001/* MBeanServerDelegate.java -- The management server delegate.
002   Copyright (C) 2006 Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038package javax.management;
039
040import gnu.javax.management.ListenerData;
041import gnu.classpath.SystemProperties;
042
043import java.net.InetAddress;
044import java.net.UnknownHostException;
045
046import java.util.ArrayList;
047import java.util.Date;
048import java.util.Iterator;
049import java.util.List;
050
051/**
052 * Provides an implementation of a delegate bean, which is associated
053 * with a management server.  The delegate bean is responsible
054 * for providing metadata about the server and handling the
055 * registration and deregistration notifications.
056 *
057 * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
058 * @since 1.5
059 */
060public class MBeanServerDelegate
061  implements MBeanServerDelegateMBean, NotificationEmitter
062{
063
064  /**
065   * The identifier of the server associated with this delegate.
066   */
067  private String id;
068
069  /**
070   * The listeners registered with the delegate.
071   */
072  private final List<ListenerData> listeners =
073    new ArrayList<ListenerData>();
074
075  /**
076   * The sequence identifier used by the delegate.
077   */
078  private long seqNo;
079
080  /**
081   * Default constructor which generates the id.
082   */
083  public MBeanServerDelegate()
084  {
085    String hostName;
086    try
087      {
088        hostName = InetAddress.getLocalHost().getHostName();
089      }
090    catch (UnknownHostException e)
091      {
092        hostName = "Unknown host";
093      }
094    id = hostName + "_" + new Date().getTime();
095  }
096
097  /**
098   * Registers the specified listener as a new recipient of
099   * notifications from the delegate.  If non-null, the filter
100   * argument will be used to select which notifications are
101   * delivered.  The supplied object will also be passed to
102   * the recipient with each notification.  This should not
103   * be modified by the broadcaster, but instead should be
104   * passed unmodified to the listener.
105   *
106   * @param listener the new listener, who will receive
107   *                 notifications from this broadcasting bean.
108   * @param filter a filter to determine which notifications are
109   *               delivered to the listener, or <code>null</code>
110   *               if no filtering is required.
111   * @param passback an object to be passed to the listener with
112   *                 each notification.
113   * @throws IllegalArgumentException if <code>listener</code> is
114   *                                  <code>null</code>.
115   * @see #removeNotificationListener(NotificationListener)
116   */
117  public void addNotificationListener(NotificationListener listener,
118                                      NotificationFilter filter,
119                                      Object passback)
120    throws IllegalArgumentException
121  {
122    if (listener == null)
123      throw new IllegalArgumentException("A null listener was supplied.");
124    listeners.add(new ListenerData(listener, filter, passback));
125  }
126
127  /**
128   * Returns the name of this Java Management eXtensions (JMX) implementation.
129   *
130   * @return the implementation name.
131   */
132  public String getImplementationName()
133  {
134    return "GNU JMX";
135  }
136
137  /**
138   * Returns the vendor of this Java Management eXtensions (JMX) implementation.
139   *
140   * @return the implementation vendor.
141   */
142  public String getImplementationVendor()
143  {
144    return "The GNU Classpath Project";
145  }
146
147  /**
148   * Returns the version of this Java Management eXtensions (JMX) implementation.
149   *
150   * @return the implementation version.
151   */
152  public String getImplementationVersion()
153  {
154    return SystemProperties.getProperty("gnu.classpath.version");
155  }
156
157  /**
158   * Returns the unique identifier for this management server.
159   *
160   * @return the unique id of the server.
161   */
162  public String getMBeanServerId()
163  {
164    return id;
165  }
166
167  /**
168   * Returns an array describing the notifications this
169   * bean may send to its registered listeners.  Ideally, this
170   * array should be complete, but in some cases, this may
171   * not be possible.  However, be aware that some listeners
172   * may expect this to be so.
173   *
174   * @return the array of possible notifications.
175   */
176  public MBeanNotificationInfo[] getNotificationInfo()
177  {
178    return new MBeanNotificationInfo[] 
179      {
180        new MBeanNotificationInfo(new String[]
181          {
182            MBeanServerNotification.REGISTRATION_NOTIFICATION,
183            MBeanServerNotification.UNREGISTRATION_NOTIFICATION,
184          },
185                                  MBeanServerNotification.class.getName(),
186                                  "Server registration notifications")
187      };
188  }
189
190  /**
191   * Returns the name of this Java Management eXtensions (JMX) specification.
192   *
193   * @return the specification name.
194   */
195  public String getSpecificationName()
196  {
197    return "JMX";
198  }
199
200
201  /**
202   * Returns the vendor of this Java Management eXtensions (JMX) specification.
203   *
204   * @return the specification vendor.
205   */
206  public String getSpecificationVendor()
207  {
208    return "Sun Microsystems";
209  }
210
211  /**
212   * Returns the version of this Java Management eXtensions (JMX) specification.
213   *
214   * @return the specification version.
215   */
216  public String getSpecificationVersion()
217  {
218    return "1.2";
219  }
220
221  /**
222   * Removes the specified listener from the list of recipients
223   * of notifications from this bean.  This includes all combinations
224   * of filters and passback objects registered for this listener.
225   * For more specific removal of listeners, see
226   * {@link #removeNotificationListener(NotificationListener,
227   * NotificationFilter, java.lang.Object)}
228   *
229   * @param listener the listener to remove.
230   * @throws ListenerNotFoundException if the specified listener
231   *                                   is not registered with this bean.
232   * @see #addNotificationListener(NotificationListener, NotificationFilter,
233   *                               java.lang.Object)
234   */
235  public void removeNotificationListener(NotificationListener listener)
236    throws ListenerNotFoundException
237  {
238    Iterator<ListenerData> it = listeners.iterator();
239    boolean foundOne = false;
240    while (it.hasNext())
241      {
242        if (it.next().getListener() == listener)
243          {
244            it.remove();
245            foundOne = true;
246          }
247      }
248    if (!foundOne)
249      throw new ListenerNotFoundException("The specified listener, " + listener +
250                                          "is not registered with this bean.");
251  }
252
253  /**
254   * Removes the specified listener from the list of recipients
255   * of notifications from this delegate.  Only the first instance with
256   * the supplied filter and passback object is removed.
257   * <code>null</code> is used as a valid value for these parameters,
258   * rather than as a way to remove all registration instances for
259   * the specified listener; for this behaviour instead, see
260   * {@link #removeNotificationListener(NotificationListener)}.
261   *
262   * @param listener the listener to remove.
263   * @param filter the filter of the listener to remove.
264   * @param passback the passback object of the listener to remove.
265   * @throws ListenerNotFoundException if the specified listener
266   *                                   is not registered with this bean.
267   * @see #addNotificationListener(NotificationListener, NotificationFilter,
268   *                               java.lang.Object)
269   * @see #removeNotificationListener(NotificationListener)
270   */
271  public void removeNotificationListener(NotificationListener listener,
272                                         NotificationFilter filter,
273                                         Object passback)
274    throws ListenerNotFoundException
275  {
276    if (!(listeners.remove(new ListenerData(listener, filter, passback))))
277      {
278        throw new ListenerNotFoundException("The specified listener, " + listener +
279                                            " with filter " + filter + 
280                                            "and passback " + passback + 
281                                            ", is not registered with this bean.");
282      }
283  }
284
285  /**
286   * Allows the server to use the delegate to send a notification.
287   * If the supplied notification has a sequence number <= 0, then
288   * it is replaced with the delegate's own sequence number.
289   *
290   * @param notification the notification to send.
291   */
292  public void sendNotification(Notification notification)
293  {
294    if (notification.getSequenceNumber() <= 0)
295      notification.setSequenceNumber(++seqNo);
296    for (ListenerData ldata : listeners)
297      {
298        NotificationFilter filter = ldata.getFilter();
299        if (filter == null || filter.isNotificationEnabled(notification))
300          ldata.getListener().handleNotification(notification, ldata.getPassback());
301      }
302  }
303
304}