| 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 | package org.springframework.batch.core.step.tasklet; |
| 17 | |
| 18 | import java.util.concurrent.Semaphore; |
| 19 | |
| 20 | import org.apache.commons.logging.Log; |
| 21 | import org.apache.commons.logging.LogFactory; |
| 22 | import org.springframework.batch.core.BatchStatus; |
| 23 | import org.springframework.batch.core.ChunkListener; |
| 24 | import org.springframework.batch.core.JobInterruptedException; |
| 25 | import org.springframework.batch.core.StepContribution; |
| 26 | import org.springframework.batch.core.StepExecution; |
| 27 | import org.springframework.batch.core.StepExecutionListener; |
| 28 | import org.springframework.batch.core.listener.CompositeChunkListener; |
| 29 | import org.springframework.batch.core.repository.JobRepository; |
| 30 | import org.springframework.batch.core.scope.context.ChunkContext; |
| 31 | import org.springframework.batch.core.scope.context.StepContextRepeatCallback; |
| 32 | import org.springframework.batch.core.step.AbstractStep; |
| 33 | import org.springframework.batch.core.step.FatalStepExecutionException; |
| 34 | import org.springframework.batch.core.step.StepInterruptionPolicy; |
| 35 | import org.springframework.batch.core.step.ThreadStepInterruptionPolicy; |
| 36 | import org.springframework.batch.item.ExecutionContext; |
| 37 | import org.springframework.batch.item.ItemReader; |
| 38 | import org.springframework.batch.item.ItemStream; |
| 39 | import org.springframework.batch.item.ItemWriter; |
| 40 | import org.springframework.batch.item.support.CompositeItemStream; |
| 41 | import org.springframework.batch.repeat.RepeatContext; |
| 42 | import org.springframework.batch.repeat.RepeatOperations; |
| 43 | import org.springframework.batch.repeat.RepeatStatus; |
| 44 | import org.springframework.batch.repeat.support.RepeatTemplate; |
| 45 | import org.springframework.transaction.PlatformTransactionManager; |
| 46 | import org.springframework.transaction.TransactionStatus; |
| 47 | import org.springframework.transaction.interceptor.DefaultTransactionAttribute; |
| 48 | import org.springframework.transaction.interceptor.TransactionAttribute; |
| 49 | import org.springframework.transaction.support.TransactionCallback; |
| 50 | import org.springframework.transaction.support.TransactionSynchronization; |
| 51 | import org.springframework.transaction.support.TransactionSynchronizationAdapter; |
| 52 | import org.springframework.transaction.support.TransactionSynchronizationManager; |
| 53 | import org.springframework.transaction.support.TransactionTemplate; |
| 54 | import org.springframework.util.Assert; |
| 55 | |
| 56 | /** |
| 57 | * Simple implementation of executing the step as a call to a {@link Tasklet}, |
| 58 | * possibly repeated, and each call surrounded by a transaction. The structure |
| 59 | * is therefore that of a loop with transaction boundary inside the loop. The |
| 60 | * loop is controlled by the step operations ( |
| 61 | * {@link #setStepOperations(RepeatOperations)}).<br/> |
| 62 | * <br/> |
| 63 | * |
| 64 | * Clients can use interceptors in the step operations to intercept or listen to |
| 65 | * the iteration on a step-wide basis, for instance to get a callback when the |
| 66 | * step is complete. Those that want callbacks at the level of an individual |
| 67 | * tasks, can specify interceptors for the chunk operations. |
| 68 | * |
| 69 | * @author Dave Syer |
| 70 | * @author Lucas Ward |
| 71 | * @author Ben Hale |
| 72 | * @author Robert Kasanicky |
| 73 | */ |
| 74 | public class TaskletStep extends AbstractStep { |
| 75 | |
| 76 | private static final Log logger = LogFactory.getLog(TaskletStep.class); |
| 77 | |
| 78 | private RepeatOperations stepOperations = new RepeatTemplate(); |
| 79 | |
| 80 | private CompositeChunkListener chunkListener = new CompositeChunkListener(); |
| 81 | |
| 82 | // default to checking current thread for interruption. |
| 83 | private StepInterruptionPolicy interruptionPolicy = new ThreadStepInterruptionPolicy(); |
| 84 | |
| 85 | private CompositeItemStream stream = new CompositeItemStream(); |
| 86 | |
| 87 | private PlatformTransactionManager transactionManager; |
| 88 | |
| 89 | private TransactionAttribute transactionAttribute = new DefaultTransactionAttribute() { |
| 90 | |
| 91 | @Override |
| 92 | public boolean rollbackOn(Throwable ex) { |
| 93 | return true; |
| 94 | } |
| 95 | |
| 96 | }; |
| 97 | |
| 98 | private Tasklet tasklet; |
| 99 | |
| 100 | /** |
| 101 | * Default constructor. |
| 102 | */ |
| 103 | public TaskletStep() { |
| 104 | this(null); |
| 105 | } |
| 106 | |
| 107 | /** |
| 108 | * @param name |
| 109 | */ |
| 110 | public TaskletStep(String name) { |
| 111 | super(name); |
| 112 | } |
| 113 | |
| 114 | /* |
| 115 | * (non-Javadoc) |
| 116 | * |
| 117 | * @see |
| 118 | * org.springframework.batch.core.step.AbstractStep#afterPropertiesSet() |
| 119 | */ |
| 120 | @Override |
| 121 | public void afterPropertiesSet() throws Exception { |
| 122 | super.afterPropertiesSet(); |
| 123 | Assert.state(transactionManager != null, "A transaction manager must be provided"); |
| 124 | } |
| 125 | |
| 126 | /** |
| 127 | * Public setter for the {@link PlatformTransactionManager}. |
| 128 | * |
| 129 | * @param transactionManager the transaction manager to set |
| 130 | */ |
| 131 | public void setTransactionManager(PlatformTransactionManager transactionManager) { |
| 132 | this.transactionManager = transactionManager; |
| 133 | } |
| 134 | |
| 135 | /** |
| 136 | * Public setter for the {@link TransactionAttribute}. |
| 137 | * |
| 138 | * @param transactionAttribute the {@link TransactionAttribute} to set |
| 139 | */ |
| 140 | public void setTransactionAttribute(TransactionAttribute transactionAttribute) { |
| 141 | this.transactionAttribute = transactionAttribute; |
| 142 | } |
| 143 | |
| 144 | /** |
| 145 | * Public setter for the {@link Tasklet}. |
| 146 | * |
| 147 | * @param tasklet the {@link Tasklet} to set |
| 148 | */ |
| 149 | public void setTasklet(Tasklet tasklet) { |
| 150 | this.tasklet = tasklet; |
| 151 | if (tasklet instanceof StepExecutionListener) { |
| 152 | registerStepExecutionListener((StepExecutionListener) tasklet); |
| 153 | } |
| 154 | } |
| 155 | |
| 156 | /** |
| 157 | * Register a chunk listener for callbacks at the appropriate stages in a |
| 158 | * step execution. |
| 159 | * |
| 160 | * @param listener a {@link ChunkListener} |
| 161 | */ |
| 162 | public void registerChunkListener(ChunkListener listener) { |
| 163 | this.chunkListener.register(listener); |
| 164 | } |
| 165 | |
| 166 | /** |
| 167 | * Register each of the objects as listeners. |
| 168 | * |
| 169 | * @param listeners an array of listener objects of known types. |
| 170 | */ |
| 171 | public void setChunkListeners(ChunkListener[] listeners) { |
| 172 | for (int i = 0; i < listeners.length; i++) { |
| 173 | registerChunkListener(listeners[i]); |
| 174 | } |
| 175 | } |
| 176 | |
| 177 | /** |
| 178 | * Register each of the streams for callbacks at the appropriate time in the |
| 179 | * step. The {@link ItemReader} and {@link ItemWriter} are automatically |
| 180 | * registered, but it doesn't hurt to also register them here. Injected |
| 181 | * dependencies of the reader and writer are not automatically registered, |
| 182 | * so if you implement {@link ItemWriter} using delegation to another object |
| 183 | * which itself is a {@link ItemStream}, you need to register the delegate |
| 184 | * here. |
| 185 | * |
| 186 | * @param streams an array of {@link ItemStream} objects. |
| 187 | */ |
| 188 | public void setStreams(ItemStream[] streams) { |
| 189 | for (int i = 0; i < streams.length; i++) { |
| 190 | registerStream(streams[i]); |
| 191 | } |
| 192 | } |
| 193 | |
| 194 | /** |
| 195 | * Register a single {@link ItemStream} for callbacks to the stream |
| 196 | * interface. |
| 197 | * |
| 198 | * @param stream |
| 199 | */ |
| 200 | public void registerStream(ItemStream stream) { |
| 201 | this.stream.register(stream); |
| 202 | } |
| 203 | |
| 204 | /** |
| 205 | * The {@link RepeatOperations} to use for the outer loop of the batch |
| 206 | * processing. Should be set up by the caller through a factory. Defaults to |
| 207 | * a plain {@link RepeatTemplate}. |
| 208 | * |
| 209 | * @param stepOperations a {@link RepeatOperations} instance. |
| 210 | */ |
| 211 | public void setStepOperations(RepeatOperations stepOperations) { |
| 212 | this.stepOperations = stepOperations; |
| 213 | } |
| 214 | |
| 215 | /** |
| 216 | * Setter for the {@link StepInterruptionPolicy}. The policy is used to |
| 217 | * check whether an external request has been made to interrupt the job |
| 218 | * execution. |
| 219 | * |
| 220 | * @param interruptionPolicy a {@link StepInterruptionPolicy} |
| 221 | */ |
| 222 | public void setInterruptionPolicy(StepInterruptionPolicy interruptionPolicy) { |
| 223 | this.interruptionPolicy = interruptionPolicy; |
| 224 | } |
| 225 | |
| 226 | /** |
| 227 | * Process the step and update its context so that progress can be monitored |
| 228 | * by the caller. The step is broken down into chunks, each one executing in |
| 229 | * a transaction. The step and its execution and execution context are all |
| 230 | * given an up to date {@link BatchStatus}, and the {@link JobRepository} is |
| 231 | * used to store the result. Various reporting information are also added to |
| 232 | * the current context governing the step execution, which would normally be |
| 233 | * available to the caller through the step's {@link ExecutionContext}.<br/> |
| 234 | * |
| 235 | * @throws JobInterruptedException if the step or a chunk is interrupted |
| 236 | * @throws RuntimeException if there is an exception during a chunk |
| 237 | * execution |
| 238 | * |
| 239 | */ |
| 240 | @Override |
| 241 | protected void doExecute(StepExecution stepExecution) throws Exception { |
| 242 | |
| 243 | stream.update(stepExecution.getExecutionContext()); |
| 244 | getJobRepository().updateExecutionContext(stepExecution); |
| 245 | |
| 246 | // Shared semaphore per step execution, so other step executions can run |
| 247 | // in parallel without needing the lock |
| 248 | final Semaphore semaphore = createSemaphore(); |
| 249 | |
| 250 | stepOperations.iterate(new StepContextRepeatCallback(stepExecution) { |
| 251 | |
| 252 | @Override |
| 253 | public RepeatStatus doInChunkContext(RepeatContext repeatContext, ChunkContext chunkContext) |
| 254 | throws Exception { |
| 255 | |
| 256 | StepExecution stepExecution = chunkContext.getStepContext().getStepExecution(); |
| 257 | |
| 258 | // Before starting a new transaction, check for |
| 259 | // interruption. |
| 260 | interruptionPolicy.checkInterrupted(stepExecution); |
| 261 | |
| 262 | RepeatStatus result; |
| 263 | try { |
| 264 | result = (RepeatStatus) new TransactionTemplate(transactionManager, transactionAttribute) |
| 265 | .execute(new ChunkTransactionCallback(chunkContext, semaphore)); |
| 266 | } |
| 267 | catch (UncheckedTransactionException e) { |
| 268 | // Allow checked exceptions to be thrown inside callback |
| 269 | throw (Exception) e.getCause(); |
| 270 | } |
| 271 | |
| 272 | chunkListener.afterChunk(); |
| 273 | |
| 274 | // Check for interruption after transaction as well, so that |
| 275 | // the interrupted exception is correctly propagated up to |
| 276 | // caller |
| 277 | interruptionPolicy.checkInterrupted(stepExecution); |
| 278 | |
| 279 | return result; |
| 280 | } |
| 281 | |
| 282 | }); |
| 283 | |
| 284 | } |
| 285 | |
| 286 | /** |
| 287 | * Extension point mainly for test purposes so that the behaviour of the |
| 288 | * lock can be manipulated to simulate various pathologies. |
| 289 | * |
| 290 | * @return a semaphore for locking access to the JobRepository |
| 291 | */ |
| 292 | protected Semaphore createSemaphore() { |
| 293 | return new Semaphore(1); |
| 294 | } |
| 295 | |
| 296 | protected void close(ExecutionContext ctx) throws Exception { |
| 297 | stream.close(); |
| 298 | } |
| 299 | |
| 300 | protected void open(ExecutionContext ctx) throws Exception { |
| 301 | stream.open(ctx); |
| 302 | } |
| 303 | |
| 304 | /** |
| 305 | * A callback for the transactional work inside a chunk. Also detects |
| 306 | * failures in the transaction commit and rollback, only panicking if the |
| 307 | * transaction status is unknown (i.e. if a commit failure leads to a clean |
| 308 | * rollback then we assume the state is consistent). |
| 309 | * |
| 310 | * @author Dave Syer |
| 311 | * |
| 312 | */ |
| 313 | private class ChunkTransactionCallback extends TransactionSynchronizationAdapter implements TransactionCallback { |
| 314 | |
| 315 | private final StepExecution stepExecution; |
| 316 | |
| 317 | private final ChunkContext chunkContext; |
| 318 | |
| 319 | private boolean rolledBack = false; |
| 320 | |
| 321 | private boolean stepExecutionUpdated = false; |
| 322 | |
| 323 | private StepExecution oldVersion; |
| 324 | |
| 325 | private boolean locked = false; |
| 326 | |
| 327 | private final Semaphore semaphore; |
| 328 | |
| 329 | public ChunkTransactionCallback(ChunkContext chunkContext, Semaphore semaphore) { |
| 330 | this.chunkContext = chunkContext; |
| 331 | this.stepExecution = chunkContext.getStepContext().getStepExecution(); |
| 332 | this.semaphore = semaphore; |
| 333 | } |
| 334 | |
| 335 | @Override |
| 336 | public void afterCompletion(int status) { |
| 337 | try { |
| 338 | if (status != TransactionSynchronization.STATUS_COMMITTED) { |
| 339 | if (stepExecutionUpdated) { |
| 340 | // Wah! the commit failed. We need to rescue the step |
| 341 | // execution data. |
| 342 | logger.info("Commit failed while step execution data was already updated. " |
| 343 | + "Reverting to old version."); |
| 344 | copy(oldVersion, stepExecution); |
| 345 | if (status == TransactionSynchronization.STATUS_ROLLED_BACK) { |
| 346 | rollback(stepExecution); |
| 347 | } |
| 348 | } |
| 349 | } |
| 350 | if (status == TransactionSynchronization.STATUS_UNKNOWN) { |
| 351 | logger.error("Rolling back with transaction in unknown state"); |
| 352 | rollback(stepExecution); |
| 353 | stepExecution.upgradeStatus(BatchStatus.UNKNOWN); |
| 354 | stepExecution.setTerminateOnly(); |
| 355 | } |
| 356 | } |
| 357 | finally { |
| 358 | // Only release the lock if we acquired it, and release as late |
| 359 | // as possible |
| 360 | if (locked) { |
| 361 | semaphore.release(); |
| 362 | } |
| 363 | locked = false; |
| 364 | } |
| 365 | } |
| 366 | |
| 367 | public Object doInTransaction(TransactionStatus status) { |
| 368 | |
| 369 | TransactionSynchronizationManager.registerSynchronization(this); |
| 370 | |
| 371 | RepeatStatus result = RepeatStatus.CONTINUABLE; |
| 372 | |
| 373 | StepContribution contribution = stepExecution.createStepContribution(); |
| 374 | |
| 375 | chunkListener.beforeChunk(); |
| 376 | |
| 377 | // In case we need to push it back to its old value |
| 378 | // after a commit fails... |
| 379 | oldVersion = new StepExecution(stepExecution.getStepName(), stepExecution.getJobExecution()); |
| 380 | copy(stepExecution, oldVersion); |
| 381 | |
| 382 | try { |
| 383 | |
| 384 | try { |
| 385 | try { |
| 386 | result = tasklet.execute(contribution, chunkContext); |
| 387 | if (result == null) { |
| 388 | result = RepeatStatus.FINISHED; |
| 389 | } |
| 390 | } |
| 391 | catch (Exception e) { |
| 392 | if (transactionAttribute.rollbackOn(e)) { |
| 393 | throw e; |
| 394 | } |
| 395 | } |
| 396 | |
| 397 | } |
| 398 | finally { |
| 399 | |
| 400 | // If the step operations are asynchronous then we need |
| 401 | // to synchronize changes to the step execution (at a |
| 402 | // minimum). Take the lock *before* changing the step |
| 403 | // execution. |
| 404 | try { |
| 405 | semaphore.acquire(); |
| 406 | locked = true; |
| 407 | } |
| 408 | catch (InterruptedException e) { |
| 409 | logger.error("Thread interrupted while locking for repository update"); |
| 410 | stepExecution.setStatus(BatchStatus.STOPPED); |
| 411 | stepExecution.setTerminateOnly(); |
| 412 | Thread.currentThread().interrupt(); |
| 413 | } |
| 414 | |
| 415 | // Apply the contribution to the step |
| 416 | // even if unsuccessful |
| 417 | logger.debug("Applying contribution: " + contribution); |
| 418 | stepExecution.apply(contribution); |
| 419 | |
| 420 | } |
| 421 | |
| 422 | stepExecutionUpdated = true; |
| 423 | |
| 424 | stream.update(stepExecution.getExecutionContext()); |
| 425 | |
| 426 | try { |
| 427 | // Going to attempt a commit. If it fails this flag will |
| 428 | // stay false and we can use that later. |
| 429 | getJobRepository().updateExecutionContext(stepExecution); |
| 430 | stepExecution.incrementCommitCount(); |
| 431 | logger.debug("Saving step execution before commit: " + stepExecution); |
| 432 | getJobRepository().update(stepExecution); |
| 433 | } |
| 434 | catch (Exception e) { |
| 435 | // If we get to here there was a problem saving the step |
| 436 | // execution and we have to fail. |
| 437 | String msg = "JobRepository failure forcing exit with unknown status"; |
| 438 | logger.error(msg, e); |
| 439 | stepExecution.upgradeStatus(BatchStatus.UNKNOWN); |
| 440 | stepExecution.setTerminateOnly(); |
| 441 | throw new FatalStepExecutionException(msg, e); |
| 442 | } |
| 443 | |
| 444 | } |
| 445 | catch (Error e) { |
| 446 | logger.debug("Rollback for Error: " + e.getClass().getName() + ": " + e.getMessage()); |
| 447 | rollback(stepExecution); |
| 448 | throw e; |
| 449 | } |
| 450 | catch (RuntimeException e) { |
| 451 | logger.debug("Rollback for RuntimeException: " + e.getClass().getName() + ": " + e.getMessage()); |
| 452 | rollback(stepExecution); |
| 453 | throw e; |
| 454 | } |
| 455 | catch (Exception e) { |
| 456 | logger.debug("Rollback for Exception: " + e.getClass().getName() + ": " + e.getMessage()); |
| 457 | rollback(stepExecution); |
| 458 | // Allow checked exceptions |
| 459 | throw new UncheckedTransactionException(e); |
| 460 | } |
| 461 | |
| 462 | return result; |
| 463 | |
| 464 | } |
| 465 | |
| 466 | private void rollback(StepExecution stepExecution) { |
| 467 | if (!rolledBack) { |
| 468 | stepExecution.incrementRollbackCount(); |
| 469 | rolledBack = true; |
| 470 | } |
| 471 | } |
| 472 | |
| 473 | private void copy(final StepExecution source, final StepExecution target) { |
| 474 | target.setVersion(source.getVersion()); |
| 475 | target.setWriteCount(source.getWriteCount()); |
| 476 | target.setFilterCount(source.getFilterCount()); |
| 477 | target.setCommitCount(source.getCommitCount()); |
| 478 | target.setExecutionContext(new ExecutionContext(source.getExecutionContext())); |
| 479 | } |
| 480 | |
| 481 | } |
| 482 | |
| 483 | /** |
| 484 | * Convenience wrapper for a checked exception so that it can cause a |
| 485 | * rollback and be extracted afterwards. |
| 486 | * |
| 487 | * @author Dave Syer |
| 488 | * |
| 489 | */ |
| 490 | private static class UncheckedTransactionException extends RuntimeException { |
| 491 | |
| 492 | public UncheckedTransactionException(Exception e) { |
| 493 | super(e); |
| 494 | } |
| 495 | |
| 496 | } |
| 497 | |
| 498 | } |