001    // Copyright 2004, 2005 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // You may obtain a copy of the License at
006    //
007    //     http://www.apache.org/licenses/LICENSE-2.0
008    //
009    // Unless required by applicable law or agreed to in writing, software
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.hivemind.lib.impl;
016    
017    import java.rmi.RemoteException;
018    
019    import org.apache.hivemind.lib.NameLookup;
020    import org.apache.hivemind.lib.RemoteExceptionCoordinator;
021    
022    /**
023     * Generic EJB proxy for stateless session beans.  Acts as an InvocationHandler
024     * for a dynamic proxy.
025     *
026     * @author Howard Lewis Ship
027     */
028    public abstract class AbstractEJBProxy
029    {
030        private NameLookup _nameLookup;
031        private RemoteExceptionCoordinator _coordinator;
032    
033        protected AbstractEJBProxy(NameLookup nameLookup, RemoteExceptionCoordinator coordinator)
034        {
035            _nameLookup = nameLookup;
036            _coordinator = coordinator;
037        }
038    
039        protected Object _lookup(String name)
040        {
041            return _nameLookup.lookup(name, Object.class);
042        }
043    
044        /**
045         * Clears the home and remote objects after any remote exception. 
046         */
047    
048        protected abstract void _clearCachedReferences();
049            
050            /**
051             * Invoked by the fabricated subclass when a remote exception occurs.
052             * This notifies the {@link RemoteExceptionCoordinator} (which, indirectly,
053             * allows the {@link NameLookup} service to release its JNDI context).
054             * In addition, {@link #_clearCachedReferences()} is invoked.
055             */
056        protected void _handleRemoteException(RemoteException ex)
057        {
058            _clearCachedReferences();
059            _coordinator.fireRemoteExceptionDidOccur(this, ex);
060        }
061    }