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; 018 019import java.util.Collection; 020import java.util.Iterator; 021import java.util.List; 022 023import org.apache.camel.AsyncCallback; 024import org.apache.camel.AsyncProcessor; 025import org.apache.camel.CamelContext; 026import org.apache.camel.Exchange; 027import org.apache.camel.Processor; 028import org.apache.camel.Traceable; 029import org.apache.camel.spi.IdAware; 030import org.apache.camel.util.AsyncProcessorConverterHelper; 031import org.apache.camel.util.AsyncProcessorHelper; 032import org.apache.camel.util.ExchangeHelper; 033import org.slf4j.Logger; 034import org.slf4j.LoggerFactory; 035 036import static org.apache.camel.processor.PipelineHelper.continueProcessing; 037 038/** 039 * Creates a Pipeline pattern where the output of the previous step is sent as 040 * input to the next step, reusing the same message exchanges 041 * 042 * @version 043 */ 044public class Pipeline extends MulticastProcessor implements AsyncProcessor, Traceable, IdAware { 045 private static final Logger LOG = LoggerFactory.getLogger(Pipeline.class); 046 047 private String id; 048 049 public Pipeline(CamelContext camelContext, Collection<Processor> processors) { 050 super(camelContext, processors); 051 } 052 053 public static Processor newInstance(CamelContext camelContext, List<Processor> processors) { 054 if (processors.isEmpty()) { 055 return null; 056 } else if (processors.size() == 1) { 057 return processors.get(0); 058 } 059 return new Pipeline(camelContext, processors); 060 } 061 062 public void process(Exchange exchange) throws Exception { 063 AsyncProcessorHelper.process(this, exchange); 064 } 065 066 public boolean process(Exchange exchange, AsyncCallback callback) { 067 Iterator<Processor> processors = getProcessors().iterator(); 068 Exchange nextExchange = exchange; 069 boolean first = true; 070 071 while (continueRouting(processors, nextExchange)) { 072 if (first) { 073 first = false; 074 } else { 075 // prepare for next run 076 nextExchange = createNextExchange(nextExchange); 077 } 078 079 // get the next processor 080 Processor processor = processors.next(); 081 082 AsyncProcessor async = AsyncProcessorConverterHelper.convert(processor); 083 boolean sync = process(exchange, nextExchange, callback, processors, async); 084 085 // continue as long its being processed synchronously 086 if (!sync) { 087 LOG.trace("Processing exchangeId: {} is continued being processed asynchronously", exchange.getExchangeId()); 088 // the remainder of the pipeline will be completed async 089 // so we break out now, then the callback will be invoked which then continue routing from where we left here 090 return false; 091 } 092 093 LOG.trace("Processing exchangeId: {} is continued being processed synchronously", exchange.getExchangeId()); 094 095 // check for error if so we should break out 096 if (!continueProcessing(nextExchange, "so breaking out of pipeline", LOG)) { 097 break; 098 } 099 } 100 101 // logging nextExchange as it contains the exchange that might have altered the payload and since 102 // we are logging the completion if will be confusing if we log the original instead 103 // we could also consider logging the original and the nextExchange then we have *before* and *after* snapshots 104 LOG.trace("Processing complete for exchangeId: {} >>> {}", exchange.getExchangeId(), nextExchange); 105 106 // copy results back to the original exchange 107 ExchangeHelper.copyResults(exchange, nextExchange); 108 109 callback.done(true); 110 return true; 111 } 112 113 private boolean process(final Exchange original, final Exchange exchange, final AsyncCallback callback, 114 final Iterator<Processor> processors, final AsyncProcessor asyncProcessor) { 115 // this does the actual processing so log at trace level 116 LOG.trace("Processing exchangeId: {} >>> {}", exchange.getExchangeId(), exchange); 117 118 // implement asynchronous routing logic in callback so we can have the callback being 119 // triggered and then continue routing where we left 120 boolean sync = asyncProcessor.process(exchange, new AsyncCallback() { 121 public void done(boolean doneSync) { 122 // we only have to handle async completion of the pipeline 123 if (doneSync) { 124 return; 125 } 126 127 // continue processing the pipeline asynchronously 128 Exchange nextExchange = exchange; 129 while (continueRouting(processors, nextExchange)) { 130 AsyncProcessor processor = AsyncProcessorConverterHelper.convert(processors.next()); 131 132 // check for error if so we should break out 133 if (!continueProcessing(nextExchange, "so breaking out of pipeline", LOG)) { 134 break; 135 } 136 137 nextExchange = createNextExchange(nextExchange); 138 doneSync = process(original, nextExchange, callback, processors, processor); 139 if (!doneSync) { 140 LOG.trace("Processing exchangeId: {} is continued being processed asynchronously", exchange.getExchangeId()); 141 return; 142 } 143 } 144 145 ExchangeHelper.copyResults(original, nextExchange); 146 LOG.trace("Processing complete for exchangeId: {} >>> {}", original.getExchangeId(), original); 147 callback.done(false); 148 } 149 }); 150 151 return sync; 152 } 153 154 /** 155 * Strategy method to create the next exchange from the previous exchange. 156 * <p/> 157 * Remember to copy the original exchange id otherwise correlation of ids in the log is a problem 158 * 159 * @param previousExchange the previous exchange 160 * @return a new exchange 161 */ 162 protected Exchange createNextExchange(Exchange previousExchange) { 163 return PipelineHelper.createNextExchange(previousExchange); 164 } 165 166 protected boolean continueRouting(Iterator<Processor> it, Exchange exchange) { 167 boolean answer = true; 168 169 Object stop = exchange.getProperty(Exchange.ROUTE_STOP); 170 if (stop != null) { 171 boolean doStop = exchange.getContext().getTypeConverter().convertTo(Boolean.class, stop); 172 if (doStop) { 173 LOG.debug("ExchangeId: {} is marked to stop routing: {}", exchange.getExchangeId(), exchange); 174 answer = false; 175 } 176 } else { 177 // continue if there are more processors to route 178 answer = it.hasNext(); 179 } 180 181 LOG.trace("ExchangeId: {} should continue routing: {}", exchange.getExchangeId(), answer); 182 return answer; 183 } 184 185 @Override 186 public String toString() { 187 return "Pipeline[" + getProcessors() + "]"; 188 } 189 190 @Override 191 public String getTraceLabel() { 192 return "pipeline"; 193 } 194 195 public String getId() { 196 return id; 197 } 198 199 public void setId(String id) { 200 this.id = id; 201 } 202}