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.ArrayList; 020import java.util.Collection; 021import java.util.Iterator; 022import java.util.List; 023 024import org.apache.camel.AsyncCallback; 025import org.apache.camel.AsyncProcessor; 026import org.apache.camel.CamelContext; 027import org.apache.camel.Exchange; 028import org.apache.camel.Processor; 029import org.apache.camel.util.AsyncProcessorConverterHelper; 030import org.apache.camel.util.AsyncProcessorHelper; 031import org.apache.camel.util.ExchangeHelper; 032import org.slf4j.Logger; 033import org.slf4j.LoggerFactory; 034 035import static org.apache.camel.processor.PipelineHelper.continueProcessing; 036 037/** 038 * Creates a Pipeline pattern where the output of the previous step is sent as 039 * input to the next step, reusing the same message exchanges 040 * 041 * @version 042 */ 043public class Pipeline extends MulticastProcessor { 044 private static final Logger LOG = LoggerFactory.getLogger(Pipeline.class); 045 046 private String id; 047 048 public Pipeline(CamelContext camelContext, Collection<Processor> processors) { 049 super(camelContext, processors); 050 } 051 052 public static Processor newInstance(CamelContext camelContext, List<Processor> processors) { 053 if (processors.isEmpty()) { 054 return null; 055 } else if (processors.size() == 1) { 056 return processors.get(0); 057 } 058 return new Pipeline(camelContext, processors); 059 } 060 061 public static Processor newInstance(final CamelContext camelContext, final Processor... processors) { 062 if (processors == null || processors.length == 0) { 063 return null; 064 } else if (processors.length == 1) { 065 return processors[0]; 066 } 067 068 final List<Processor> toBeProcessed = new ArrayList<>(processors.length); 069 for (Processor processor : processors) { 070 if (processor != null) { 071 toBeProcessed.add(processor); 072 } 073 } 074 075 return new Pipeline(camelContext, toBeProcessed); 076 } 077 078 @Override 079 public void process(Exchange exchange) throws Exception { 080 AsyncProcessorHelper.process(this, exchange); 081 } 082 083 @Override 084 public boolean process(Exchange exchange, AsyncCallback callback) { 085 Iterator<Processor> processors = getProcessors().iterator(); 086 Exchange nextExchange = exchange; 087 boolean first = true; 088 089 while (continueRouting(processors, nextExchange)) { 090 if (first) { 091 first = false; 092 } else { 093 // prepare for next run 094 nextExchange = createNextExchange(nextExchange); 095 } 096 097 // get the next processor 098 Processor processor = processors.next(); 099 100 AsyncProcessor async = AsyncProcessorConverterHelper.convert(processor); 101 boolean sync = process(exchange, nextExchange, callback, processors, async); 102 103 // continue as long its being processed synchronously 104 if (!sync) { 105 LOG.trace("Processing exchangeId: {} is continued being processed asynchronously", exchange.getExchangeId()); 106 // the remainder of the pipeline will be completed async 107 // so we break out now, then the callback will be invoked which then continue routing from where we left here 108 return false; 109 } 110 111 LOG.trace("Processing exchangeId: {} is continued being processed synchronously", exchange.getExchangeId()); 112 113 // check for error if so we should break out 114 if (!continueProcessing(nextExchange, "so breaking out of pipeline", LOG)) { 115 break; 116 } 117 } 118 119 // logging nextExchange as it contains the exchange that might have altered the payload and since 120 // we are logging the completion if will be confusing if we log the original instead 121 // we could also consider logging the original and the nextExchange then we have *before* and *after* snapshots 122 LOG.trace("Processing complete for exchangeId: {} >>> {}", exchange.getExchangeId(), nextExchange); 123 124 // copy results back to the original exchange 125 ExchangeHelper.copyResults(exchange, nextExchange); 126 127 callback.done(true); 128 return true; 129 } 130 131 private boolean process(final Exchange original, final Exchange exchange, final AsyncCallback callback, 132 final Iterator<Processor> processors, final AsyncProcessor asyncProcessor) { 133 // this does the actual processing so log at trace level 134 LOG.trace("Processing exchangeId: {} >>> {}", exchange.getExchangeId(), exchange); 135 136 // implement asynchronous routing logic in callback so we can have the callback being 137 // triggered and then continue routing where we left 138 boolean sync = asyncProcessor.process(exchange, new AsyncCallback() { 139 @Override 140 public void done(final boolean doneSync) { 141 // we only have to handle async completion of the pipeline 142 if (doneSync) { 143 return; 144 } 145 146 // continue processing the pipeline asynchronously 147 Exchange nextExchange = exchange; 148 while (continueRouting(processors, nextExchange)) { 149 AsyncProcessor processor = AsyncProcessorConverterHelper.convert(processors.next()); 150 151 // check for error if so we should break out 152 if (!continueProcessing(nextExchange, "so breaking out of pipeline", LOG)) { 153 break; 154 } 155 156 nextExchange = createNextExchange(nextExchange); 157 boolean isDoneSync = process(original, nextExchange, callback, processors, processor); 158 if (!isDoneSync) { 159 LOG.trace("Processing exchangeId: {} is continued being processed asynchronously", exchange.getExchangeId()); 160 return; 161 } 162 } 163 164 ExchangeHelper.copyResults(original, nextExchange); 165 LOG.trace("Processing complete for exchangeId: {} >>> {}", original.getExchangeId(), original); 166 callback.done(false); 167 } 168 }); 169 170 return sync; 171 } 172 173 /** 174 * Strategy method to create the next exchange from the previous exchange. 175 * <p/> 176 * Remember to copy the original exchange id otherwise correlation of ids in the log is a problem 177 * 178 * @param previousExchange the previous exchange 179 * @return a new exchange 180 */ 181 protected Exchange createNextExchange(Exchange previousExchange) { 182 return PipelineHelper.createNextExchange(previousExchange); 183 } 184 185 protected boolean continueRouting(Iterator<Processor> it, Exchange exchange) { 186 boolean answer = true; 187 188 Object stop = exchange.getProperty(Exchange.ROUTE_STOP); 189 if (stop != null) { 190 boolean doStop = exchange.getContext().getTypeConverter().convertTo(Boolean.class, stop); 191 if (doStop) { 192 LOG.debug("ExchangeId: {} is marked to stop routing: {}", exchange.getExchangeId(), exchange); 193 answer = false; 194 } 195 } else { 196 // continue if there are more processors to route 197 answer = it.hasNext(); 198 } 199 200 LOG.trace("ExchangeId: {} should continue routing: {}", exchange.getExchangeId(), answer); 201 return answer; 202 } 203 204 @Override 205 public String toString() { 206 return "Pipeline[" + getProcessors() + "]"; 207 } 208 209 @Override 210 public String getTraceLabel() { 211 return "pipeline"; 212 } 213 214 @Override 215 public String getId() { 216 return id; 217 } 218 219 @Override 220 public void setId(String id) { 221 this.id = id; 222 } 223}