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.ExceptionPolicyStrategy;
029
030 /**
031 * Support class for {@link ErrorHandler} implementations.
032 *
033 * @version $Revision: 645359 $
034 */
035 public abstract class ErrorHandlerSupport extends ServiceSupport implements ErrorHandler {
036 private Map<Class, ExceptionType> exceptionPolicies = new LinkedHashMap<Class, ExceptionType>();
037 private ExceptionPolicyStrategy exceptionPolicy = createDefaultExceptionPolicyStrategy();
038
039 public void addExceptionPolicy(ExceptionType exception) {
040 Processor processor = exception.getErrorHandler();
041 addChildService(processor);
042
043 List<Class> list = exception.getExceptionClasses();
044
045 for (Class exceptionType : list) {
046 exceptionPolicies.put(exceptionType, exception);
047 }
048 }
049
050 /**
051 * Attempts to invoke the handler for this particular exception if one is available
052 */
053 protected boolean customProcessorForException(Exchange exchange, Throwable exception) throws Exception {
054 ExceptionType policy = getExceptionPolicy(exchange, exception);
055 if (policy != null) {
056 Processor processor = policy.getErrorHandler();
057 if (processor != null) {
058 processor.process(exchange);
059 return true;
060 }
061 }
062 return false;
063 }
064
065 /**
066 * Attempts to find the best suited {@link ExceptionType} to be used for handling the given thrown exception.
067 *
068 * @param exchange the exchange
069 * @param exception the exception that was thrown
070 * @return the best exception type to handle this exception, <tt>null</tt> if none found.
071 */
072 protected ExceptionType getExceptionPolicy(Exchange exchange, Throwable exception) {
073 if (exceptionPolicy == null) {
074 throw new IllegalStateException("The exception policy has not been set");
075 }
076
077 return exceptionPolicy.getExceptionPolicy(exceptionPolicies, exchange, exception);
078 }
079
080 /**
081 * Sets the strategy to use for resolving the {@link ExceptionType} to use
082 * for handling thrown exceptions.
083 */
084 public void setExceptionPolicy(ExceptionPolicyStrategy exceptionPolicy) {
085 this.exceptionPolicy = exceptionPolicy;
086 }
087
088 /**
089 * Creates the default exception policy strategy to use.
090 */
091 public static ExceptionPolicyStrategy createDefaultExceptionPolicyStrategy() {
092 return new DefaultExceptionPolicyStrategy();
093 }
094
095 }