| 1 | /* |
| 2 | * Copyright 2006-2013 the original author or authors. |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | package org.springframework.batch.core.step.item; |
| 17 | |
| 18 | import java.util.Collection; |
| 19 | |
| 20 | import org.apache.commons.logging.Log; |
| 21 | import org.apache.commons.logging.LogFactory; |
| 22 | import org.springframework.batch.repeat.RepeatContext; |
| 23 | import org.springframework.batch.repeat.exception.ExceptionHandler; |
| 24 | import org.springframework.batch.repeat.support.RepeatSynchronizationManager; |
| 25 | import org.springframework.classify.BinaryExceptionClassifier; |
| 26 | import org.springframework.retry.RetryCallback; |
| 27 | import org.springframework.retry.RetryContext; |
| 28 | import org.springframework.retry.RetryPolicy; |
| 29 | import org.springframework.retry.listener.RetryListenerSupport; |
| 30 | |
| 31 | /** |
| 32 | * An {@link ExceptionHandler} that is aware of the retry context so that it can |
| 33 | * distinguish between a fatal exception and one that can be retried. Delegates |
| 34 | * the actual exception handling to another {@link ExceptionHandler}. |
| 35 | * |
| 36 | * @author Dave Syer |
| 37 | * |
| 38 | */ |
| 39 | public class SimpleRetryExceptionHandler extends RetryListenerSupport implements ExceptionHandler { |
| 40 | |
| 41 | /** |
| 42 | * Attribute key, whose existence signals an exhausted retry. |
| 43 | */ |
| 44 | private static final String EXHAUSTED = SimpleRetryExceptionHandler.class.getName() + ".RETRY_EXHAUSTED"; |
| 45 | |
| 46 | private static final Log logger = LogFactory.getLog(SimpleRetryExceptionHandler.class); |
| 47 | |
| 48 | final private RetryPolicy retryPolicy; |
| 49 | |
| 50 | final private ExceptionHandler exceptionHandler; |
| 51 | |
| 52 | final private BinaryExceptionClassifier fatalExceptionClassifier; |
| 53 | |
| 54 | /** |
| 55 | * Create an exception handler from its mandatory properties. |
| 56 | * |
| 57 | * @param retryPolicy the retry policy that will be under effect when an |
| 58 | * exception is encountered |
| 59 | * @param exceptionHandler the delegate to use if an exception actually |
| 60 | * needs to be handled |
| 61 | * @param fatalExceptionClasses |
| 62 | */ |
| 63 | public SimpleRetryExceptionHandler(RetryPolicy retryPolicy, ExceptionHandler exceptionHandler, Collection<Class<? extends Throwable>> fatalExceptionClasses) { |
| 64 | this.retryPolicy = retryPolicy; |
| 65 | this.exceptionHandler = exceptionHandler; |
| 66 | this.fatalExceptionClassifier = new BinaryExceptionClassifier(fatalExceptionClasses); |
| 67 | } |
| 68 | |
| 69 | /** |
| 70 | * Check if the exception is going to be retried, and veto the handling if |
| 71 | * it is. If retry is exhausted or the exception is on the fatal list, then |
| 72 | * handle using the delegate. |
| 73 | * |
| 74 | * @see ExceptionHandler#handleException(org.springframework.batch.repeat.RepeatContext, |
| 75 | * java.lang.Throwable) |
| 76 | */ |
| 77 | @Override |
| 78 | public void handleException(RepeatContext context, Throwable throwable) throws Throwable { |
| 79 | // Only bother to check the delegate exception handler if we know that |
| 80 | // retry is exhausted |
| 81 | if (fatalExceptionClassifier.classify(throwable) || context.hasAttribute(EXHAUSTED)) { |
| 82 | logger.debug("Handled fatal exception"); |
| 83 | exceptionHandler.handleException(context, throwable); |
| 84 | } |
| 85 | else { |
| 86 | logger.debug("Handled non-fatal exception", throwable); |
| 87 | } |
| 88 | } |
| 89 | |
| 90 | /** |
| 91 | * If retry is exhausted set up some state in the context that can be used |
| 92 | * to signal that the exception should be handled. |
| 93 | * |
| 94 | * @see org.springframework.retry.RetryListener#close(org.springframework.retry.RetryContext, |
| 95 | * org.springframework.retry.RetryCallback, java.lang.Throwable) |
| 96 | */ |
| 97 | @Override |
| 98 | public <T> void close(RetryContext context, RetryCallback<T> callback, Throwable throwable) { |
| 99 | if (!retryPolicy.canRetry(context)) { |
| 100 | logger.debug("Marking retry as exhausted: "+context); |
| 101 | getRepeatContext().setAttribute(EXHAUSTED, "true"); |
| 102 | } |
| 103 | } |
| 104 | |
| 105 | /** |
| 106 | * Get the parent context (the retry is in an inner "chunk" loop and we want |
| 107 | * the exception to be handled at the outer "step" level). |
| 108 | * @return the {@link RepeatContext} that should hold the exhausted flag. |
| 109 | */ |
| 110 | private RepeatContext getRepeatContext() { |
| 111 | RepeatContext context = RepeatSynchronizationManager.getContext(); |
| 112 | if (context.getParent() != null) { |
| 113 | return context.getParent(); |
| 114 | } |
| 115 | return context; |
| 116 | } |
| 117 | |
| 118 | } |