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| 1 | +/* | |
| 2 | + * Copyright (c) 2006, 2007, 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.tools.jconsole; | |
| 27 | + | |
| 28 | +import java.beans.PropertyChangeEvent; | |
| 29 | +import java.beans.PropertyChangeListener; | |
| 30 | +import java.util.ArrayList; | |
| 31 | +import java.util.List; | |
| 32 | +import javax.swing.JPanel; | |
| 33 | +import javax.swing.SwingWorker; | |
| 34 | + | |
| 35 | +/** | |
| 36 | + * A JConsole plugin class. JConsole uses the | |
| 37 | + * <a href="{@docRoot}/../../../../api/java/util/ServiceLoader.html"> | |
| 38 | + * service provider</a> mechanism to search the JConsole plugins. | |
| 39 | + * Users can provide their JConsole plugins in a jar file | |
| 40 | + * containing a file named | |
| 41 | + * | |
| 42 | + * <blockquote><pre> | |
| 43 | + * META-INF/services/com.sun.tools.jconsole.JConsolePlugin</pre></blockquote> | |
| 44 | + * | |
| 45 | + * <p> This file contains one line for each plugin, for example, | |
| 46 | + * | |
| 47 | + * <blockquote><pre> | |
| 48 | + * com.sun.example.JTop</pre></blockquote> | |
| 49 | + * <p> which is the fully qualified class name of the class implementing | |
| 50 | + * {@code JConsolePlugin}. | |
| 51 | + * | |
| 52 | + * <p> To load the JConsole plugins in JConsole, run: | |
| 53 | + * | |
| 54 | + * <blockquote><pre> | |
| 55 | + * jconsole -pluginpath <plugin-path> </pre></blockquote> | |
| 56 | + * | |
| 57 | + * <p> where <tt><plugin-path></tt> specifies the paths of JConsole | |
| 58 | + * plugins to look up which can be a directory or a jar file. Multiple | |
| 59 | + * paths are separated by the path separator character of the platform. | |
| 60 | + * | |
| 61 | + * <p> When a new JConsole window is created for a connection, | |
| 62 | + * an instance of each {@code JConsolePlugin} will be created. | |
| 63 | + * The {@code JConsoleContext} object is not available at its | |
| 64 | + * construction time. | |
| 65 | + * JConsole will set the {@link JConsoleContext} object for | |
| 66 | + * a plugin after the plugin object is created. It will then | |
| 67 | + * call its {@link #getTabs getTabs} method and add the returned | |
| 68 | + * tabs to the JConsole window. | |
| 69 | + * | |
| 70 | + * @see <a href="{@docRoot}/../../../../api/java/util/ServiceLoader.html"> | |
| 71 | + * java.util.ServiceLoader</a> | |
| 72 | + * | |
| 73 | + * @since 1.6 | |
| 74 | + */ | |
| 75 | +public abstract class JConsolePlugin { | |
| 76 | + private volatile JConsoleContext context = null; | |
| 77 | + private List<PropertyChangeListener> listeners = null; | |
| 78 | + | |
| 79 | + /** | |
| 80 | + * Constructor. | |
| 81 | + */ | |
| 82 | + protected JConsolePlugin() { | |
| 83 | + } | |
| 84 | + | |
| 85 | + /** | |
| 86 | + * Sets the {@link JConsoleContext JConsoleContext} object representing | |
| 87 | + * the connection to an application. This method will be called | |
| 88 | + * only once after the plugin is created and before the {@link #getTabs} | |
| 89 | + * is called. The given {@code context} can be in any | |
| 90 | + * {@link JConsoleContext#getConnectionState connection state} when | |
| 91 | + * this method is called. | |
| 92 | + * | |
| 93 | + * @param context a {@code JConsoleContext} object | |
| 94 | + */ | |
| 95 | + public final synchronized void setContext(JConsoleContext context) { | |
| 96 | + this.context = context; | |
| 97 | + if (listeners != null) { | |
| 98 | + for (PropertyChangeListener l : listeners) { | |
| 99 | + context.addPropertyChangeListener(l); | |
| 100 | + } | |
| 101 | + // throw away the listener list | |
| 102 | + listeners = null; | |
| 103 | + } | |
| 104 | + } | |
| 105 | + | |
| 106 | + /** | |
| 107 | + * Returns the {@link JConsoleContext JConsoleContext} object representing | |
| 108 | + * the connection to an application. This method may return <tt>null</tt> | |
| 109 | + * if it is called before the {@link #setContext context} is initialized. | |
| 110 | + * | |
| 111 | + * @return the {@link JConsoleContext JConsoleContext} object representing | |
| 112 | + * the connection to an application. | |
| 113 | + */ | |
| 114 | + public final JConsoleContext getContext() { | |
| 115 | + return context; | |
| 116 | + } | |
| 117 | + | |
| 118 | + /** | |
| 119 | + * Returns the tabs to be added in JConsole window. | |
| 120 | + * <p> | |
| 121 | + * The returned map contains one entry for each tab | |
| 122 | + * to be added in the tabbed pane in a JConsole window with | |
| 123 | + * the tab name as the key | |
| 124 | + * and the {@link JPanel} object as the value. | |
| 125 | + * This method returns an empty map if no tab is added by this plugin. | |
| 126 | + * This method will be called from the <i>Event Dispatch Thread</i> | |
| 127 | + * once at the new connection time. | |
| 128 | + * | |
| 129 | + * @return a map of a tab name and a {@link JPanel} object | |
| 130 | + * representing the tabs to be added in the JConsole window; | |
| 131 | + * or an empty map. | |
| 132 | + */ | |
| 133 | + public abstract java.util.Map<String, JPanel> getTabs(); | |
| 134 | + | |
| 135 | + /** | |
| 136 | + * Returns a {@link SwingWorker} to perform | |
| 137 | + * the GUI update for this plugin at the same interval | |
| 138 | + * as JConsole updates the GUI. | |
| 139 | + * <p> | |
| 140 | + * JConsole schedules the GUI update at an interval specified | |
| 141 | + * for a connection. This method will be called at every | |
| 142 | + * update to obtain a {@code SwingWorker} for each plugin. | |
| 143 | + * <p> | |
| 144 | + * JConsole will invoke the {@link SwingWorker#execute execute()} | |
| 145 | + * method to schedule the returned {@code SwingWorker} for execution | |
| 146 | + * if: | |
| 147 | + * <ul> | |
| 148 | + * <li> the <tt>SwingWorker</tt> object has not been executed | |
| 149 | + * (i.e. the {@link SwingWorker#getState} method | |
| 150 | + * returns {@link javax.swing.SwingWorker.StateValue#PENDING PENDING} | |
| 151 | + * state); and</li> | |
| 152 | + * <li> the <tt>SwingWorker</tt> object returned in the previous | |
| 153 | + * update has completed the task if it was not <tt>null</tt> | |
| 154 | + * (i.e. the {@link SwingWorker#isDone SwingWorker.isDone} method | |
| 155 | + * returns <tt>true</tt>).</li> | |
| 156 | + * </ul> | |
| 157 | + * <br> | |
| 158 | + * Otherwise, <tt>SwingWorker</tt> object will not be scheduled to work. | |
| 159 | + * | |
| 160 | + * <p> | |
| 161 | + * A plugin can schedule its own GUI update and this method | |
| 162 | + * will return <tt>null</tt>. | |
| 163 | + * | |
| 164 | + * @return a <tt>SwingWorker</tt> to perform the GUI update; or | |
| 165 | + * <tt>null</tt>. | |
| 166 | + */ | |
| 167 | + public abstract SwingWorker<?,?> newSwingWorker(); | |
| 168 | + | |
| 169 | + /** | |
| 170 | + * Dispose this plugin. This method is called by JConsole to inform | |
| 171 | + * that this plugin will be discarded and that it should free | |
| 172 | + * any resources that it has allocated. | |
| 173 | + * The {@link #getContext JConsoleContext} can be in any | |
| 174 | + * {@link JConsoleContext#getConnectionState connection state} when | |
| 175 | + * this method is called. | |
| 176 | + */ | |
| 177 | + public void dispose() { | |
| 178 | + // Default nop implementation | |
| 179 | + } | |
| 180 | + | |
| 181 | + /** | |
| 182 | + * Adds a {@link PropertyChangeListener PropertyChangeListener} | |
| 183 | + * to the {@link #getContext JConsoleContext} object for this plugin. | |
| 184 | + * This method is a convenient method for this plugin to register | |
| 185 | + * a listener when the {@code JConsoleContext} object may or | |
| 186 | + * may not be available. | |
| 187 | + * | |
| 188 | + * <p>For example, a plugin constructor can | |
| 189 | + * call this method to register a listener to listen to the | |
| 190 | + * {@link JConsoleContext.ConnectionState connectionState} | |
| 191 | + * property changes and the listener will be added to the | |
| 192 | + * {@link JConsoleContext#addPropertyChangeListener JConsoleContext} | |
| 193 | + * object when it is available. | |
| 194 | + * | |
| 195 | + * @param listener The {@code PropertyChangeListener} to be added | |
| 196 | + * | |
| 197 | + * @throws NullPointerException if {@code listener} is {@code null}. | |
| 198 | + */ | |
| 199 | + public final void addContextPropertyChangeListener(PropertyChangeListener listener) { | |
| 200 | + if (listener == null) { | |
| 201 | + throw new NullPointerException("listener is null"); | |
| 202 | + } | |
| 203 | + | |
| 204 | + if (context == null) { | |
| 205 | + // defer registration of the listener until setContext() is called | |
| 206 | + synchronized (this) { | |
| 207 | + // check again if context is not set | |
| 208 | + if (context == null) { | |
| 209 | + // maintain a listener list to be added later | |
| 210 | + if (listeners == null) { | |
| 211 | + listeners = new ArrayList<PropertyChangeListener>(); | |
| 212 | + } | |
| 213 | + listeners.add(listener); | |
| 214 | + return; | |
| 215 | + } | |
| 216 | + } | |
| 217 | + } | |
| 218 | + context.addPropertyChangeListener(listener); | |
| 219 | + } | |
| 220 | + | |
| 221 | + /** | |
| 222 | + * Removes a {@link PropertyChangeListener PropertyChangeListener} | |
| 223 | + * from the listener list of the {@link #getContext JConsoleContext} | |
| 224 | + * object for this plugin. | |
| 225 | + * If {@code listener} was never added, no exception is | |
| 226 | + * thrown and no action is taken. | |
| 227 | + * | |
| 228 | + * @param listener the {@code PropertyChangeListener} to be removed | |
| 229 | + * | |
| 230 | + * @throws NullPointerException if {@code listener} is {@code null}. | |
| 231 | + */ | |
| 232 | + public final void removeContextPropertyChangeListener(PropertyChangeListener listener) { | |
| 233 | + if (listener == null) { | |
| 234 | + throw new NullPointerException("listener is null"); | |
| 235 | + } | |
| 236 | + | |
| 237 | + if (context == null) { | |
| 238 | + // defer registration of the listener until setContext() is called | |
| 239 | + synchronized (this) { | |
| 240 | + // check again if context is not set | |
| 241 | + if (context == null) { | |
| 242 | + if (listeners != null) { | |
| 243 | + listeners.remove(listener); | |
| 244 | + } | |
| 245 | + return; | |
| 246 | + } | |
| 247 | + } | |
| 248 | + } | |
| 249 | + context.removePropertyChangeListener(listener); | |
| 250 | + } | |
| 251 | +} | |