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: 585 $ 036 */ 037 public class VmComponent extends SedaComponent { 038 protected static final Map<String, BlockingQueue> QUEUES = new HashMap<String, BlockingQueue>(); 039 private static final AtomicInteger START_COUNTER = new AtomicInteger(); 040 041 @Override 042 protected Endpoint createEndpoint(String uri, String remaining, Map parameters) throws Exception { 043 BlockingQueue<Exchange> blockingQueue = getBlockingQueue(uri, parameters); 044 return new SedaEndpoint(uri, this, blockingQueue); 045 } 046 047 protected BlockingQueue<Exchange> getBlockingQueue(String uri, Map parameters) { 048 synchronized (QUEUES) { 049 BlockingQueue<Exchange> answer = QUEUES.get(uri); 050 if (answer == null) { 051 answer = createQueue(uri, parameters); 052 QUEUES.put(uri, answer); 053 } 054 return answer; 055 } 056 } 057 058 @Override 059 protected void doStart() throws Exception { 060 super.doStart(); 061 START_COUNTER.incrementAndGet(); 062 } 063 064 @Override 065 protected void doStop() throws Exception { 066 super.doStop(); 067 if (START_COUNTER.decrementAndGet() == 0) { 068 synchronized (QUEUES) { 069 for (BlockingQueue q : QUEUES.values()) { 070 q.clear(); 071 } 072 QUEUES.clear(); 073 } 074 } 075 } 076 077 }