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    /**
021     * Represents a clustered invocation.
022     * <p>
023     * A clustered invocation is intended to be a thin wrapper around an actual invocation enhancing this latter with
024     * an association to a local SessionManager. For instance, an HTTPRequest is an actual invocation.
025     * <p> 
026     * A clustered invocation is interposed between a client and the Session he wants to access to provide cluster wide
027     * access serialization to the requested Session. A clustered invocation is associated to a local SessionManager, even
028     * if no contract captures such a relationship. When a clustered invocation is executed one of the two following 
029     * scenarios happen:
030     * <ul>
031     * <li>the clustered invocation is executed locally. A local execution implies that the local SessionManager associated
032     * to the clustered invocation is owning the Session (may be after a migration); or</li>
033     * <li>the clustered invocation is executed remotely on the Node where the Session is being owned.</li>
034     * </ul>
035     *
036     * @version $Rev: 706640 $ $Date: 2008-10-21 14:44:05 +0000 (Tue, 21 Oct 2008) $
037     */
038    public interface ClusteredInvocation {
039        
040        /**
041         * Invokes the clustered invocation.
042         * 
043         * @throws ClusteredInvocationException Thrown when the invocation cannot be successfully executed. This may
044         * be either due to the fact that the actual invocation has failed or the requestedSessionId is unknown by
045         * the associated local SessionManager and its remote peers.
046         */
047        void invoke() throws ClusteredInvocationException;
048        
049        /**
050         * Gets the sessionId of the Session bound to the invocation represented by this instance.
051         *  
052         * @return sessionId of the targeted Session.
053         */
054        String getRequestedSessionId();
055        
056    }