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 import java.util.concurrent.atomic.AtomicInteger; 023 024 import org.apache.camel.Endpoint; 025 import org.apache.camel.Exchange; 026 import org.apache.camel.component.seda.SedaComponent; 027 import org.apache.camel.component.seda.SedaEndpoint; 028 029 /** 030 * An implementation of the <a href="http://activemq.apache.org/camel/vm.html">VM components</a> 031 * for asynchronous SEDA exchanges on a {@link BlockingQueue} within the classloader tree containing 032 * the camel-core.jar. i.e. to handle communicating across CamelContext instances and possibly across 033 * web application contexts, providing that camel-core.jar is on the system classpath. 034 * 035 * @version $Revision: 36321 $ 036 */ 037 public class VmComponent extends SedaComponent { 038 protected static Map<String, BlockingQueue> queues = new HashMap<String, BlockingQueue>(); 039 private static final AtomicInteger START_COUNTER = new AtomicInteger(); 040 041 042 @Override 043 protected Endpoint createEndpoint(String uri, String remaining, Map parameters) throws Exception { 044 BlockingQueue<Exchange> blockingQueue = getBlockingQueue(uri, parameters); 045 return new SedaEndpoint(uri, this, blockingQueue); 046 } 047 048 protected BlockingQueue<Exchange> getBlockingQueue(String uri, Map parameters) { 049 synchronized (queues) { 050 BlockingQueue<Exchange> answer = queues.get(uri); 051 if (answer == null) { 052 answer = createQueue(uri, parameters); 053 queues.put(uri, answer); 054 } 055 return answer; 056 } 057 } 058 059 @Override 060 protected void doStart() throws Exception { 061 super.doStart(); 062 START_COUNTER.incrementAndGet(); 063 } 064 065 @Override 066 protected void doStop() throws Exception { 067 super.doStop(); 068 if (START_COUNTER.decrementAndGet() == 0) { 069 synchronized (queues) { 070 for (BlockingQueue q : queues.values()) { 071 q.clear(); 072 } 073 queues.clear(); 074 } 075 } 076 } 077 078 }