001/* 002 * Copyright 2006-2013 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016package org.springframework.batch.core.step.item; 017 018import org.apache.commons.logging.Log; 019import org.apache.commons.logging.LogFactory; 020import org.springframework.batch.repeat.RepeatContext; 021import org.springframework.batch.repeat.exception.ExceptionHandler; 022import org.springframework.batch.repeat.support.RepeatSynchronizationManager; 023import org.springframework.classify.BinaryExceptionClassifier; 024import org.springframework.retry.RetryCallback; 025import org.springframework.retry.RetryContext; 026import org.springframework.retry.RetryPolicy; 027import org.springframework.retry.listener.RetryListenerSupport; 028 029import java.util.Collection; 030 031/** 032 * An {@link ExceptionHandler} that is aware of the retry context so that it can 033 * distinguish between a fatal exception and one that can be retried. Delegates 034 * the actual exception handling to another {@link ExceptionHandler}. 035 * 036 * @author Dave Syer 037 * 038 */ 039public class SimpleRetryExceptionHandler extends RetryListenerSupport implements ExceptionHandler { 040 041 /** 042 * Attribute key, whose existence signals an exhausted retry. 043 */ 044 private static final String EXHAUSTED = SimpleRetryExceptionHandler.class.getName() + ".RETRY_EXHAUSTED"; 045 046 private static final Log logger = LogFactory.getLog(SimpleRetryExceptionHandler.class); 047 048 final private RetryPolicy retryPolicy; 049 050 final private ExceptionHandler exceptionHandler; 051 052 final private BinaryExceptionClassifier fatalExceptionClassifier; 053 054 /** 055 * Create an exception handler from its mandatory properties. 056 * 057 * @param retryPolicy the retry policy that will be under effect when an 058 * exception is encountered 059 * @param exceptionHandler the delegate to use if an exception actually 060 * needs to be handled 061 * @param fatalExceptionClasses exceptions 062 */ 063 public SimpleRetryExceptionHandler(RetryPolicy retryPolicy, ExceptionHandler exceptionHandler, Collection<Class<? extends Throwable>> fatalExceptionClasses) { 064 this.retryPolicy = retryPolicy; 065 this.exceptionHandler = exceptionHandler; 066 this.fatalExceptionClassifier = new BinaryExceptionClassifier(fatalExceptionClasses); 067 } 068 069 /** 070 * Check if the exception is going to be retried, and veto the handling if 071 * it is. If retry is exhausted or the exception is on the fatal list, then 072 * handle using the delegate. 073 * 074 * @see ExceptionHandler#handleException(org.springframework.batch.repeat.RepeatContext, 075 * java.lang.Throwable) 076 */ 077 @Override 078 public void handleException(RepeatContext context, Throwable throwable) throws Throwable { 079 // Only bother to check the delegate exception handler if we know that 080 // retry is exhausted 081 if (fatalExceptionClassifier.classify(throwable) || context.hasAttribute(EXHAUSTED)) { 082 logger.debug("Handled fatal exception"); 083 exceptionHandler.handleException(context, throwable); 084 } 085 else { 086 logger.debug("Handled non-fatal exception", throwable); 087 } 088 } 089 090 /** 091 * If retry is exhausted set up some state in the context that can be used 092 * to signal that the exception should be handled. 093 * 094 * @see org.springframework.retry.RetryListener#close(org.springframework.retry.RetryContext, 095 * org.springframework.retry.RetryCallback, java.lang.Throwable) 096 */ 097 @Override 098 public <T, E extends Throwable> void close(RetryContext context, RetryCallback<T, E> callback, Throwable throwable) { 099 if (!retryPolicy.canRetry(context)) { 100 if (logger.isDebugEnabled()) { 101 logger.debug("Marking retry as exhausted: "+context); 102 } 103 getRepeatContext().setAttribute(EXHAUSTED, "true"); 104 } 105 } 106 107 /** 108 * Get the parent context (the retry is in an inner "chunk" loop and we want 109 * the exception to be handled at the outer "step" level). 110 * @return the {@link RepeatContext} that should hold the exhausted flag. 111 */ 112 private RepeatContext getRepeatContext() { 113 RepeatContext context = RepeatSynchronizationManager.getContext(); 114 if (context.getParent() != null) { 115 return context.getParent(); 116 } 117 return context; 118 } 119 120}