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 }