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.List;
020
021 import org.apache.camel.Exchange;
022 import org.apache.camel.Processor;
023 import org.apache.camel.RuntimeCamelException;
024 import org.apache.camel.impl.ServiceSupport;
025 import org.apache.camel.util.ExchangeHelper;
026 import org.apache.camel.util.ServiceHelper;
027 import org.apache.commons.logging.Log;
028 import org.apache.commons.logging.LogFactory;
029
030 /**
031 * Implements try/catch/finally type processing
032 *
033 * @version $Revision: 660275 $
034 */
035 public class TryProcessor extends ServiceSupport implements Processor {
036 private static final transient Log LOG = LogFactory.getLog(TryProcessor.class);
037
038 private final Processor tryProcessor;
039 private final List<CatchProcessor> catchClauses;
040 private final Processor finallyProcessor;
041
042 public TryProcessor(Processor tryProcessor, List<CatchProcessor> catchClauses, Processor finallyProcessor) {
043 this.tryProcessor = tryProcessor;
044 this.catchClauses = catchClauses;
045 this.finallyProcessor = finallyProcessor;
046 }
047
048 public String toString() {
049 String finallyText = (finallyProcessor == null) ? "" : " Finally {" + finallyProcessor + "}";
050 return "Try {" + tryProcessor + "} " + catchClauses + finallyText;
051 }
052
053 public void process(Exchange exchange) throws Exception {
054 Throwable e = null;
055 try {
056 tryProcessor.process(exchange);
057 e = exchange.getException();
058
059 // Ignore it if it was handled by the dead letter channel.
060 if (e != null && DeadLetterChannel.isFailureHandled(exchange)) {
061 e = null;
062 }
063 } catch (Throwable ex) {
064 e = ex;
065 exchange.setException(e);
066 }
067
068 Exception unexpected = null;
069 try {
070 if (e != null) {
071 LOG.info("Caught exception while processing exchange.", e);
072 handleException(exchange, e);
073 }
074 } catch (Exception ex) {
075 unexpected = ex;
076 } catch (Throwable ex) {
077 unexpected = new RuntimeCamelException(ex);
078 } finally {
079 try {
080 processFinally(exchange);
081 } catch (Exception ex) {
082 unexpected = ex;
083 } catch (Throwable ex) {
084 unexpected = new RuntimeCamelException(ex);
085 }
086 if (unexpected != null) {
087 LOG.warn("Caught exception inside processFinally clause.", unexpected);
088 throw unexpected;
089 }
090 }
091
092 if (unexpected != null) {
093 LOG.warn("Caught exception inside handle clause.", unexpected);
094 throw unexpected;
095 }
096 }
097
098 protected void doStart() throws Exception {
099 ServiceHelper.startServices(tryProcessor, catchClauses, finallyProcessor);
100 }
101
102 protected void doStop() throws Exception {
103 ServiceHelper.stopServices(tryProcessor, catchClauses, finallyProcessor);
104 }
105
106 protected void handleException(Exchange exchange, Throwable e) throws Throwable {
107 for (CatchProcessor catchClause : catchClauses) {
108 if (catchClause.catches(e)) {
109 // lets attach the exception to the exchange
110 Exchange localExchange = exchange.copy();
111 localExchange.getIn().setHeader("caught.exception", e);
112 // give the rest of the pipeline another chance
113 localExchange.setException(null);
114
115 // do not catch any exception here, let it propagate up
116 catchClause.process(localExchange);
117 localExchange.getIn().removeHeader("caught.exception");
118 ExchangeHelper.copyResults(exchange, localExchange);
119 return;
120 }
121 }
122 }
123
124 protected void processFinally(Exchange exchange) throws Throwable {
125 if (finallyProcessor != null) {
126 Throwable lastException = exchange.getException();
127 exchange.setException(null);
128
129 // do not catch any exception here, let it propagate up
130 finallyProcessor.process(exchange);
131 if (exchange.getException() == null) {
132 exchange.setException(lastException);
133 }
134 }
135 }
136 }