001    /**
002     *
003     *  Licensed to the Apache Software Foundation (ASF) under one or more
004     *  contributor license agreements.  See the NOTICE file distributed with
005     *  this work for additional information regarding copyright ownership.
006     *  The ASF licenses this file to You under the Apache License, Version 2.0
007     *  (the "License"); you may not use this file except in compliance with
008     *  the License.  You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     *  Unless required by applicable law or agreed to in writing, software
013     *  distributed under the License is distributed on an "AS IS" BASIS,
014     *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     *  See the License for the specific language governing permissions and
016     *  limitations under the License.
017     */
018    package org.apache.geronimo.clustering;
019    
020    
021    /**
022     * Represents a clustered invocation.
023     * <p>
024     * A clustered invocation is intended to be a thin wrapper around an actual invocation enhancing this latter with
025     * an association to a local SessionManager. For instance, an HTTPRequest is an actual invocation.
026     * <p> 
027     * A clustered invocation is interposed between a client and the Session he wants to access to provide cluster wide
028     * access serialization to the requested Session. A clustered invocation is associated to a local SessionManager, even
029     * if no contract captures such a relationship. When a clustered invocation is executed one of the two following 
030     * scenarios happen:
031     * <ul>
032     * <li>the clustered invocation is executed locally. A local execution implies that the local SessionManager associated
033     * to the clustered invocation is owning the Session (may be after a migration); or</li>
034     * <li>the clustered invocation is executed remotely on the Node where the Session is being owned.</li>
035     * </ul>
036     *
037     * @version $Rev$ $Date$
038     */
039    public interface ClusteredInvocation {
040        
041        /**
042         * Invokes the clustered invocation.
043         * 
044         * @throws ClusteredInvocationException Thrown when the invocation cannot be successfully executed. This may
045         * be either due to the fact that the actual invocation has failed or the requestedSessionId is unknown by
046         * the associated local SessionManager and its remote peers.
047         */
048        void invoke() throws ClusteredInvocationException;
049        
050        /**
051         * Gets the sessionId of the Session bound to the invocation represented by this instance.
052         *  
053         * @return sessionId of the targeted Session.
054         */
055        String getRequestedSessionId();
056        
057    }