/*

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

import java.util.List;

import java.util.Vector;

/**

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

 * The filtering is performed on the notification type attribute.

 * <P>

 * Manages a list of enabled notification types.

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

 * <P>

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

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

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

 * only if its filter enables this notification type.

 * <P>

 * Example:

 * <BLOCKQUOTE>

 * <PRE>

 * NotificationFilterSupport myFilter = new NotificationFilterSupport();

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

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

 * </PRE>

 * </BLOCKQUOTE>

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

 *

 * @see javax.management.NotificationBroadcaster#addNotificationListener

 *

 * @since 1.5

 */

public class NotificationFilterSupport implements NotificationFilter {

    /* Serial version */

    private static final long serialVersionUID = 6579080007561786969L;

    /**

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

     *         The default value is an empty vector.

     */

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

    /**

     * Invoked before sending the specified notification to the listener.

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

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

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

     *

     * @param notification The notification to be sent.

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

     */

    public synchronized boolean isNotificationEnabled(Notification notification) {

        String type = notification.getType();

        if (type == null) {

            return false;

        }

        try {

            for (String prefix : enabledTypes) {

                if (type.startsWith(prefix)) {

                    return true;

                }

            }

        } catch (java.lang.NullPointerException e) {

            // Should never occurs...

            return false;

        }

        return false;

    }

    /**

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

     * to be sent to the listener.

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

     * this method has no effect.

     * <P>

     * Example:

     * <BLOCKQUOTE>

     * <PRE>

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

     * myFilter.enableType("my_example");

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

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

     * </PRE>

     * </BLOCKQUOTE>

     *

     * Note that:

     * <BLOCKQUOTE><CODE>

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

     * </CODE></BLOCKQUOTE>

     * will no match any notification type.

     *

     * @param prefix The prefix.

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

     */

    public synchronized void enableType(String prefix)

            throws IllegalArgumentException {

        if (prefix == null) {

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

        }

        if (!enabledTypes.contains(prefix)) {

            enabledTypes.add(prefix);

        }

    }

    /**

     * Removes the given prefix from the prefix list.

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

     * this method has no effect.

     *

     * @param prefix The prefix.

     */

    public synchronized void disableType(String prefix) {

        enabledTypes.remove(prefix);

    }

    /**

     * Disables all notification types.

     */

    public synchronized void disableAllTypes() {

        enabledTypes.clear();

    }

    /**

     * Gets all the enabled notification types for this filter.

     *

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

     */

    public synchronized Vector<String> getEnabledTypes() {

        return (Vector<String>)enabledTypes;

    }

}