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.component.seda.SedaComponent; 025 026 /** 027 * An implementation of the <a href="http://camel.apache.org/vm.html">VM components</a> 028 * for asynchronous SEDA exchanges on a {@link BlockingQueue} within the classloader tree containing 029 * the camel-core.jar. i.e. to handle communicating across CamelContext instances and possibly across 030 * web application contexts, providing that camel-core.jar is on the system classpath. 031 * 032 * @version 033 */ 034 public class VmComponent extends SedaComponent { 035 protected static final Map<String, QueueReference> QUEUES = new HashMap<String, QueueReference>(); 036 private static final AtomicInteger START_COUNTER = new AtomicInteger(); 037 038 @Override 039 public Map<String, QueueReference> getQueues() { 040 return QUEUES; 041 } 042 043 @Override 044 protected void doStart() throws Exception { 045 super.doStart(); 046 START_COUNTER.incrementAndGet(); 047 } 048 049 @Override 050 protected void doStop() throws Exception { 051 if (START_COUNTER.decrementAndGet() <= 0) { 052 // clear queues when no more vm components in use 053 getQueues().clear(); 054 } 055 } 056 }