| 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 java.util.ArrayList; |
| 20 | import java.util.Collection; |
| 21 | import java.util.HashMap; |
| 22 | import java.util.HashSet; |
| 23 | import java.util.List; |
| 24 | import java.util.Map; |
| 25 | |
| 26 | import org.springframework.batch.classify.BinaryExceptionClassifier; |
| 27 | import org.springframework.batch.classify.Classifier; |
| 28 | import org.springframework.batch.classify.SubclassClassifier; |
| 29 | import org.springframework.batch.core.JobInterruptedException; |
| 30 | import org.springframework.batch.core.Step; |
| 31 | import org.springframework.batch.core.step.skip.LimitCheckingItemSkipPolicy; |
| 32 | import org.springframework.batch.core.step.skip.NonSkippableReadException; |
| 33 | import org.springframework.batch.core.step.skip.SkipLimitExceededException; |
| 34 | import org.springframework.batch.core.step.skip.SkipListenerFailedException; |
| 35 | import org.springframework.batch.core.step.skip.SkipPolicy; |
| 36 | import org.springframework.batch.core.step.tasklet.TaskletStep; |
| 37 | import org.springframework.batch.item.ItemReader; |
| 38 | import org.springframework.batch.item.ItemStream; |
| 39 | import org.springframework.batch.repeat.RepeatOperations; |
| 40 | import org.springframework.batch.repeat.support.RepeatTemplate; |
| 41 | import org.springframework.batch.retry.ExhaustedRetryException; |
| 42 | import org.springframework.batch.retry.RetryException; |
| 43 | import org.springframework.batch.retry.RetryListener; |
| 44 | import org.springframework.batch.retry.RetryPolicy; |
| 45 | import org.springframework.batch.retry.backoff.BackOffPolicy; |
| 46 | import org.springframework.batch.retry.policy.ExceptionClassifierRetryPolicy; |
| 47 | import org.springframework.batch.retry.policy.MapRetryContextCache; |
| 48 | import org.springframework.batch.retry.policy.NeverRetryPolicy; |
| 49 | import org.springframework.batch.retry.policy.RetryContextCache; |
| 50 | import org.springframework.batch.retry.policy.SimpleRetryPolicy; |
| 51 | import org.springframework.core.task.SyncTaskExecutor; |
| 52 | import org.springframework.core.task.TaskExecutor; |
| 53 | import org.springframework.transaction.interceptor.DefaultTransactionAttribute; |
| 54 | import org.springframework.transaction.interceptor.TransactionAttribute; |
| 55 | |
| 56 | /** |
| 57 | * Factory bean for step that provides options for configuring skip behaviour. |
| 58 | * User can set {@link #setSkipLimit(int)} to set how many exceptions of |
| 59 | * {@link #setSkippableExceptionClasses(Collection)} types are tolerated. |
| 60 | * {@link #setFatalExceptionClasses(Collection)} will cause immediate |
| 61 | * termination of job - they are treated as higher priority than |
| 62 | * {@link #setSkippableExceptionClasses(Collection)}, so the two lists don't |
| 63 | * need to be exclusive. |
| 64 | * |
| 65 | * Skippable exceptions on write will by default cause transaction rollback - to |
| 66 | * avoid rollback for specific exception class include it in the transaction |
| 67 | * attribute as "no rollback for". |
| 68 | * |
| 69 | * @see SimpleStepFactoryBean |
| 70 | * |
| 71 | * @author Dave Syer |
| 72 | * @author Robert Kasanicky |
| 73 | * |
| 74 | */ |
| 75 | public class FaultTolerantStepFactoryBean<T, S> extends SimpleStepFactoryBean<T, S> { |
| 76 | |
| 77 | private Collection<Class<? extends Throwable>> skippableExceptionClasses = new HashSet<Class<? extends Throwable>>(); |
| 78 | |
| 79 | private Collection<Class<? extends Throwable>> noRollbackExceptionClasses = new HashSet<Class<? extends Throwable>>(); |
| 80 | |
| 81 | private Collection<Class<? extends Throwable>> fatalExceptionClasses = new HashSet<Class<? extends Throwable>>(); |
| 82 | |
| 83 | private Collection<Class<? extends Throwable>> nonRetryableExceptionClasses = new HashSet<Class<? extends Throwable>>(); |
| 84 | |
| 85 | private Collection<Class<? extends Throwable>> retryableExceptionClasses = new HashSet<Class<? extends Throwable>>(); |
| 86 | |
| 87 | private int cacheCapacity = 0; |
| 88 | |
| 89 | private int retryLimit = 0; |
| 90 | |
| 91 | private int skipLimit = 0; |
| 92 | |
| 93 | private BackOffPolicy backOffPolicy; |
| 94 | |
| 95 | private RetryListener[] retryListeners; |
| 96 | |
| 97 | private RetryPolicy retryPolicy; |
| 98 | |
| 99 | private RetryContextCache retryContextCache; |
| 100 | |
| 101 | private KeyGenerator keyGenerator; |
| 102 | |
| 103 | private ChunkMonitor chunkMonitor = new ChunkMonitor(); |
| 104 | |
| 105 | /** |
| 106 | * The {@link KeyGenerator} to use to identify failed items across rollback. |
| 107 | * Not used in the case of the |
| 108 | * {@link #setIsReaderTransactionalQueue(boolean) transactional queue flag} |
| 109 | * being false (the default). |
| 110 | * |
| 111 | * @param keyGenerator the {@link KeyGenerator} to set |
| 112 | */ |
| 113 | public void setKeyGenerator(KeyGenerator keyGenerator) { |
| 114 | this.keyGenerator = keyGenerator; |
| 115 | } |
| 116 | |
| 117 | /** |
| 118 | * Setter for the retry policy. If this is specified the other retry |
| 119 | * properties are ignored (retryLimit, backOffPolicy, |
| 120 | * retryableExceptionClasses). |
| 121 | * |
| 122 | * @param retryPolicy a stateless {@link RetryPolicy} |
| 123 | */ |
| 124 | public void setRetryPolicy(RetryPolicy retryPolicy) { |
| 125 | this.retryPolicy = retryPolicy; |
| 126 | } |
| 127 | |
| 128 | /** |
| 129 | * Public setter for the retry limit. Each item can be retried up to this |
| 130 | * limit. Note this limit includes the initial attempt to process the item, |
| 131 | * therefore <code>retryLimit == 1</code> by default. |
| 132 | * |
| 133 | * @param retryLimit the retry limit to set, must be greater or equal to 1. |
| 134 | */ |
| 135 | public void setRetryLimit(int retryLimit) { |
| 136 | this.retryLimit = retryLimit; |
| 137 | } |
| 138 | |
| 139 | /** |
| 140 | * Public setter for the capacity of the cache in the retry policy. If more |
| 141 | * items than this fail without being skipped or recovered an exception will |
| 142 | * be thrown. This is to guard against inadvertent infinite loops generated |
| 143 | * by item identity problems.<br/> |
| 144 | * |
| 145 | * The default value should be high enough and more for most purposes. To |
| 146 | * breach the limit in a single-threaded step typically you have to have |
| 147 | * this many failures in a single transaction. Defaults to the value in the |
| 148 | * {@link MapRetryContextCache}.<br/> |
| 149 | * |
| 150 | * This property is ignored if the |
| 151 | * {@link #setRetryContextCache(RetryContextCache)} is set directly. |
| 152 | * |
| 153 | * @param cacheCapacity the cache capacity to set (greater than 0 else |
| 154 | * ignored) |
| 155 | */ |
| 156 | public void setCacheCapacity(int cacheCapacity) { |
| 157 | this.cacheCapacity = cacheCapacity; |
| 158 | } |
| 159 | |
| 160 | /** |
| 161 | * Override the default retry context cache for retry of chunk processing. |
| 162 | * If this property is set then {@link #setCacheCapacity(int)} is ignored. |
| 163 | * |
| 164 | * @param retryContextCache the {@link RetryContextCache} to set |
| 165 | */ |
| 166 | public void setRetryContextCache(RetryContextCache retryContextCache) { |
| 167 | this.retryContextCache = retryContextCache; |
| 168 | } |
| 169 | |
| 170 | /** |
| 171 | * Public setter for the Class[]. |
| 172 | * @param retryableExceptionClasses the retryableExceptionClasses to set |
| 173 | */ |
| 174 | public void setRetryableExceptionClasses(Collection<Class<? extends Throwable>> retryableExceptionClasses) { |
| 175 | this.retryableExceptionClasses = retryableExceptionClasses; |
| 176 | } |
| 177 | |
| 178 | /** |
| 179 | * Public setter for the {@link BackOffPolicy}. |
| 180 | * @param backOffPolicy the {@link BackOffPolicy} to set |
| 181 | */ |
| 182 | public void setBackOffPolicy(BackOffPolicy backOffPolicy) { |
| 183 | this.backOffPolicy = backOffPolicy; |
| 184 | } |
| 185 | |
| 186 | /** |
| 187 | * Public setter for the {@link RetryListener}s. |
| 188 | * @param retryListeners the {@link RetryListener}s to set |
| 189 | */ |
| 190 | public void setRetryListeners(RetryListener... retryListeners) { |
| 191 | this.retryListeners = retryListeners; |
| 192 | } |
| 193 | |
| 194 | /** |
| 195 | * A limit that determines skip policy. If this value is positive then an |
| 196 | * exception in chunk processing will cause the item to be skipped and no |
| 197 | * exception propagated until the limit is reached. If it is zero then all |
| 198 | * exceptions will be propagated from the chunk and cause the step to abort. |
| 199 | * |
| 200 | * @param skipLimit the value to set. Default is 0 (never skip). |
| 201 | */ |
| 202 | public void setSkipLimit(int skipLimit) { |
| 203 | this.skipLimit = skipLimit; |
| 204 | } |
| 205 | |
| 206 | /** |
| 207 | * Exception classes that when raised won't crash the job but will result in |
| 208 | * the item which handling caused the exception being skipped. Any exception |
| 209 | * which is marked for "no rollback" is also skippable, but not vice versa. |
| 210 | * Remember to set the {@link #setSkipLimit(int) skip limit} as well. |
| 211 | * <p/> |
| 212 | * Defaults to all exceptions. |
| 213 | * |
| 214 | * @param exceptionClasses defaults to <code>Exception</code> |
| 215 | */ |
| 216 | public void setSkippableExceptionClasses(Collection<Class<? extends Throwable>> exceptionClasses) { |
| 217 | this.skippableExceptionClasses = exceptionClasses; |
| 218 | } |
| 219 | |
| 220 | /** |
| 221 | * Exception classes that are candidates for no rollback. The {@link Step} |
| 222 | * can not honour the no rollback hint in all circumstances, but any |
| 223 | * exception on this list is counted as skippable, so even if there has to |
| 224 | * be a rollback, then the step will not fail as long as the skip limit is |
| 225 | * not breached. |
| 226 | * <p/> |
| 227 | * Defaults is empty. |
| 228 | * |
| 229 | * @param noRollbackExceptionClasses the exception classes to set |
| 230 | */ |
| 231 | public void setNoRollbackExceptionClasses(Collection<Class<? extends Throwable>> noRollbackExceptionClasses) { |
| 232 | this.noRollbackExceptionClasses = noRollbackExceptionClasses; |
| 233 | } |
| 234 | |
| 235 | /** |
| 236 | * Exception classes that are not skippable (but may be retryable). |
| 237 | * |
| 238 | * @param fatalExceptionClasses {@link Error} by default |
| 239 | */ |
| 240 | public void setFatalExceptionClasses(Collection<Class<? extends Throwable>> fatalExceptionClasses) { |
| 241 | this.fatalExceptionClasses = fatalExceptionClasses; |
| 242 | } |
| 243 | |
| 244 | /** |
| 245 | * Convenience method for subclasses to get an exception classifier based on |
| 246 | * the provided transaction attributes. |
| 247 | * |
| 248 | * @return an exception classifier: maps to true if an exception should |
| 249 | * cause rollback |
| 250 | */ |
| 251 | protected Classifier<Throwable, Boolean> getRollbackClassifier() { |
| 252 | |
| 253 | Classifier<Throwable, Boolean> classifier = new BinaryExceptionClassifier(noRollbackExceptionClasses, false); |
| 254 | |
| 255 | // Try to avoid pathological cases where we cannot force a rollback |
| 256 | // (should be pretty uncommon): |
| 257 | if (!classifier.classify(new ForceRollbackForWriteSkipException("test", new RuntimeException())) |
| 258 | || !classifier.classify(new ExhaustedRetryException("test"))) { |
| 259 | |
| 260 | final Classifier<Throwable, Boolean> binary = classifier; |
| 261 | |
| 262 | Collection<Class<? extends Throwable>> types = new HashSet<Class<? extends Throwable>>(); |
| 263 | types.add(ForceRollbackForWriteSkipException.class); |
| 264 | types.add(ExhaustedRetryException.class); |
| 265 | final Classifier<Throwable, Boolean> panic = new BinaryExceptionClassifier(types, true); |
| 266 | |
| 267 | classifier = new Classifier<Throwable, Boolean>() { |
| 268 | public Boolean classify(Throwable classifiable) { |
| 269 | // Rollback if either the user's list or our own applies |
| 270 | return panic.classify(classifiable) || binary.classify(classifiable); |
| 271 | } |
| 272 | }; |
| 273 | |
| 274 | } |
| 275 | |
| 276 | return classifier; |
| 277 | |
| 278 | } |
| 279 | |
| 280 | /** |
| 281 | * Getter for the {@link TransactionAttribute} for subclasses only. |
| 282 | * @return the transactionAttribute |
| 283 | */ |
| 284 | @Override |
| 285 | protected TransactionAttribute getTransactionAttribute() { |
| 286 | |
| 287 | TransactionAttribute attribute = super.getTransactionAttribute(); |
| 288 | final Classifier<Throwable, Boolean> classifier = getRollbackClassifier(); |
| 289 | return new DefaultTransactionAttribute(attribute) { |
| 290 | @Override |
| 291 | public boolean rollbackOn(Throwable ex) { |
| 292 | return classifier.classify(ex); |
| 293 | } |
| 294 | |
| 295 | }; |
| 296 | |
| 297 | } |
| 298 | |
| 299 | @Override |
| 300 | protected void applyConfiguration(TaskletStep step) { |
| 301 | |
| 302 | addFatalExceptionIfMissing(SkipLimitExceededException.class, NonSkippableReadException.class, |
| 303 | SkipListenerFailedException.class, RetryException.class, JobInterruptedException.class, Error.class); |
| 304 | addNonRetryableExceptionIfMissing(SkipLimitExceededException.class, NonSkippableReadException.class, |
| 305 | SkipListenerFailedException.class, RetryException.class, JobInterruptedException.class, Error.class); |
| 306 | |
| 307 | super.applyConfiguration(step); |
| 308 | |
| 309 | } |
| 310 | |
| 311 | /** |
| 312 | * {@inheritDoc} |
| 313 | */ |
| 314 | @Override |
| 315 | protected void registerStreams(TaskletStep step, ItemStream[] streams) { |
| 316 | boolean streamIsReader = false; |
| 317 | ItemReader<? extends T> itemReader = getItemReader(); |
| 318 | for (ItemStream stream : streams) { |
| 319 | if (stream instanceof ItemReader) { |
| 320 | streamIsReader = true; |
| 321 | chunkMonitor.registerItemStream(stream); |
| 322 | } |
| 323 | else { |
| 324 | step.registerStream(stream); |
| 325 | } |
| 326 | } |
| 327 | TaskExecutor taskExecutor = getTaskExecutor(); |
| 328 | // In cases where multiple nested item readers are registered, |
| 329 | // they all want to get the open() and close() callbacks. |
| 330 | if (streamIsReader) { |
| 331 | // double registration is fine |
| 332 | step.registerStream(chunkMonitor); |
| 333 | boolean concurrent = taskExecutor != null && !(taskExecutor instanceof SyncTaskExecutor); |
| 334 | if (!concurrent) { |
| 335 | chunkMonitor.setItemReader(itemReader); |
| 336 | } |
| 337 | else { |
| 338 | logger.warn("Synchronous TaskExecutor detected (" + taskExecutor.getClass() |
| 339 | + ") with ItemStream reader. This is probably an error, " |
| 340 | + "and may lead to incorrect restart data being stored."); |
| 341 | } |
| 342 | } |
| 343 | } |
| 344 | |
| 345 | /** |
| 346 | * @return {@link ChunkProvider} configured for fault-tolerance. |
| 347 | */ |
| 348 | @Override |
| 349 | protected SimpleChunkProvider<T> configureChunkProvider() { |
| 350 | |
| 351 | SkipPolicy readSkipPolicy = new LimitCheckingItemSkipPolicy(skipLimit, getSkippableExceptionClasses(), |
| 352 | fatalExceptionClasses); |
| 353 | FaultTolerantChunkProvider<T> chunkProvider = new FaultTolerantChunkProvider<T>(getItemReader(), |
| 354 | getChunkOperations()); |
| 355 | chunkProvider.setSkipPolicy(readSkipPolicy); |
| 356 | chunkProvider.setRollbackClassifier(getRollbackClassifier()); |
| 357 | |
| 358 | return chunkProvider; |
| 359 | |
| 360 | } |
| 361 | |
| 362 | /** |
| 363 | * @return {@link ChunkProcessor} configured for fault-tolerance. |
| 364 | */ |
| 365 | @Override |
| 366 | protected SimpleChunkProcessor<T, S> configureChunkProcessor() { |
| 367 | |
| 368 | BatchRetryTemplate batchRetryTemplate = configureRetry(); |
| 369 | |
| 370 | FaultTolerantChunkProcessor<T, S> chunkProcessor = new FaultTolerantChunkProcessor<T, S>(getItemProcessor(), |
| 371 | getItemWriter(), batchRetryTemplate); |
| 372 | chunkProcessor.setBuffering(!isReaderTransactionalQueue()); |
| 373 | |
| 374 | SkipPolicy writeSkipPolicy = new LimitCheckingItemSkipPolicy(skipLimit, getSkippableExceptionClasses(), |
| 375 | fatalExceptionClasses); |
| 376 | chunkProcessor.setWriteSkipPolicy(writeSkipPolicy); |
| 377 | chunkProcessor.setProcessSkipPolicy(writeSkipPolicy); |
| 378 | chunkProcessor.setRollbackClassifier(getRollbackClassifier()); |
| 379 | chunkProcessor.setKeyGenerator(keyGenerator); |
| 380 | chunkProcessor.setChunkMonitor(chunkMonitor); |
| 381 | |
| 382 | return chunkProcessor; |
| 383 | |
| 384 | } |
| 385 | |
| 386 | /** |
| 387 | * @return |
| 388 | */ |
| 389 | private Collection<Class<? extends Throwable>> getSkippableExceptionClasses() { |
| 390 | HashSet<Class<? extends Throwable>> set = new HashSet<Class<? extends Throwable>>(skippableExceptionClasses); |
| 391 | set.add(ForceRollbackForWriteSkipException.class); |
| 392 | return set; |
| 393 | } |
| 394 | |
| 395 | /** |
| 396 | * @return fully configured retry template for item processing phase. |
| 397 | */ |
| 398 | private BatchRetryTemplate configureRetry() { |
| 399 | |
| 400 | if (retryPolicy == null) { |
| 401 | SimpleRetryPolicy simpleRetryPolicy = new SimpleRetryPolicy(retryLimit); |
| 402 | HashSet<Class<? extends Throwable>> set = new HashSet<Class<? extends Throwable>>(retryableExceptionClasses); |
| 403 | set.add(ForceRollbackForWriteSkipException.class); |
| 404 | // set.addAll(noRollbackExceptionClasses); // should only be |
| 405 | // retryable on write |
| 406 | simpleRetryPolicy.setRetryableExceptionClasses(set); |
| 407 | retryPolicy = simpleRetryPolicy; |
| 408 | } |
| 409 | |
| 410 | RetryPolicy retryPolicyWrapper = fatalExceptionAwareProxy(retryPolicy); |
| 411 | |
| 412 | BatchRetryTemplate batchRetryTemplate = new BatchRetryTemplate(); |
| 413 | if (backOffPolicy != null) { |
| 414 | batchRetryTemplate.setBackOffPolicy(backOffPolicy); |
| 415 | } |
| 416 | batchRetryTemplate.setRetryPolicy(retryPolicyWrapper); |
| 417 | |
| 418 | // Co-ordinate the retry policy with the exception handler: |
| 419 | RepeatOperations stepOperations = getStepOperations(); |
| 420 | if (stepOperations instanceof RepeatTemplate) { |
| 421 | SimpleRetryExceptionHandler exceptionHandler = new SimpleRetryExceptionHandler(retryPolicyWrapper, |
| 422 | getExceptionHandler(), nonRetryableExceptionClasses); |
| 423 | ((RepeatTemplate) stepOperations).setExceptionHandler(exceptionHandler); |
| 424 | } |
| 425 | |
| 426 | if (retryContextCache == null) { |
| 427 | if (cacheCapacity > 0) { |
| 428 | batchRetryTemplate.setRetryContextCache(new MapRetryContextCache(cacheCapacity)); |
| 429 | } |
| 430 | } |
| 431 | else { |
| 432 | batchRetryTemplate.setRetryContextCache(retryContextCache); |
| 433 | } |
| 434 | |
| 435 | if (retryListeners != null) { |
| 436 | batchRetryTemplate.setListeners(retryListeners); |
| 437 | } |
| 438 | return batchRetryTemplate; |
| 439 | } |
| 440 | |
| 441 | /** |
| 442 | * Wrap the provided {@link #setRetryPolicy(RetryPolicy)} so that it never |
| 443 | * retries explicitly non-retryable exceptions. |
| 444 | */ |
| 445 | private RetryPolicy fatalExceptionAwareProxy(final RetryPolicy retryPolicy) { |
| 446 | |
| 447 | NeverRetryPolicy neverRetryPolicy = new NeverRetryPolicy(); |
| 448 | Map<Class<? extends Throwable>, RetryPolicy> map = new HashMap<Class<? extends Throwable>, RetryPolicy>(); |
| 449 | for (Class<? extends Throwable> fatal : nonRetryableExceptionClasses) { |
| 450 | map.put(fatal, neverRetryPolicy); |
| 451 | } |
| 452 | |
| 453 | SubclassClassifier<Throwable, RetryPolicy> classifier = new SubclassClassifier<Throwable, RetryPolicy>( |
| 454 | retryPolicy); |
| 455 | classifier.setTypeMap(map); |
| 456 | |
| 457 | ExceptionClassifierRetryPolicy retryPolicyWrapper = new ExceptionClassifierRetryPolicy(); |
| 458 | retryPolicyWrapper.setExceptionClassifier(classifier); |
| 459 | return retryPolicyWrapper; |
| 460 | |
| 461 | } |
| 462 | |
| 463 | @SuppressWarnings("unchecked") |
| 464 | private void addFatalExceptionIfMissing(Class... cls) { |
| 465 | List exceptions = new ArrayList<Class<? extends Throwable>>(); |
| 466 | for (Class exceptionClass : fatalExceptionClasses) { |
| 467 | exceptions.add(exceptionClass); |
| 468 | } |
| 469 | for (Class fatal : cls) { |
| 470 | if (!exceptions.contains(fatal)) { |
| 471 | exceptions.add(fatal); |
| 472 | } |
| 473 | } |
| 474 | fatalExceptionClasses = exceptions; |
| 475 | } |
| 476 | |
| 477 | @SuppressWarnings("unchecked") |
| 478 | private void addNonRetryableExceptionIfMissing(Class... cls) { |
| 479 | List exceptions = new ArrayList<Class<? extends Throwable>>(); |
| 480 | for (Class exceptionClass : nonRetryableExceptionClasses) { |
| 481 | exceptions.add(exceptionClass); |
| 482 | } |
| 483 | for (Class fatal : cls) { |
| 484 | if (!exceptions.contains(fatal)) { |
| 485 | exceptions.add(fatal); |
| 486 | } |
| 487 | } |
| 488 | nonRetryableExceptionClasses = exceptions; |
| 489 | } |
| 490 | |
| 491 | } |