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.ExceptionType; 027 import org.apache.camel.processor.exceptionpolicy.DefaultExceptionPolicyStrategy; 028 import org.apache.camel.processor.exceptionpolicy.ExceptionPolicyKey; 029 import org.apache.camel.processor.exceptionpolicy.ExceptionPolicyStrategy; 030 031 /** 032 * Support class for {@link ErrorHandler} implementations. 033 * 034 * @version $Revision: 1767 $ 035 */ 036 public abstract class ErrorHandlerSupport extends ServiceSupport implements ErrorHandler { 037 private Map<ExceptionPolicyKey, ExceptionType> exceptionPolicies = new LinkedHashMap<ExceptionPolicyKey, ExceptionType>(); 038 private ExceptionPolicyStrategy exceptionPolicy = createDefaultExceptionPolicyStrategy(); 039 040 public void addExceptionPolicy(ExceptionType exceptionType) { 041 Processor processor = exceptionType.getErrorHandler(); 042 addChildService(processor); 043 044 List<Class> list = exceptionType.getExceptionClasses(); 045 046 for (Class clazz : list) { 047 ExceptionPolicyKey key = new ExceptionPolicyKey(clazz, exceptionType.getOnWhen()); 048 exceptionPolicies.put(key, exceptionType); 049 } 050 } 051 052 /** 053 * Attempts to invoke the handler for this particular exception if one is available 054 */ 055 protected boolean customProcessorForException(Exchange exchange, Throwable exception) throws Exception { 056 ExceptionType policy = getExceptionPolicy(exchange, exception); 057 if (policy != null) { 058 Processor processor = policy.getErrorHandler(); 059 if (processor != null) { 060 processor.process(exchange); 061 return true; 062 } 063 } 064 return false; 065 } 066 067 /** 068 * Attempts to find the best suited {@link ExceptionType} to be used for handling the given thrown exception. 069 * 070 * @param exchange the exchange 071 * @param exception the exception that was thrown 072 * @return the best exception type to handle this exception, <tt>null</tt> if none found. 073 */ 074 protected ExceptionType getExceptionPolicy(Exchange exchange, Throwable exception) { 075 if (exceptionPolicy == null) { 076 throw new IllegalStateException("The exception policy has not been set"); 077 } 078 079 return exceptionPolicy.getExceptionPolicy(exceptionPolicies, exchange, exception); 080 } 081 082 /** 083 * Sets the strategy to use for resolving the {@link ExceptionType} to use 084 * for handling thrown exceptions. 085 */ 086 public void setExceptionPolicy(ExceptionPolicyStrategy exceptionPolicy) { 087 this.exceptionPolicy = exceptionPolicy; 088 } 089 090 /** 091 * Creates the default exception policy strategy to use. 092 */ 093 public static ExceptionPolicyStrategy createDefaultExceptionPolicyStrategy() { 094 return new DefaultExceptionPolicyStrategy(); 095 } 096 097 }