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.processor; 018 019 import java.util.ArrayList; 020 import java.util.List; 021 022 import org.apache.camel.Channel; 023 import org.apache.camel.Exchange; 024 import org.apache.camel.Processor; 025 import org.apache.camel.impl.ServiceSupport; 026 import org.apache.camel.model.ProcessorDefinition; 027 import org.apache.camel.spi.InterceptStrategy; 028 import org.apache.camel.spi.RouteContext; 029 import org.apache.camel.util.ServiceHelper; 030 import org.apache.commons.logging.Log; 031 import org.apache.commons.logging.LogFactory; 032 033 /** 034 * DefaultChannel is the default {@link Channel}. 035 * <p/> 036 * The current implementation is just a composite containing the interceptors and error handler 037 * that beforehand was added to the route graph directly. 038 * <br/> 039 * With this {@link Channel} we can in the future implement better strategies for routing the 040 * {@link Exchange} in the route graph, as we have a {@link Channel} between each and every node 041 * in the graph. 042 * 043 * @version $Revision: 771248 $ 044 */ 045 public class DefaultChannel extends ServiceSupport implements Processor, Channel { 046 047 private static final transient Log LOG = LogFactory.getLog(DefaultChannel.class); 048 049 private final List<InterceptStrategy> interceptors = new ArrayList<InterceptStrategy>(); 050 private Processor errorHandler; 051 // the next processor (non wrapped) 052 private Processor nextProcessor; 053 // the real output to invoke that has been wrapped 054 private Processor output; 055 private ProcessorDefinition definition; 056 057 public List<Processor> next() { 058 List<Processor> answer = new ArrayList<Processor>(1); 059 answer.add(nextProcessor); 060 return answer; 061 } 062 063 public boolean hasNext() { 064 return nextProcessor != null; 065 } 066 067 public void setNextProcessor(Processor next) { 068 this.nextProcessor = next; 069 } 070 071 public Processor getOutput() { 072 // the errorHandler is already decorated with interceptors 073 // so it cointain the entire chain of processors, so we can safely use it directly as output 074 // if no error handler provided we can use the output direcly 075 return errorHandler != null ? errorHandler : output; 076 } 077 078 public void setOutput(Processor output) { 079 this.output = output; 080 } 081 082 public Processor getNextProcessor() { 083 return nextProcessor; 084 } 085 086 public boolean hasInterceptorStrategy(Class type) { 087 for (InterceptStrategy strategy : interceptors) { 088 if (type.isInstance(strategy)) { 089 return true; 090 } 091 } 092 return false; 093 } 094 095 public void setErrorHandler(Processor errorHandler) { 096 this.errorHandler = errorHandler; 097 } 098 099 public Processor getErrorHandler() { 100 return errorHandler; 101 } 102 103 public void addInterceptStrategy(InterceptStrategy strategy) { 104 interceptors.add(strategy); 105 } 106 107 public void addInterceptStrategies(List<InterceptStrategy> strategies) { 108 interceptors.addAll(strategies); 109 } 110 111 public List<InterceptStrategy> getInterceptStrategies() { 112 return interceptors; 113 } 114 115 public ProcessorDefinition getProcessorDefinition() { 116 return definition; 117 } 118 119 @Override 120 protected void doStart() throws Exception { 121 ServiceHelper.startServices(errorHandler, output); 122 } 123 124 @Override 125 protected void doStop() throws Exception { 126 ServiceHelper.stopServices(output, errorHandler); 127 } 128 129 public void initChannel(ProcessorDefinition outputDefinition, RouteContext routeContext) throws Exception { 130 this.definition = outputDefinition; 131 132 // TODO: Support ordering of interceptors 133 134 // wrap the output with the interceptors 135 Processor target = nextProcessor; 136 for (InterceptStrategy strategy : interceptors) { 137 target = strategy.wrapProcessorInInterceptors(outputDefinition, target, nextProcessor); 138 } 139 140 // sets the delegate to our wrapped output 141 output = target; 142 } 143 144 public void process(Exchange exchange) throws Exception { 145 Processor processor = getOutput(); 146 if (processor != null && continueProcessing(exchange)) { 147 processor.process(exchange); 148 } 149 } 150 151 /** 152 * Strategy to determine if we should continue processing the {@link Exchange}. 153 */ 154 protected boolean continueProcessing(Exchange exchange) { 155 Object stop = exchange.getProperty(Exchange.ROUTE_STOP); 156 if (stop != null) { 157 boolean doStop = exchange.getContext().getTypeConverter().convertTo(Boolean.class, stop); 158 if (doStop) { 159 if (LOG.isDebugEnabled()) { 160 LOG.debug("Exchange is marked to stop routing: " + exchange); 161 } 162 return false; 163 } 164 } 165 return true; 166 } 167 168 @Override 169 public String toString() { 170 // just output the next processor as all the interceptors and error handler is just too verbose 171 return "Channel[" + nextProcessor + "]"; 172 } 173 174 }