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.ServiceHelper;
025 import org.apache.commons.logging.Log;
026 import org.apache.commons.logging.LogFactory;
027
028 /**
029 * Implements try/catch/finally type processing
030 *
031 * @version $Revision: $
032 */
033 public class TryProcessor extends ServiceSupport implements Processor {
034 private static final Log LOG = LogFactory.getLog(TryProcessor.class);
035
036 private final Processor tryProcessor;
037 private final List<CatchProcessor> catchClauses;
038 private final Processor finallyProcessor;
039
040 public TryProcessor(Processor tryProcessor, List<CatchProcessor> catchClauses, Processor finallyProcessor) {
041 this.tryProcessor = tryProcessor;
042 this.catchClauses = catchClauses;
043 this.finallyProcessor = finallyProcessor;
044 }
045
046 public String toString() {
047 String finallyText = (finallyProcessor == null) ? "" : " Finally {" + finallyProcessor + "}";
048 return "Try {" + tryProcessor + "} " + catchClauses + finallyText;
049 }
050
051 public void process(Exchange exchange) throws Exception {
052 boolean doneTry = false;
053 try {
054 tryProcessor.process(exchange);
055 doneTry = true;
056
057 if (finallyProcessor != null) {
058 finallyProcessor.process(exchange);
059 }
060 } catch (Exception e) {
061 handleException(exchange, e);
062
063 if (!doneTry && finallyProcessor != null) {
064 try {
065 finallyProcessor.process(exchange);
066 } catch (Exception e2) {
067 LOG.warn("Caught exception in finally block while handling other exception: " + e2, e2);
068 }
069 }
070 }
071 }
072
073 protected void doStart() throws Exception {
074 ServiceHelper.startServices(tryProcessor, catchClauses, finallyProcessor);
075 }
076
077 protected void doStop() throws Exception {
078 ServiceHelper.stopServices(tryProcessor, catchClauses, finallyProcessor);
079 }
080
081 protected void handleException(Exchange exchange, Exception e) throws Exception {
082 for (CatchProcessor catchClause : catchClauses) {
083 if (catchClause.catches(e)) {
084 // lets attach the exception to the exchange
085 exchange.setException(e);
086 try {
087 catchClause.process(exchange);
088 } catch (Exception e1) {
089 LOG.warn("Caught exception inside catch clause: " + e1, e1);
090 throw e1;
091 }
092 return;
093 }
094 }
095
096 // unhandled exception
097 throw e;
098 }
099 }