| 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 | |
| 17 | package org.springframework.batch.core.step.item; |
| 18 | |
| 19 | import java.util.ArrayList; |
| 20 | import java.util.Collection; |
| 21 | import java.util.Iterator; |
| 22 | import java.util.List; |
| 23 | |
| 24 | import org.springframework.classify.Classifier; |
| 25 | import org.springframework.retry.ExhaustedRetryException; |
| 26 | import org.springframework.retry.RecoveryCallback; |
| 27 | import org.springframework.retry.RetryCallback; |
| 28 | import org.springframework.retry.RetryContext; |
| 29 | import org.springframework.retry.RetryListener; |
| 30 | import org.springframework.retry.RetryOperations; |
| 31 | import org.springframework.retry.RetryPolicy; |
| 32 | import org.springframework.retry.RetryState; |
| 33 | import org.springframework.retry.backoff.BackOffPolicy; |
| 34 | import org.springframework.retry.context.RetryContextSupport; |
| 35 | import org.springframework.retry.policy.RetryContextCache; |
| 36 | import org.springframework.retry.support.DefaultRetryState; |
| 37 | import org.springframework.retry.support.RetrySynchronizationManager; |
| 38 | import org.springframework.retry.support.RetryTemplate; |
| 39 | |
| 40 | /** |
| 41 | * A special purpose retry template that deals specifically with multi-valued |
| 42 | * stateful retry. This is useful in the case where the operation to be retried |
| 43 | * operates on multiple items, and when it fails there is no way to decide which |
| 44 | * (if any) of the items was responsible. The {@link RetryState} used in the |
| 45 | * execute methods is composite, and when a failure occurs, all of the keys in |
| 46 | * the composite are "tarred with the same brush". Subsequent attempts to |
| 47 | * execute with any of the keys that have failed previously results in a new |
| 48 | * attempt and the previous state is used to check the {@link RetryPolicy}. If |
| 49 | * one of the failed items eventually succeeds then the others in the current |
| 50 | * composite for that attempt will be cleared from the context cache (as |
| 51 | * normal), but there may still be entries in the cache for the original failed |
| 52 | * items. This might mean that an item that did not cause a failure is never |
| 53 | * retried because other items in the same batch fail fatally first. |
| 54 | * |
| 55 | * @author Dave Syer |
| 56 | * |
| 57 | */ |
| 58 | public class BatchRetryTemplate implements RetryOperations { |
| 59 | |
| 60 | private class BatchRetryState extends DefaultRetryState { |
| 61 | |
| 62 | private final Collection<RetryState> keys; |
| 63 | |
| 64 | public BatchRetryState(Collection<RetryState> keys) { |
| 65 | super(keys); |
| 66 | this.keys = new ArrayList<RetryState>(keys); |
| 67 | } |
| 68 | |
| 69 | } |
| 70 | |
| 71 | @SuppressWarnings("serial") |
| 72 | private static class BatchRetryContext extends RetryContextSupport { |
| 73 | |
| 74 | private final Collection<RetryContext> contexts; |
| 75 | |
| 76 | public BatchRetryContext(RetryContext parent, Collection<RetryContext> contexts) { |
| 77 | |
| 78 | super(parent); |
| 79 | |
| 80 | this.contexts = contexts; |
| 81 | int count = 0; |
| 82 | |
| 83 | for (RetryContext context : contexts) { |
| 84 | int retryCount = context.getRetryCount(); |
| 85 | if (retryCount > count) { |
| 86 | count = retryCount; |
| 87 | registerThrowable(context.getLastThrowable()); |
| 88 | } |
| 89 | } |
| 90 | |
| 91 | } |
| 92 | |
| 93 | } |
| 94 | |
| 95 | private static class InnerRetryTemplate extends RetryTemplate { |
| 96 | |
| 97 | @Override |
| 98 | protected boolean canRetry(RetryPolicy retryPolicy, RetryContext context) { |
| 99 | |
| 100 | BatchRetryContext batchContext = (BatchRetryContext) context; |
| 101 | |
| 102 | for (RetryContext nextContext : batchContext.contexts) { |
| 103 | if (!super.canRetry(retryPolicy, nextContext)) { |
| 104 | return false; |
| 105 | } |
| 106 | } |
| 107 | |
| 108 | return true; |
| 109 | |
| 110 | } |
| 111 | |
| 112 | @Override |
| 113 | protected RetryContext open(RetryPolicy retryPolicy, RetryState state) { |
| 114 | |
| 115 | BatchRetryState batchState = (BatchRetryState) state; |
| 116 | |
| 117 | Collection<RetryContext> contexts = new ArrayList<RetryContext>(); |
| 118 | for (RetryState retryState : batchState.keys) { |
| 119 | contexts.add(super.open(retryPolicy, retryState)); |
| 120 | } |
| 121 | |
| 122 | return new BatchRetryContext(RetrySynchronizationManager.getContext(), contexts); |
| 123 | |
| 124 | } |
| 125 | |
| 126 | @Override |
| 127 | protected void registerThrowable(RetryPolicy retryPolicy, RetryState state, RetryContext context, Throwable e) { |
| 128 | |
| 129 | BatchRetryState batchState = (BatchRetryState) state; |
| 130 | BatchRetryContext batchContext = (BatchRetryContext) context; |
| 131 | |
| 132 | Iterator<RetryContext> contextIterator = batchContext.contexts.iterator(); |
| 133 | for (RetryState retryState : batchState.keys) { |
| 134 | RetryContext nextContext = contextIterator.next(); |
| 135 | super.registerThrowable(retryPolicy, retryState, nextContext, e); |
| 136 | } |
| 137 | |
| 138 | } |
| 139 | |
| 140 | @Override |
| 141 | protected void close(RetryPolicy retryPolicy, RetryContext context, RetryState state, boolean succeeded) { |
| 142 | |
| 143 | BatchRetryState batchState = (BatchRetryState) state; |
| 144 | BatchRetryContext batchContext = (BatchRetryContext) context; |
| 145 | |
| 146 | Iterator<RetryContext> contextIterator = batchContext.contexts.iterator(); |
| 147 | for (RetryState retryState : batchState.keys) { |
| 148 | RetryContext nextContext = contextIterator.next(); |
| 149 | super.close(retryPolicy, nextContext, retryState, succeeded); |
| 150 | } |
| 151 | |
| 152 | } |
| 153 | |
| 154 | @Override |
| 155 | protected <T> T handleRetryExhausted(RecoveryCallback<T> recoveryCallback, RetryContext context, |
| 156 | RetryState state) throws Exception { |
| 157 | |
| 158 | BatchRetryState batchState = (BatchRetryState) state; |
| 159 | BatchRetryContext batchContext = (BatchRetryContext) context; |
| 160 | |
| 161 | // Accumulate exceptions to be thrown so all the keys get a crack |
| 162 | Exception rethrowable = null; |
| 163 | ExhaustedRetryException exhausted = null; |
| 164 | |
| 165 | Iterator<RetryContext> contextIterator = batchContext.contexts.iterator(); |
| 166 | for (RetryState retryState : batchState.keys) { |
| 167 | |
| 168 | RetryContext nextContext = contextIterator.next(); |
| 169 | |
| 170 | try { |
| 171 | super.handleRetryExhausted(null, nextContext, retryState); |
| 172 | } |
| 173 | catch (ExhaustedRetryException e) { |
| 174 | exhausted = e; |
| 175 | } |
| 176 | catch (Exception e) { |
| 177 | rethrowable = e; |
| 178 | } |
| 179 | |
| 180 | } |
| 181 | |
| 182 | if (recoveryCallback != null) { |
| 183 | return recoveryCallback.recover(context); |
| 184 | } |
| 185 | |
| 186 | if (exhausted != null) { |
| 187 | throw exhausted; |
| 188 | } |
| 189 | |
| 190 | throw rethrowable; |
| 191 | |
| 192 | } |
| 193 | |
| 194 | } |
| 195 | |
| 196 | private final InnerRetryTemplate delegate = new InnerRetryTemplate(); |
| 197 | |
| 198 | private final RetryTemplate regular = new RetryTemplate(); |
| 199 | |
| 200 | private RetryPolicy retryPolicy; |
| 201 | |
| 202 | public <T> T execute(RetryCallback<T> retryCallback, Collection<RetryState> states) throws ExhaustedRetryException, |
| 203 | Exception { |
| 204 | RetryState batchState = new BatchRetryState(states); |
| 205 | return delegate.execute(retryCallback, batchState); |
| 206 | } |
| 207 | |
| 208 | public <T> T execute(RetryCallback<T> retryCallback, RecoveryCallback<T> recoveryCallback, |
| 209 | Collection<RetryState> states) throws ExhaustedRetryException, Exception { |
| 210 | RetryState batchState = new BatchRetryState(states); |
| 211 | return delegate.execute(retryCallback, recoveryCallback, batchState); |
| 212 | } |
| 213 | |
| 214 | @Override |
| 215 | public final <T> T execute(RetryCallback<T> retryCallback, RecoveryCallback<T> recoveryCallback, |
| 216 | RetryState retryState) throws Exception, ExhaustedRetryException { |
| 217 | return regular.execute(retryCallback, recoveryCallback, retryState); |
| 218 | } |
| 219 | |
| 220 | @Override |
| 221 | public final <T> T execute(RetryCallback<T> retryCallback, RecoveryCallback<T> recoveryCallback) throws Exception { |
| 222 | return regular.execute(retryCallback, recoveryCallback); |
| 223 | } |
| 224 | |
| 225 | @Override |
| 226 | public final <T> T execute(RetryCallback<T> retryCallback, RetryState retryState) throws Exception, |
| 227 | ExhaustedRetryException { |
| 228 | return regular.execute(retryCallback, retryState); |
| 229 | } |
| 230 | |
| 231 | @Override |
| 232 | public final <T> T execute(RetryCallback<T> retryCallback) throws Exception { |
| 233 | return regular.execute(retryCallback); |
| 234 | } |
| 235 | |
| 236 | public static List<RetryState> createState(List<?> keys) { |
| 237 | List<RetryState> states = new ArrayList<RetryState>(); |
| 238 | for (Object key : keys) { |
| 239 | states.add(new DefaultRetryState(key)); |
| 240 | } |
| 241 | return states; |
| 242 | } |
| 243 | |
| 244 | public static List<RetryState> createState(List<?> keys, Classifier<? super Throwable, Boolean> classifier) { |
| 245 | List<RetryState> states = new ArrayList<RetryState>(); |
| 246 | for (Object key : keys) { |
| 247 | states.add(new DefaultRetryState(key, classifier)); |
| 248 | } |
| 249 | return states; |
| 250 | } |
| 251 | |
| 252 | public void registerListener(RetryListener listener) { |
| 253 | delegate.registerListener(listener); |
| 254 | regular.registerListener(listener); |
| 255 | } |
| 256 | |
| 257 | public void setBackOffPolicy(BackOffPolicy backOffPolicy) { |
| 258 | delegate.setBackOffPolicy(backOffPolicy); |
| 259 | regular.setBackOffPolicy(backOffPolicy); |
| 260 | } |
| 261 | |
| 262 | public void setListeners(RetryListener[] listeners) { |
| 263 | delegate.setListeners(listeners); |
| 264 | regular.setListeners(listeners); |
| 265 | } |
| 266 | |
| 267 | public void setRetryContextCache(RetryContextCache retryContextCache) { |
| 268 | delegate.setRetryContextCache(retryContextCache); |
| 269 | regular.setRetryContextCache(retryContextCache); |
| 270 | } |
| 271 | |
| 272 | public void setRetryPolicy(RetryPolicy retryPolicy) { |
| 273 | this.retryPolicy = retryPolicy; |
| 274 | delegate.setRetryPolicy(retryPolicy); |
| 275 | regular.setRetryPolicy(retryPolicy); |
| 276 | } |
| 277 | |
| 278 | public boolean canRetry(RetryContext context) { |
| 279 | return context==null ? true : retryPolicy.canRetry(context); |
| 280 | } |
| 281 | |
| 282 | } |