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.camel.component.vm;
018    
019    import java.util.HashMap;
020    import java.util.Map;
021    import java.util.concurrent.BlockingQueue;
022    
023    import org.apache.camel.Endpoint;
024    import org.apache.camel.Exchange;
025    import org.apache.camel.component.seda.SedaComponent;
026    import org.apache.camel.component.seda.SedaEndpoint;
027    
028    /**
029     * An implementation of the <a href="http://activemq.apache.org/camel/vm.html">VM components</a>
030     * for asynchronous SEDA exchanges on a {@link BlockingQueue} within the classloader tree containing
031     * the camel-core.jar. i.e. to handle communicating across CamelContext instances and possibly across
032     * web application contexts, providing that camel-core.jar is on the system classpath.
033     *
034     * @version $Revision: 1.1 $
035     */
036    public class VmComponent<E extends Exchange> extends SedaComponent<E> {
037        protected static Map<String, BlockingQueue<Exchange>> queues = new HashMap<String, BlockingQueue<Exchange>>();
038    
039        @Override
040        protected Endpoint<E> createEndpoint(String uri, String remaining, Map parameters) throws Exception {
041            BlockingQueue<E> blockingQueue = (BlockingQueue<E>) getBlockingQueue(uri);
042            return new SedaEndpoint<E>(uri, this, blockingQueue);
043        }
044    
045        protected BlockingQueue<Exchange> getBlockingQueue(String uri) {
046            synchronized (queues) {
047                BlockingQueue<Exchange> answer = queues.get(uri);
048                if (answer == null) {
049                    answer = (BlockingQueue<Exchange>) createQueue();
050                    queues.put(uri, answer);
051                }
052                return answer;
053            }
054        }
055    }