>
99 * <li>{@link javax.management.MBeanOperationInfo#getDescriptor() getDescriptor()}
100 * returns a Descriptor instance (see below)</li>
101 * </ul>
102 *
103 * <p>The {@link javax.management.Descriptor Descriptor}
104 * is a collection of fields containing additional
105 * meta-data for a JMX element. A field is a name and an associated value.
106 * The additional meta-data provided for an operation associated with a
107 * diagnostic command are described in the table below:
108 *
109 * <table class="striped"><caption style="display:none">description</caption>
110 * <thead>
111 * <tr>
112 * <th scope="col">Name</th><th scope="col">Type</th><th scope="col">Description</th>
113 * </tr>
114 * </thead>
115 * <tbody>
116 * <tr>
117 * <th scope="row">dcmd.name</th><td>String</td>
118 * <td>The original diagnostic command name (not the operation name)</td>
119 * </tr>
120 * <tr>
121 * <th scope="row">dcmd.description</th><td>String</td>
122 * <td>The diagnostic command description</td>
123 * </tr>
124 * <tr>
125 * <th scope="row">dcmd.help</th><td>String</td>
126 * <td>The full help message for this diagnostic command (same output as
127 * the one produced by the 'help' command)</td>
128 * </tr>
129 * <tr>
130 * <th scope="row">dcmd.vmImpact</th><td>String</td>
131 * <td>The impact of the diagnostic command,
132 * this value is the same as the one printed in the 'impact'
133 * section of the help message of the diagnostic command, and it
134 * is different from the getImpact() of the MBeanOperationInfo</td>
135 * </tr>
136 * <tr>
137 * <th scope="row">dcmd.enabled</th><td>boolean</td>
138 * <td>True if the diagnostic command is enabled, false otherwise</td>
139 * </tr>
140 * <tr>
141 * <th scope="row">dcmd.permissionClass</th><td>String</td>
142 * <td>Some diagnostic command might require a specific permission to be
143 * executed, in addition to the MBeanPermission to invoke their
144 * associated MBean operation. This field returns the fully qualified
145 * name of the permission class or null if no permission is required
146 * </td>
147 * </tr>
148 * <tr>
149 * <th scope="row">dcmd.permissionName</th><td>String</td>
150 * <td>The fist argument of the permission required to execute this
151 * diagnostic command or null if no permission is required</td>
152 * </tr>
153 * <tr>
154 * <th scope="row">dcmd.permissionAction</th><td>String</td>
155 * <td>The second argument of the permission required to execute this
156 * diagnostic command or null if the permission constructor has only
157 * one argument (like the ManagementPermission) or if no permission
158 * is required</td>
159 * </tr>
160 * <tr>
161 * <th scope="row">dcmd.arguments</th><td>Descriptor</td>
162 * <td>A Descriptor instance containing the descriptions of options and
163 * arguments supported by the diagnostic command (see below)</td>
164 * </tr>
165 * </tbody>
166 * </table>
167 *
168 * <p>The description of parameters (options or arguments) of a diagnostic
169 * command is provided within a Descriptor instance. In this Descriptor,
170 * each field name is a parameter name, and each field value is itself
171 * a Descriptor instance. The fields provided in this second Descriptor
172 * instance are described in the table below:
173 *
174 * <table class="striped"><caption style="display:none">description</caption>
175 * <thead>
176 * <tr>
177 * <th scope="col">Name</th><th scope="col">Type</th><th scope="col">Description</th>
178 * </tr>
179 * </thead>
180 * <tbody>
181 * <tr>
182 * <th scope="row">dcmd.arg.name</th><td>String</td>
183 * <td>The name of the parameter</td>
184 * </tr>
185 * <tr>
186 * <th scope="row">dcmd.arg.type</th><td>String</td>
187 * <td>The type of the parameter. The returned String is the name of a type
188 * recognized by the diagnostic command parser. These types are not
189 * Java types and are implementation dependent.
190 * </td>
191 * </tr>
192 * <tr>
193 * <th scope="row">dcmd.arg.description</th><td>String</td>
194 * <td>The parameter description</td>
195 * </tr>
196 * <tr>
197 * <th scope="row">dcmd.arg.isMandatory</th><td>boolean</td>
198 * <td>True if the parameter is mandatory, false otherwise</td>
199 * </tr>
200 * <tr>
201 * <th scope="row">dcmd.arg.isOption</th><td>boolean</td>
202 * <td>True if the parameter is an option, false if it is an argument</td>
203 * </tr>
204 * <tr>
205 * <th scope="row">dcmd.arg.isMultiple</th><td>boolean</td>
206 * <td>True if the parameter can be specified several times, false
207 * otherwise</td>
208 * </tr>
209 * </tbody>
210 * </table>
211 *
212 * <p>When the set of diagnostic commands currently supported by the Java
213 * Virtual Machine is modified, the {@code DiagnosticCommandMBean} emits
214 * a {@link javax.management.Notification} with a
215 * {@linkplain javax.management.Notification#getType() type} of
216 * <a href="{@docRoot}/java.management/javax/management/MBeanInfo.html#info-changed">
217 * {@code "jmx.mbean.info.changed"}</a> and a
218 * {@linkplain javax.management.Notification#getUserData() userData} that
219 * is the new {@code MBeanInfo}.
220 *
221 * @since 1.8
222 */
223 public interface DiagnosticCommandMBean extends DynamicMBean
224 {
225
226 }