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 */ 017package org.apache.camel.processor.loadbalancer; 018 019import java.util.List; 020 021import org.apache.camel.AsyncCallback; 022import org.apache.camel.Exchange; 023import org.apache.camel.Processor; 024 025/** 026 * A {@link LoadBalancer} implementations which sends to all destinations 027 * (rather like JMS Topics). 028 * <p/> 029 * The {@link org.apache.camel.processor.MulticastProcessor} is more powerful as it offers 030 * option to run in parallel and decide whether or not to stop on failure etc. 031 * 032 * @version 033 */ 034public class TopicLoadBalancer extends LoadBalancerSupport { 035 036 public boolean process(final Exchange exchange, final AsyncCallback callback) { 037 List<Processor> list = getProcessors(); 038 // too hard to do multiple async, so we do it sync 039 for (Processor processor : list) { 040 try { 041 Exchange copy = copyExchangeStrategy(processor, exchange); 042 processor.process(copy); 043 } catch (Throwable e) { 044 exchange.setException(e); 045 // stop on failure 046 break; 047 } 048 } 049 callback.done(true); 050 return true; 051 } 052 053 /** 054 * Strategy method to copy the exchange before sending to another endpoint. 055 * Derived classes such as the {@link org.apache.camel.processor.Pipeline Pipeline} 056 * will not clone the exchange 057 * 058 * @param processor the processor that will send the exchange 059 * @param exchange the exchange 060 * @return the current exchange if no copying is required such as for a 061 * pipeline otherwise a new copy of the exchange is returned. 062 */ 063 protected Exchange copyExchangeStrategy(Processor processor, Exchange exchange) { 064 return exchange.copy(); 065 } 066 067 public String toString() { 068 return "TopicLoadBalancer"; 069 } 070}