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.Collection; 021 import java.util.List; 022 import java.util.concurrent.Callable; 023 import java.util.concurrent.CompletionService; 024 import java.util.concurrent.ExecutionException; 025 import java.util.concurrent.ExecutorCompletionService; 026 import java.util.concurrent.ExecutorService; 027 import java.util.concurrent.Future; 028 import java.util.concurrent.TimeUnit; 029 030 import org.apache.camel.Exchange; 031 import org.apache.camel.Navigate; 032 import org.apache.camel.Processor; 033 import org.apache.camel.impl.ServiceSupport; 034 import org.apache.camel.processor.aggregate.AggregationStrategy; 035 import org.apache.camel.util.ExchangeHelper; 036 import org.apache.camel.util.ServiceHelper; 037 import org.apache.camel.util.concurrent.AtomicExchange; 038 import org.apache.camel.util.concurrent.ExecutorServiceHelper; 039 import org.apache.camel.util.concurrent.SubmitOrderedCompletionService; 040 import org.apache.commons.logging.Log; 041 import org.apache.commons.logging.LogFactory; 042 043 import static org.apache.camel.util.ObjectHelper.notNull; 044 045 /** 046 * Implements the Multicast pattern to send a message exchange to a number of 047 * endpoints, each endpoint receiving a copy of the message exchange. 048 * 049 * @see Pipeline 050 * @version $Revision: 783663 $ 051 */ 052 public class MulticastProcessor extends ServiceSupport implements Processor, Navigate { 053 054 private static final transient Log LOG = LogFactory.getLog(MulticastProcessor.class); 055 056 // TODO: Add option to stop if an exception was thrown during processing to break asap (future task cancel) 057 058 /** 059 * Class that represent each step in the multicast route to do 060 */ 061 static class ProcessorExchangePair { 062 private final Processor processor; 063 private final Exchange exchange; 064 065 public ProcessorExchangePair(Processor processor, Exchange exchange) { 066 this.processor = processor; 067 this.exchange = exchange; 068 } 069 070 public Processor getProcessor() { 071 return processor; 072 } 073 074 public Exchange getExchange() { 075 return exchange; 076 } 077 } 078 079 private final Collection<Processor> processors; 080 private final AggregationStrategy aggregationStrategy; 081 private final boolean isParallelProcessing; 082 private final boolean streaming; 083 private ExecutorService executorService; 084 085 public MulticastProcessor(Collection<Processor> processors) { 086 this(processors, null); 087 } 088 089 public MulticastProcessor(Collection<Processor> processors, AggregationStrategy aggregationStrategy) { 090 this(processors, aggregationStrategy, false, null, false); 091 } 092 093 public MulticastProcessor(Collection<Processor> processors, AggregationStrategy aggregationStrategy, boolean parallelProcessing, ExecutorService executorService, boolean streaming) { 094 notNull(processors, "processors"); 095 // TODO: end() does not work correctly with Splitter 096 this.processors = processors; 097 this.aggregationStrategy = aggregationStrategy; 098 this.isParallelProcessing = parallelProcessing; 099 this.executorService = executorService; 100 this.streaming = streaming; 101 102 if (isParallelProcessing()) { 103 if (this.executorService == null) { 104 // setup default executor as parallel processing requires an executor 105 this.executorService = ExecutorServiceHelper.newScheduledThreadPool(5, "Multicast", true); 106 } 107 } 108 } 109 110 @Override 111 public String toString() { 112 return "Multicast[" + getProcessors() + "]"; 113 } 114 115 public void process(Exchange exchange) throws Exception { 116 final AtomicExchange result = new AtomicExchange(); 117 final Iterable<ProcessorExchangePair> pairs = createProcessorExchangePairs(exchange); 118 119 if (isParallelProcessing()) { 120 doProcessParallel(result, pairs, isStreaming()); 121 } else { 122 doProcessSequntiel(result, pairs); 123 } 124 125 if (result.get() != null) { 126 ExchangeHelper.copyResults(exchange, result.get()); 127 } 128 } 129 130 protected void doProcessParallel(final AtomicExchange result, Iterable<ProcessorExchangePair> pairs, boolean streaming) throws InterruptedException, ExecutionException { 131 CompletionService<Exchange> completion; 132 if (streaming) { 133 // execute tasks in paralle+streaming and aggregate in the order they are finished (out of order sequence) 134 completion = new ExecutorCompletionService<Exchange>(executorService); 135 } else { 136 // execute tasks in parallel and aggregate in the order the tasks are submitted (in order sequence) 137 completion = new SubmitOrderedCompletionService<Exchange>(executorService); 138 } 139 int total = 0; 140 141 for (ProcessorExchangePair pair : pairs) { 142 final Processor producer = pair.getProcessor(); 143 final Exchange subExchange = pair.getExchange(); 144 updateNewExchange(subExchange, total, pairs); 145 146 completion.submit(new Callable<Exchange>() { 147 public Exchange call() throws Exception { 148 try { 149 producer.process(subExchange); 150 } catch (Exception e) { 151 subExchange.setException(e); 152 } 153 if (LOG.isTraceEnabled()) { 154 LOG.trace("Parallel processing complete for exchange: " + subExchange); 155 } 156 return subExchange; 157 } 158 }); 159 160 total++; 161 } 162 163 for (int i = 0; i < total; i++) { 164 Future<Exchange> future = completion.take(); 165 Exchange subExchange = future.get(); 166 if (aggregationStrategy != null) { 167 doAggregate(result, subExchange); 168 } 169 } 170 171 if (LOG.isDebugEnabled()) { 172 LOG.debug("Done parallel processing " + total + " exchanges"); 173 } 174 } 175 176 protected void doProcessSequntiel(AtomicExchange result, Iterable<ProcessorExchangePair> pairs) throws Exception { 177 int total = 0; 178 179 for (ProcessorExchangePair pair : pairs) { 180 Processor producer = pair.getProcessor(); 181 Exchange subExchange = pair.getExchange(); 182 updateNewExchange(subExchange, total, pairs); 183 184 // process it sequentially 185 producer.process(subExchange); 186 if (LOG.isTraceEnabled()) { 187 LOG.trace("Sequientel processing complete for number " + total + " exchange: " + subExchange); 188 } 189 190 if (aggregationStrategy != null) { 191 doAggregate(result, subExchange); 192 } 193 total++; 194 } 195 196 if (LOG.isDebugEnabled()) { 197 LOG.debug("Done sequientel processing " + total + " exchanges"); 198 } 199 } 200 201 /** 202 * Aggregate the {@link Exchange} with the current result 203 * 204 * @param result the current result 205 * @param exchange the exchange to be added to the result 206 */ 207 protected synchronized void doAggregate(AtomicExchange result, Exchange exchange) { 208 // only aggregate if the exchange is not filtered (eg by the FilterProcessor) 209 Boolean filtered = exchange.getProperty(Exchange.FILTERED, Boolean.class); 210 if (aggregationStrategy != null && (filtered == null || !filtered)) { 211 result.set(aggregationStrategy.aggregate(result.get(), exchange)); 212 } else { 213 if (LOG.isTraceEnabled()) { 214 LOG.trace("Cannot aggregate exchange as its filtered: " + exchange); 215 } 216 } 217 } 218 219 protected void updateNewExchange(Exchange exchange, int index, Iterable<ProcessorExchangePair> allPairs) { 220 exchange.getIn().setHeader(Exchange.MULTICAST_INDEX, index); 221 } 222 223 protected Iterable<ProcessorExchangePair> createProcessorExchangePairs(Exchange exchange) { 224 List<ProcessorExchangePair> result = new ArrayList<ProcessorExchangePair>(processors.size()); 225 226 for (Processor processor : processors) { 227 Exchange copy = exchange.copy(); 228 result.add(new ProcessorExchangePair(processor, copy)); 229 } 230 return result; 231 } 232 233 protected void doStop() throws Exception { 234 if (executorService != null) { 235 executorService.shutdown(); 236 executorService.awaitTermination(0, TimeUnit.SECONDS); 237 } 238 ServiceHelper.stopServices(processors); 239 } 240 241 protected void doStart() throws Exception { 242 ServiceHelper.startServices(processors); 243 } 244 245 /** 246 * Is the multicast processor working in streaming mode? 247 * 248 * In streaming mode: 249 * <ul> 250 * <li>we use {@link Iterable} to ensure we can send messages as soon as the data becomes available</li> 251 * <li>for parallel processing, we start aggregating responses as they get send back to the processor; 252 * this means the {@link org.apache.camel.processor.aggregate.AggregationStrategy} has to take care of handling out-of-order arrival of exchanges</li> 253 * </ul> 254 */ 255 public boolean isStreaming() { 256 return streaming; 257 } 258 259 /** 260 * Returns the producers to multicast to 261 */ 262 public Collection<Processor> getProcessors() { 263 return processors; 264 } 265 266 public AggregationStrategy getAggregationStrategy() { 267 return aggregationStrategy; 268 } 269 270 public boolean isParallelProcessing() { 271 return isParallelProcessing; 272 } 273 274 public ExecutorService getExecutorService() { 275 return executorService; 276 } 277 278 public void setExecutorService(ExecutorService executorService) { 279 this.executorService = executorService; 280 } 281 282 public List<Processor> next() { 283 if (!hasNext()) { 284 return null; 285 } 286 return new ArrayList<Processor>(processors); 287 } 288 289 public boolean hasNext() { 290 return processors != null && !processors.isEmpty(); 291 } 292 }