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.LinkedHashMap; 020 import java.util.List; 021 import java.util.Map; 022 023 import org.apache.camel.Exchange; 024 import org.apache.camel.Processor; 025 import org.apache.camel.impl.ServiceSupport; 026 import org.apache.camel.model.OnExceptionDefinition; 027 import org.apache.camel.processor.exceptionpolicy.DefaultExceptionPolicyStrategy; 028 import org.apache.camel.processor.exceptionpolicy.ExceptionPolicyKey; 029 import org.apache.camel.processor.exceptionpolicy.ExceptionPolicyStrategy; 030 import org.apache.commons.logging.Log; 031 import org.apache.commons.logging.LogFactory; 032 033 /** 034 * Support class for {@link ErrorHandler} implementations. 035 * 036 * @version $Revision: 765920 $ 037 */ 038 public abstract class ErrorHandlerSupport extends ServiceSupport implements ErrorHandler { 039 040 protected final transient Log log = LogFactory.getLog(getClass()); 041 042 private final Map<ExceptionPolicyKey, OnExceptionDefinition> exceptionPolicies = new LinkedHashMap<ExceptionPolicyKey, OnExceptionDefinition>(); 043 private ExceptionPolicyStrategy exceptionPolicy = createDefaultExceptionPolicyStrategy(); 044 045 public void addExceptionPolicy(OnExceptionDefinition exceptionType) { 046 Processor processor = exceptionType.getErrorHandler(); 047 addChildService(processor); 048 049 List<Class> list = exceptionType.getExceptionClasses(); 050 051 for (Class clazz : list) { 052 ExceptionPolicyKey key = new ExceptionPolicyKey(clazz, exceptionType.getOnWhen()); 053 exceptionPolicies.put(key, exceptionType); 054 } 055 } 056 057 /** 058 * Attempts to invoke the handler for this particular exception if one is available 059 */ 060 protected boolean customProcessorForException(Exchange exchange, Throwable exception) throws Exception { 061 OnExceptionDefinition policy = getExceptionPolicy(exchange, exception); 062 if (policy != null) { 063 Processor processor = policy.getErrorHandler(); 064 if (processor != null) { 065 processor.process(exchange); 066 return true; 067 } 068 } 069 return false; 070 } 071 072 /** 073 * Attempts to find the best suited {@link OnExceptionDefinition} to be used for handling the given thrown exception. 074 * 075 * @param exchange the exchange 076 * @param exception the exception that was thrown 077 * @return the best exception type to handle this exception, <tt>null</tt> if none found. 078 */ 079 protected OnExceptionDefinition getExceptionPolicy(Exchange exchange, Throwable exception) { 080 if (exceptionPolicy == null) { 081 throw new IllegalStateException("The exception policy has not been set"); 082 } 083 084 return exceptionPolicy.getExceptionPolicy(exceptionPolicies, exchange, exception); 085 } 086 087 /** 088 * Sets the strategy to use for resolving the {@link OnExceptionDefinition} to use 089 * for handling thrown exceptions. 090 */ 091 public void setExceptionPolicy(ExceptionPolicyStrategy exceptionPolicy) { 092 this.exceptionPolicy = exceptionPolicy; 093 } 094 095 /** 096 * Creates the default exception policy strategy to use. 097 */ 098 public static ExceptionPolicyStrategy createDefaultExceptionPolicyStrategy() { 099 return new DefaultExceptionPolicyStrategy(); 100 } 101 102 /** 103 * Whether this error handler supports transacted exchanges or not. 104 */ 105 public abstract boolean supportTransacted(); 106 107 }