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 /** 030 * Implements try/catch/finally type processing 031 * 032 * @version $Revision: 752532 $ 033 */ 034 public class TryProcessor extends ServiceSupport implements Processor { 035 private static final transient Log LOG = LogFactory.getLog(TryProcessor.class); 036 037 private final Processor tryProcessor; 038 private final List<CatchProcessor> catchClauses; 039 private final Processor finallyProcessor; 040 041 public TryProcessor(Processor tryProcessor, List<CatchProcessor> catchClauses, Processor finallyProcessor) { 042 this.tryProcessor = tryProcessor; 043 this.catchClauses = catchClauses; 044 this.finallyProcessor = finallyProcessor; 045 } 046 047 public String toString() { 048 String finallyText = (finallyProcessor == null) ? "" : " Finally {" + finallyProcessor + "}"; 049 return "Try {" + tryProcessor + "} " + catchClauses + finallyText; 050 } 051 052 public void process(Exchange exchange) throws Exception { 053 Exception e; 054 055 // try processor first 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 && ExchangeHelper.isFailureHandled(exchange)) { 062 e = null; 063 } 064 } catch (Exception ex) { 065 e = ex; 066 exchange.setException(e); 067 } 068 069 // handle any exception occured during the try processor 070 try { 071 if (e != null) { 072 if (LOG.isDebugEnabled()) { 073 LOG.debug("Caught exception while processing exchange.", e); 074 } 075 handleException(exchange, e); 076 } 077 } finally { 078 // and run finally 079 // notice its always executed since we always enter the try block 080 processFinally(exchange); 081 } 082 } 083 084 protected void doStart() throws Exception { 085 ServiceHelper.startServices(tryProcessor, catchClauses, finallyProcessor); 086 } 087 088 protected void doStop() throws Exception { 089 ServiceHelper.stopServices(tryProcessor, catchClauses, finallyProcessor); 090 } 091 092 protected void handleException(Exchange exchange, Throwable e) throws Exception { 093 for (CatchProcessor catchClause : catchClauses) { 094 if (catchClause.catches(e)) { 095 // lets attach the exception to the exchange 096 Exchange localExchange = exchange.copy(); 097 098 localExchange.setProperty(Exchange.EXCEPTION_CAUGHT, e); 099 // give the rest of the pipeline another chance 100 localExchange.setException(null); 101 102 // do not catch any exception here, let it propagate up 103 catchClause.process(localExchange); 104 localExchange.removeProperty(Exchange.EXCEPTION_CAUGHT); 105 ExchangeHelper.copyResults(exchange, localExchange); 106 return; 107 } 108 } 109 } 110 111 protected void processFinally(Exchange exchange) throws Exception { 112 if (finallyProcessor != null) { 113 Exception lastException = exchange.getException(); 114 exchange.setException(null); 115 116 // do not catch any exception here, let it propagate up 117 finallyProcessor.process(exchange); 118 if (exchange.getException() == null) { 119 exchange.setException(lastException); 120 } 121 } 122 } 123 }