| 1 | /* |
| 2 | * Copyright 2006-2007 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 | |
| 17 | package org.springframework.batch.core.step.item; |
| 18 | |
| 19 | import org.springframework.batch.classify.BinaryExceptionClassifier; |
| 20 | import org.springframework.batch.classify.Classifier; |
| 21 | import org.springframework.batch.core.StepContribution; |
| 22 | import org.springframework.batch.core.step.skip.LimitCheckingItemSkipPolicy; |
| 23 | import org.springframework.batch.core.step.skip.NonSkippableReadException; |
| 24 | import org.springframework.batch.core.step.skip.SkipException; |
| 25 | import org.springframework.batch.core.step.skip.SkipListenerFailedException; |
| 26 | import org.springframework.batch.core.step.skip.SkipPolicy; |
| 27 | import org.springframework.batch.core.step.skip.SkipPolicyFailedException; |
| 28 | import org.springframework.batch.item.ItemReader; |
| 29 | import org.springframework.batch.repeat.RepeatOperations; |
| 30 | |
| 31 | /** |
| 32 | * FaultTolerant implementation of the {@link ChunkProcessor} interface, that |
| 33 | * allows for skipping or retry of items that cause exceptions during reading or |
| 34 | * processing. |
| 35 | * |
| 36 | */ |
| 37 | public class FaultTolerantChunkProvider<I> extends SimpleChunkProvider<I> { |
| 38 | |
| 39 | /** |
| 40 | * Hard limit for number of read skips in the same chunk. Should be |
| 41 | * sufficiently high that it is only encountered in a runaway step where all |
| 42 | * items are skipped before the chunk can complete (leading to a potential |
| 43 | * heap memory problem). |
| 44 | */ |
| 45 | public static final int DEFAULT_MAX_SKIPS_ON_READ = 100; |
| 46 | |
| 47 | private SkipPolicy skipPolicy = new LimitCheckingItemSkipPolicy(); |
| 48 | |
| 49 | private Classifier<Throwable, Boolean> rollbackClassifier = new BinaryExceptionClassifier(true); |
| 50 | |
| 51 | private int maxSkipsOnRead = DEFAULT_MAX_SKIPS_ON_READ; |
| 52 | |
| 53 | public FaultTolerantChunkProvider(ItemReader<? extends I> itemReader, RepeatOperations repeatOperations) { |
| 54 | super(itemReader, repeatOperations); |
| 55 | } |
| 56 | |
| 57 | /** |
| 58 | * @param maxSkipsOnRead the maximum number of skips on read |
| 59 | */ |
| 60 | public void setMaxSkipsOnRead(int maxSkipsOnRead) { |
| 61 | this.maxSkipsOnRead = maxSkipsOnRead; |
| 62 | } |
| 63 | |
| 64 | /** |
| 65 | * The policy that determines whether exceptions can be skipped on read. |
| 66 | * @param SkipPolicy |
| 67 | */ |
| 68 | public void setSkipPolicy(SkipPolicy SkipPolicy) { |
| 69 | this.skipPolicy = SkipPolicy; |
| 70 | } |
| 71 | |
| 72 | /** |
| 73 | * Classifier to determine whether exceptions have been marked as |
| 74 | * no-rollback (as opposed to skippable). If ecnounterd they are simply |
| 75 | * ignored, unless also skippable. |
| 76 | * |
| 77 | * @param rollbackClassifier the rollback classifier to set |
| 78 | */ |
| 79 | public void setRollbackClassifier(Classifier<Throwable, Boolean> rollbackClassifier) { |
| 80 | this.rollbackClassifier = rollbackClassifier; |
| 81 | } |
| 82 | |
| 83 | @Override |
| 84 | protected I read(StepContribution contribution, Chunk<I> chunk) throws Exception { |
| 85 | while (true) { |
| 86 | try { |
| 87 | return doRead(); |
| 88 | } |
| 89 | catch (Exception e) { |
| 90 | |
| 91 | if (shouldSkip(skipPolicy, e, contribution.getStepSkipCount())) { |
| 92 | // increment skip count and try again |
| 93 | contribution.incrementReadSkipCount(); |
| 94 | chunk.skip(e); |
| 95 | |
| 96 | if (chunk.getErrors().size() >= maxSkipsOnRead) { |
| 97 | throw new SkipOverflowException("Too many skips on read"); |
| 98 | } |
| 99 | |
| 100 | logger.debug("Skipping failed input", e); |
| 101 | } |
| 102 | else { |
| 103 | if (rollbackClassifier.classify(e)) { |
| 104 | throw new NonSkippableReadException("Non-skippable exception during read", e); |
| 105 | } |
| 106 | logger.debug("No-rollback for non-skippable exception (ignored)", e); |
| 107 | } |
| 108 | |
| 109 | } |
| 110 | } |
| 111 | } |
| 112 | |
| 113 | @Override |
| 114 | public void postProcess(StepContribution contribution, Chunk<I> chunk) { |
| 115 | for (Exception e : chunk.getErrors()) { |
| 116 | try { |
| 117 | getListener().onSkipInRead(e); |
| 118 | } |
| 119 | catch (RuntimeException ex) { |
| 120 | throw new SkipListenerFailedException("Fatal exception in SkipListener.", ex, e); |
| 121 | } |
| 122 | } |
| 123 | } |
| 124 | |
| 125 | /** |
| 126 | * Convenience method for calling process skip policy. |
| 127 | * |
| 128 | * @param policy the skip policy |
| 129 | * @param e the cause of the skip |
| 130 | * @param skipCount the current skip count |
| 131 | */ |
| 132 | private boolean shouldSkip(SkipPolicy policy, Throwable e, int skipCount) { |
| 133 | try { |
| 134 | return policy.shouldSkip(e, skipCount); |
| 135 | } |
| 136 | catch (SkipException ex) { |
| 137 | throw ex; |
| 138 | } |
| 139 | catch (RuntimeException ex) { |
| 140 | throw new SkipPolicyFailedException("Fatal exception in SkipPolicy.", ex, e); |
| 141 | } |
| 142 | } |
| 143 | |
| 144 | } |