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.impl.ServiceSupport;
024 import org.apache.camel.util.ExchangeHelper;
025 import org.apache.camel.util.ServiceHelper;
026 import org.apache.commons.logging.Log;
027 import org.apache.commons.logging.LogFactory;
028
029 import static org.apache.camel.util.ObjectHelper.wrapRuntimeCamelException;
030
031 /**
032 * Implements try/catch/finally type processing
033 *
034 * @version $Revision: 695721 $
035 */
036 public class TryProcessor extends ServiceSupport implements Processor {
037 private static final transient Log LOG = LogFactory.getLog(TryProcessor.class);
038
039 private final Processor tryProcessor;
040 private final List<CatchProcessor> catchClauses;
041 private final Processor finallyProcessor;
042
043 public TryProcessor(Processor tryProcessor, List<CatchProcessor> catchClauses, Processor finallyProcessor) {
044 this.tryProcessor = tryProcessor;
045 this.catchClauses = catchClauses;
046 this.finallyProcessor = finallyProcessor;
047 }
048
049 public String toString() {
050 String finallyText = (finallyProcessor == null) ? "" : " Finally {" + finallyProcessor + "}";
051 return "Try {" + tryProcessor + "} " + catchClauses + finallyText;
052 }
053
054 public void process(Exchange exchange) throws Exception {
055 Throwable e = null;
056 try {
057 tryProcessor.process(exchange);
058 e = exchange.getException();
059
060 // Ignore it if it was handled by the dead letter channel.
061 if (e != null && DeadLetterChannel.isFailureHandled(exchange)) {
062 e = null;
063 }
064 } catch (Throwable ex) {
065 e = ex;
066 exchange.setException(e);
067 }
068
069 Exception unexpected = null;
070 try {
071 if (e != null) {
072 LOG.info("Caught exception while processing exchange.", e);
073 handleException(exchange, e);
074 }
075 } catch (Exception ex) {
076 unexpected = ex;
077 } catch (Throwable ex) {
078 unexpected = wrapRuntimeCamelException(ex);
079 } finally {
080 try {
081 processFinally(exchange);
082 } catch (Exception ex) {
083 unexpected = ex;
084 } catch (Throwable ex) {
085 unexpected = wrapRuntimeCamelException(ex);
086 }
087 if (unexpected != null) {
088 LOG.warn("Caught exception inside processFinally clause.", unexpected);
089 throw unexpected;
090 }
091 }
092
093 if (unexpected != null) {
094 LOG.warn("Caught exception inside handle clause.", unexpected);
095 throw unexpected;
096 }
097 }
098
099 protected void doStart() throws Exception {
100 ServiceHelper.startServices(tryProcessor, catchClauses, finallyProcessor);
101 }
102
103 protected void doStop() throws Exception {
104 ServiceHelper.stopServices(tryProcessor, catchClauses, finallyProcessor);
105 }
106
107 protected void handleException(Exchange exchange, Throwable e) throws Throwable {
108 for (CatchProcessor catchClause : catchClauses) {
109 if (catchClause.catches(e)) {
110 // lets attach the exception to the exchange
111 Exchange localExchange = exchange.copy();
112 localExchange.getIn().setHeader("caught.exception", e);
113 // give the rest of the pipeline another chance
114 localExchange.setException(null);
115
116 // do not catch any exception here, let it propagate up
117 catchClause.process(localExchange);
118 localExchange.getIn().removeHeader("caught.exception");
119 ExchangeHelper.copyResults(exchange, localExchange);
120 return;
121 }
122 }
123 }
124
125 protected void processFinally(Exchange exchange) throws Throwable {
126 if (finallyProcessor != null) {
127 Throwable lastException = exchange.getException();
128 exchange.setException(null);
129
130 // do not catch any exception here, let it propagate up
131 finallyProcessor.process(exchange);
132 if (exchange.getException() == null) {
133 exchange.setException(lastException);
134 }
135 }
136 }
137 }