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: 36865 $ 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; 039 040 private final List<CatchProcessor> catchClauses; 041 042 private final Processor finallyProcessor; 043 044 public TryProcessor(Processor tryProcessor, List<CatchProcessor> catchClauses, Processor finallyProcessor) { 045 this.tryProcessor = tryProcessor; 046 this.catchClauses = catchClauses; 047 this.finallyProcessor = finallyProcessor; 048 } 049 050 public String toString() { 051 String finallyText = (finallyProcessor == null) ? "" : " Finally {" + finallyProcessor + "}"; 052 return "Try {" + tryProcessor + "} " + catchClauses + finallyText; 053 } 054 055 public void process(Exchange exchange) throws Exception { 056 Throwable e = null; 057 try { 058 tryProcessor.process(exchange); 059 e = exchange.getException(); 060 061 // Ignore it if it was handled by the dead letter channel. 062 if (e != null && DeadLetterChannel.isFailureHandled(exchange)) { 063 e = null; 064 } 065 } catch (Throwable ex) { 066 e = ex; 067 exchange.setException(e); 068 } 069 070 Exception unexpected = null; 071 try { 072 if (e != null) { 073 LOG.info("Caught exception while processing exchange.", e); 074 handleException(exchange, e); 075 } 076 } catch (Exception ex) { 077 unexpected = ex; 078 } catch (Throwable ex) { 079 unexpected = new RuntimeCamelException(ex); 080 } finally { 081 try { 082 processFinally(exchange); 083 } catch (Exception ex) { 084 unexpected = ex; 085 } catch (Throwable ex) { 086 unexpected = new RuntimeCamelException(ex); 087 } 088 if (unexpected != null) { 089 LOG.warn("Caught exception inside processFinally clause.", unexpected); 090 throw unexpected; 091 } 092 } 093 094 if (unexpected != null) { 095 LOG.warn("Caught exception inside handle clause.", unexpected); 096 throw unexpected; 097 } 098 } 099 100 protected void doStart() throws Exception { 101 ServiceHelper.startServices(tryProcessor, catchClauses, finallyProcessor); 102 } 103 104 protected void doStop() throws Exception { 105 ServiceHelper.stopServices(tryProcessor, catchClauses, finallyProcessor); 106 } 107 108 protected void handleException(Exchange exchange, Throwable e) throws Throwable { 109 for (CatchProcessor catchClause : catchClauses) { 110 if (catchClause.catches(e)) { 111 // lets attach the exception to the exchange 112 Exchange localExchange = exchange.copy(); 113 localExchange.getIn().setHeader("caught.exception", e); 114 // give the rest of the pipeline another chance 115 localExchange.setException(null); 116 117 // do not catch any exception here, let it propagate up 118 catchClause.process(localExchange); 119 localExchange.getIn().removeHeader("caught.exception"); 120 ExchangeHelper.copyResults(exchange, localExchange); 121 return; 122 } 123 } 124 } 125 126 protected void processFinally(Exchange exchange) throws Throwable { 127 if (finallyProcessor != null) { 128 Throwable lastException = exchange.getException(); 129 exchange.setException(null); 130 131 // do not catch any exception here, let it propagate up 132 finallyProcessor.process(exchange); 133 if (exchange.getException() == null) { 134 exchange.setException(lastException); 135 } 136 } 137 } 138 }