1 /*

     2  * Copyright (c) 1999, 2006, 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 javax.management;

    27 

    28 

    29 import java.util.List;

    30 import java.util.Vector;

    31 

    32 /**

    33  * Provides an implementation of the {@link javax.management.NotificationFilter} interface.

    34  * The filtering is performed on the notification type attribute.

    35  * <P>

    36  * Manages a list of enabled notification types.

    37  * A method allows users to enable/disable as many notification types as required.

    38  * <P>

    39  * Then, before sending a notification to a listener registered with a filter,

    40  * the notification broadcaster compares this notification type with all notification types

    41  * enabled by the filter. The notification will be sent to the listener

    42  * only if its filter enables this notification type.

    43  * <P>

    44  * Example:

    45  * <BLOCKQUOTE>

    46  * <PRE>

    47  * NotificationFilterSupport myFilter = new NotificationFilterSupport();

    48  * myFilter.enableType("my_example.my_type");

    49  * myBroadcaster.addListener(myListener, myFilter, null);

    50  * </PRE>

    51  * </BLOCKQUOTE>

    52  * The listener <CODE>myListener</CODE> will only receive notifications the type of which equals/starts with "my_example.my_type".

    53  *

    54  * @see javax.management.NotificationBroadcaster#addNotificationListener

    55  *

    56  * @since 1.5

    57  */

    58 public class NotificationFilterSupport implements NotificationFilter {

    59 

    60     /* Serial version */

    61     private static final long serialVersionUID = 6579080007561786969L;

    62 

    63     /**

    64      * @serial {@link Vector} that contains the enabled notification types.

    65      *         The default value is an empty vector.

    66      */

    67     private List<String> enabledTypes = new Vector<String>();

    68 

    69 

    70     /**

    71      * Invoked before sending the specified notification to the listener.

    72      * <BR>This filter compares the type of the specified notification with each enabled type.

    73      * If the notification type matches one of the enabled types,

    74      * the notification should be sent to the listener and this method returns <CODE>true</CODE>.

    75      *

    76      * @param notification The notification to be sent.

    77      * @return <CODE>true</CODE> if the notification should be sent to the listener, <CODE>false</CODE> otherwise.

    78      */

    79     public synchronized boolean isNotificationEnabled(Notification notification) {

    80 

    81         String type = notification.getType();

    82 

    83         if (type == null) {

    84             return false;

    85         }

    86         try {

    87             for (String prefix : enabledTypes) {

    88                 if (type.startsWith(prefix)) {

    89                     return true;

    90                 }

    91             }

    92         } catch (java.lang.NullPointerException e) {

    93             // Should never occurs...

    94             return false;

    95         }

    96         return false;

    97     }

    98 

    99     /**

   100      * Enables all the notifications the type of which starts with the specified prefix

   101      * to be sent to the listener.

   102      * <BR>If the specified prefix is already in the list of enabled notification types,

   103      * this method has no effect.

   104      * <P>

   105      * Example:

   106      * <BLOCKQUOTE>

   107      * <PRE>

   108      * // Enables all notifications the type of which starts with "my_example" to be sent.

   109      * myFilter.enableType("my_example");

   110      * // Enables all notifications the type of which is "my_example.my_type" to be sent.

   111      * myFilter.enableType("my_example.my_type");

   112      * </PRE>

   113      * </BLOCKQUOTE>

   114      *

   115      * Note that:

   116      * <BLOCKQUOTE><CODE>

   117      * myFilter.enableType("my_example.*");

   118      * </CODE></BLOCKQUOTE>

   119      * will no match any notification type.

   120      *

   121      * @param prefix The prefix.

   122      * @exception java.lang.IllegalArgumentException The prefix parameter is null.

   123      */

   124     public synchronized void enableType(String prefix)

   125             throws IllegalArgumentException {

   126 

   127         if (prefix == null) {

   128             throw new IllegalArgumentException("The prefix cannot be null.");

   129         }

   130         if (!enabledTypes.contains(prefix)) {

   131             enabledTypes.add(prefix);

   132         }

   133     }

   134 

   135     /**

   136      * Removes the given prefix from the prefix list.

   137      * <BR>If the specified prefix is not in the list of enabled notification types,

   138      * this method has no effect.

   139      *

   140      * @param prefix The prefix.

   141      */

   142     public synchronized void disableType(String prefix) {

   143         enabledTypes.remove(prefix);

   144     }

   145 

   146     /**

   147      * Disables all notification types.

   148      */

   149     public synchronized void disableAllTypes() {

   150         enabledTypes.clear();

   151     }

   152 

   153 

   154     /**

   155      * Gets all the enabled notification types for this filter.

   156      *

   157      * @return The list containing all the enabled notification types.

   158      */

   159     public synchronized Vector<String> getEnabledTypes() {

   160         return (Vector<String>)enabledTypes;

   161     }

   162 

   163 }