001    /**
002     *  Licensed to the Apache Software Foundation (ASF) under one or more
003     *  contributor license agreements.  See the NOTICE file distributed with
004     *  this work for additional information regarding copyright ownership.
005     *  The ASF licenses this file to You under the Apache License, Version 2.0
006     *  (the "License"); you may not use this file except in compliance with
007     *  the License.  You may obtain a copy of the License at
008     *
009     *     http://www.apache.org/licenses/LICENSE-2.0
010     *
011     *  Unless required by applicable law or agreed to in writing, software
012     *  distributed under the License is distributed on an "AS IS" BASIS,
013     *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     *  See the License for the specific language governing permissions and
015     *  limitations under the License.
016     */
017    package org.apache.geronimo.clustering;
018    
019    /**
020     * Callback listener for inbound and outbound Session migration.
021     * <p>
022     * A Session is preemptively moved between its associated set of SessionManagers. For instance, when a 
023     * ClusteredInvocation for a given Session is invoked on a Node where the local SessionManager, RequestingSM, does not 
024     * own the targeted Session, the SessionManager owning the Session, OwningSM, the Session may be moved from OwningSM
025     * to RequestingSM. OwningSM, prior to relinquish the Session, executes notifyOutboundSessionMigration and provides
026     * the Session under migration. RequestingRM, after having acquired the Session ownership, executes 
027     * notifyInboundSessionMigration and provides the Session under migration.
028     * <p>
029     * The typical usage of these migration callbacks are to allow a wrapping SessionManager, e.g. an HTTPSession manager,
030     * to perform bookkeeping operations.
031     *
032     * @version $Rev$ $Date$
033     */
034    public interface SessionListener {
035        
036        /**
037         * Calls when the ownership of the provided Session is acquired by the SessionManager to which this listener
038         * is attached.
039         * 
040         * @param session New Session now owned by the attached SessionManager.
041         */
042        void notifyInboundSessionMigration(Session session);
043        
044        /**
045         * Calls when the ownership of the provided Session is relinquished to another SessionManager.
046         * 
047         * @param session Session now owned by another SessionManager.
048         */
049        void notifyOutboundSessionMigration(Session session);
050        
051        /**
052         * Calls when a Session is destroyed.
053         * 
054         * @param session Destroyed session.
055         */
056        void notifySessionDestruction(Session session);
057    }