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: 1242 $ 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 }