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: 41910 $ 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 }