| 1 | /* |
| 2 | * Copyright 2006-2012 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.item.file; |
| 18 | |
| 19 | import java.io.BufferedWriter; |
| 20 | import java.io.File; |
| 21 | import java.io.FileOutputStream; |
| 22 | import java.io.IOException; |
| 23 | import java.io.Writer; |
| 24 | import java.nio.channels.Channels; |
| 25 | import java.nio.channels.FileChannel; |
| 26 | import java.nio.charset.UnsupportedCharsetException; |
| 27 | import java.util.List; |
| 28 | |
| 29 | import org.apache.commons.logging.Log; |
| 30 | import org.apache.commons.logging.LogFactory; |
| 31 | import org.springframework.batch.item.ExecutionContext; |
| 32 | import org.springframework.batch.item.ItemStream; |
| 33 | import org.springframework.batch.item.ItemStreamException; |
| 34 | import org.springframework.batch.item.WriteFailedException; |
| 35 | import org.springframework.batch.item.WriterNotOpenException; |
| 36 | import org.springframework.batch.item.file.transform.LineAggregator; |
| 37 | import org.springframework.batch.item.support.AbstractItemStreamItemWriter; |
| 38 | import org.springframework.batch.item.util.FileUtils; |
| 39 | import org.springframework.batch.support.transaction.TransactionAwareBufferedWriter; |
| 40 | import org.springframework.beans.factory.InitializingBean; |
| 41 | import org.springframework.core.io.Resource; |
| 42 | import org.springframework.util.Assert; |
| 43 | import org.springframework.util.ClassUtils; |
| 44 | |
| 45 | /** |
| 46 | * This class is an item writer that writes data to a file or stream. The writer |
| 47 | * also provides restart. The location of the output file is defined by a |
| 48 | * {@link Resource} and must represent a writable file.<br/> |
| 49 | * |
| 50 | * Uses buffered writer to improve performance.<br/> |
| 51 | * |
| 52 | * The implementation is *not* thread-safe. |
| 53 | * |
| 54 | * @author Waseem Malik |
| 55 | * @author Tomas Slanina |
| 56 | * @author Robert Kasanicky |
| 57 | * @author Dave Syer |
| 58 | * @author Michael Minella |
| 59 | */ |
| 60 | public class FlatFileItemWriter<T> extends AbstractItemStreamItemWriter<T> implements ResourceAwareItemWriterItemStream<T>, |
| 61 | InitializingBean { |
| 62 | |
| 63 | private static final boolean DEFAULT_TRANSACTIONAL = true; |
| 64 | |
| 65 | protected static final Log logger = LogFactory.getLog(FlatFileItemWriter.class); |
| 66 | |
| 67 | private static final String DEFAULT_LINE_SEPARATOR = System.getProperty("line.separator"); |
| 68 | |
| 69 | private static final String WRITTEN_STATISTICS_NAME = "written"; |
| 70 | |
| 71 | private static final String RESTART_DATA_NAME = "current.count"; |
| 72 | |
| 73 | private Resource resource; |
| 74 | |
| 75 | private OutputState state = null; |
| 76 | |
| 77 | private LineAggregator<T> lineAggregator; |
| 78 | |
| 79 | private boolean saveState = true; |
| 80 | |
| 81 | private boolean forceSync = false; |
| 82 | |
| 83 | private boolean shouldDeleteIfExists = true; |
| 84 | |
| 85 | private boolean shouldDeleteIfEmpty = false; |
| 86 | |
| 87 | private String encoding = OutputState.DEFAULT_CHARSET; |
| 88 | |
| 89 | private FlatFileHeaderCallback headerCallback; |
| 90 | |
| 91 | private FlatFileFooterCallback footerCallback; |
| 92 | |
| 93 | private String lineSeparator = DEFAULT_LINE_SEPARATOR; |
| 94 | |
| 95 | private boolean transactional = DEFAULT_TRANSACTIONAL; |
| 96 | |
| 97 | private boolean append = false; |
| 98 | |
| 99 | public FlatFileItemWriter() { |
| 100 | this.setExecutionContextName(ClassUtils.getShortName(FlatFileItemWriter.class)); |
| 101 | } |
| 102 | |
| 103 | /** |
| 104 | * Assert that mandatory properties (lineAggregator) are set. |
| 105 | * |
| 106 | * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet() |
| 107 | */ |
| 108 | @Override |
| 109 | public void afterPropertiesSet() throws Exception { |
| 110 | Assert.notNull(lineAggregator, "A LineAggregator must be provided."); |
| 111 | if (append) { |
| 112 | shouldDeleteIfExists = false; |
| 113 | } |
| 114 | } |
| 115 | |
| 116 | /** |
| 117 | * Flag to indicate that changes should be force-synced to disk on flush. |
| 118 | * Defaults to false, which means that even with a local disk changes could |
| 119 | * be lost if the OS crashes in between a write and a cache flush. Setting |
| 120 | * to true may result in slower performance for usage patterns involving many |
| 121 | * frequent writes. |
| 122 | * |
| 123 | * @param forceSync the flag value to set |
| 124 | */ |
| 125 | public void setForceSync(boolean forceSync) { |
| 126 | this.forceSync = forceSync; |
| 127 | } |
| 128 | |
| 129 | /** |
| 130 | * Public setter for the line separator. Defaults to the System property |
| 131 | * line.separator. |
| 132 | * @param lineSeparator the line separator to set |
| 133 | */ |
| 134 | public void setLineSeparator(String lineSeparator) { |
| 135 | this.lineSeparator = lineSeparator; |
| 136 | } |
| 137 | |
| 138 | /** |
| 139 | * Public setter for the {@link LineAggregator}. This will be used to |
| 140 | * translate the item into a line for output. |
| 141 | * |
| 142 | * @param lineAggregator the {@link LineAggregator} to set |
| 143 | */ |
| 144 | public void setLineAggregator(LineAggregator<T> lineAggregator) { |
| 145 | this.lineAggregator = lineAggregator; |
| 146 | } |
| 147 | |
| 148 | /** |
| 149 | * Setter for resource. Represents a file that can be written. |
| 150 | * |
| 151 | * @param resource |
| 152 | */ |
| 153 | @Override |
| 154 | public void setResource(Resource resource) { |
| 155 | this.resource = resource; |
| 156 | } |
| 157 | |
| 158 | /** |
| 159 | * Sets encoding for output template. |
| 160 | */ |
| 161 | public void setEncoding(String newEncoding) { |
| 162 | this.encoding = newEncoding; |
| 163 | } |
| 164 | |
| 165 | /** |
| 166 | * Flag to indicate that the target file should be deleted if it already |
| 167 | * exists, otherwise it will be created. Defaults to true, so no appending |
| 168 | * except on restart. If set to false and {@link #setAppendAllowed(boolean) |
| 169 | * appendAllowed} is also false then there will be an exception when the |
| 170 | * stream is opened to prevent existing data being potentially corrupted. |
| 171 | * |
| 172 | * @param shouldDeleteIfExists the flag value to set |
| 173 | */ |
| 174 | public void setShouldDeleteIfExists(boolean shouldDeleteIfExists) { |
| 175 | this.shouldDeleteIfExists = shouldDeleteIfExists; |
| 176 | } |
| 177 | |
| 178 | /** |
| 179 | * Flag to indicate that the target file should be appended if it already |
| 180 | * exists. If this flag is set then the flag |
| 181 | * {@link #setShouldDeleteIfExists(boolean) shouldDeleteIfExists} is |
| 182 | * automatically set to false, so that flag should not be set explicitly. |
| 183 | * Defaults value is false. |
| 184 | * |
| 185 | * @param append the flag value to set |
| 186 | */ |
| 187 | public void setAppendAllowed(boolean append) { |
| 188 | this.append = append; |
| 189 | this.shouldDeleteIfExists = false; |
| 190 | } |
| 191 | |
| 192 | /** |
| 193 | * Flag to indicate that the target file should be deleted if no lines have |
| 194 | * been written (other than header and footer) on close. Defaults to false. |
| 195 | * |
| 196 | * @param shouldDeleteIfEmpty the flag value to set |
| 197 | */ |
| 198 | public void setShouldDeleteIfEmpty(boolean shouldDeleteIfEmpty) { |
| 199 | this.shouldDeleteIfEmpty = shouldDeleteIfEmpty; |
| 200 | } |
| 201 | |
| 202 | /** |
| 203 | * Set the flag indicating whether or not state should be saved in the |
| 204 | * provided {@link ExecutionContext} during the {@link ItemStream} call to |
| 205 | * update. Setting this to false means that it will always start at the |
| 206 | * beginning on a restart. |
| 207 | * |
| 208 | * @param saveState |
| 209 | */ |
| 210 | public void setSaveState(boolean saveState) { |
| 211 | this.saveState = saveState; |
| 212 | } |
| 213 | |
| 214 | /** |
| 215 | * headerCallback will be called before writing the first item to file. |
| 216 | * Newline will be automatically appended after the header is written. |
| 217 | */ |
| 218 | public void setHeaderCallback(FlatFileHeaderCallback headerCallback) { |
| 219 | this.headerCallback = headerCallback; |
| 220 | } |
| 221 | |
| 222 | /** |
| 223 | * footerCallback will be called after writing the last item to file, but |
| 224 | * before the file is closed. |
| 225 | */ |
| 226 | public void setFooterCallback(FlatFileFooterCallback footerCallback) { |
| 227 | this.footerCallback = footerCallback; |
| 228 | } |
| 229 | |
| 230 | /** |
| 231 | * Flag to indicate that writing to the buffer should be delayed if a |
| 232 | * transaction is active. Defaults to true. |
| 233 | */ |
| 234 | public void setTransactional(boolean transactional) { |
| 235 | this.transactional = transactional; |
| 236 | } |
| 237 | |
| 238 | /** |
| 239 | * Writes out a string followed by a "new line", where the format of the new |
| 240 | * line separator is determined by the underlying operating system. If the |
| 241 | * input is not a String and a converter is available the converter will be |
| 242 | * applied and then this method recursively called with the result. If the |
| 243 | * input is an array or collection each value will be written to a separate |
| 244 | * line (recursively calling this method for each value). If no converter is |
| 245 | * supplied the input object's toString method will be used.<br/> |
| 246 | * |
| 247 | * @param items list of items to be written to output stream |
| 248 | * @throws Exception if the transformer or file output fail, |
| 249 | * WriterNotOpenException if the writer has not been initialized. |
| 250 | */ |
| 251 | @Override |
| 252 | public void write(List<? extends T> items) throws Exception { |
| 253 | |
| 254 | if (!getOutputState().isInitialized()) { |
| 255 | throw new WriterNotOpenException("Writer must be open before it can be written to"); |
| 256 | } |
| 257 | |
| 258 | if (logger.isDebugEnabled()) { |
| 259 | logger.debug("Writing to flat file with " + items.size() + " items."); |
| 260 | } |
| 261 | |
| 262 | OutputState state = getOutputState(); |
| 263 | |
| 264 | StringBuilder lines = new StringBuilder(); |
| 265 | int lineCount = 0; |
| 266 | for (T item : items) { |
| 267 | lines.append(lineAggregator.aggregate(item) + lineSeparator); |
| 268 | lineCount++; |
| 269 | } |
| 270 | try { |
| 271 | state.write(lines.toString()); |
| 272 | } |
| 273 | catch (IOException e) { |
| 274 | throw new WriteFailedException("Could not write data. The file may be corrupt.", e); |
| 275 | } |
| 276 | state.linesWritten += lineCount; |
| 277 | } |
| 278 | |
| 279 | /** |
| 280 | * @see ItemStream#close() |
| 281 | */ |
| 282 | @Override |
| 283 | public void close() { |
| 284 | super.close(); |
| 285 | if (state != null) { |
| 286 | try { |
| 287 | if (footerCallback != null && state.outputBufferedWriter != null) { |
| 288 | footerCallback.writeFooter(state.outputBufferedWriter); |
| 289 | state.outputBufferedWriter.flush(); |
| 290 | } |
| 291 | } |
| 292 | catch (IOException e) { |
| 293 | throw new ItemStreamException("Failed to write footer before closing", e); |
| 294 | } |
| 295 | finally { |
| 296 | state.close(); |
| 297 | if (state.linesWritten == 0 && shouldDeleteIfEmpty) { |
| 298 | try { |
| 299 | resource.getFile().delete(); |
| 300 | } |
| 301 | catch (IOException e) { |
| 302 | throw new ItemStreamException("Failed to delete empty file on close", e); |
| 303 | } |
| 304 | } |
| 305 | state = null; |
| 306 | } |
| 307 | } |
| 308 | } |
| 309 | |
| 310 | /** |
| 311 | * Initialize the reader. This method may be called multiple times before |
| 312 | * close is called. |
| 313 | * |
| 314 | * @see ItemStream#open(ExecutionContext) |
| 315 | */ |
| 316 | @Override |
| 317 | public void open(ExecutionContext executionContext) throws ItemStreamException { |
| 318 | super.open(executionContext); |
| 319 | |
| 320 | Assert.notNull(resource, "The resource must be set"); |
| 321 | |
| 322 | if (!getOutputState().isInitialized()) { |
| 323 | doOpen(executionContext); |
| 324 | } |
| 325 | } |
| 326 | |
| 327 | private void doOpen(ExecutionContext executionContext) throws ItemStreamException { |
| 328 | OutputState outputState = getOutputState(); |
| 329 | if (executionContext.containsKey(getExecutionContextKey(RESTART_DATA_NAME))) { |
| 330 | outputState.restoreFrom(executionContext); |
| 331 | } |
| 332 | try { |
| 333 | outputState.initializeBufferedWriter(); |
| 334 | } |
| 335 | catch (IOException ioe) { |
| 336 | throw new ItemStreamException("Failed to initialize writer", ioe); |
| 337 | } |
| 338 | if (outputState.lastMarkedByteOffsetPosition == 0 && !outputState.appending) { |
| 339 | if (headerCallback != null) { |
| 340 | try { |
| 341 | headerCallback.writeHeader(outputState.outputBufferedWriter); |
| 342 | outputState.write(lineSeparator); |
| 343 | } |
| 344 | catch (IOException e) { |
| 345 | throw new ItemStreamException("Could not write headers. The file may be corrupt.", e); |
| 346 | } |
| 347 | } |
| 348 | } |
| 349 | } |
| 350 | |
| 351 | /** |
| 352 | * @see ItemStream#update(ExecutionContext) |
| 353 | */ |
| 354 | @Override |
| 355 | public void update(ExecutionContext executionContext) { |
| 356 | super.update(executionContext); |
| 357 | if (state == null) { |
| 358 | throw new ItemStreamException("ItemStream not open or already closed."); |
| 359 | } |
| 360 | |
| 361 | Assert.notNull(executionContext, "ExecutionContext must not be null"); |
| 362 | |
| 363 | if (saveState) { |
| 364 | |
| 365 | try { |
| 366 | executionContext.putLong(getExecutionContextKey(RESTART_DATA_NAME), state.position()); |
| 367 | } |
| 368 | catch (IOException e) { |
| 369 | throw new ItemStreamException("ItemStream does not return current position properly", e); |
| 370 | } |
| 371 | |
| 372 | executionContext.putLong(getExecutionContextKey(WRITTEN_STATISTICS_NAME), state.linesWritten); |
| 373 | } |
| 374 | } |
| 375 | |
| 376 | // Returns object representing state. |
| 377 | private OutputState getOutputState() { |
| 378 | if (state == null) { |
| 379 | File file; |
| 380 | try { |
| 381 | file = resource.getFile(); |
| 382 | } |
| 383 | catch (IOException e) { |
| 384 | throw new ItemStreamException("Could not convert resource to file: [" + resource + "]", e); |
| 385 | } |
| 386 | Assert.state(!file.exists() || file.canWrite(), "Resource is not writable: [" + resource + "]"); |
| 387 | state = new OutputState(); |
| 388 | state.setDeleteIfExists(shouldDeleteIfExists); |
| 389 | state.setAppendAllowed(append); |
| 390 | state.setEncoding(encoding); |
| 391 | } |
| 392 | return state; |
| 393 | } |
| 394 | |
| 395 | /** |
| 396 | * Encapsulates the runtime state of the writer. All state changing |
| 397 | * operations on the writer go through this class. |
| 398 | */ |
| 399 | private class OutputState { |
| 400 | // default encoding for writing to output files - set to UTF-8. |
| 401 | private static final String DEFAULT_CHARSET = "UTF-8"; |
| 402 | |
| 403 | private FileOutputStream os; |
| 404 | |
| 405 | // The bufferedWriter over the file channel that is actually written |
| 406 | Writer outputBufferedWriter; |
| 407 | |
| 408 | FileChannel fileChannel; |
| 409 | |
| 410 | // this represents the charset encoding (if any is needed) for the |
| 411 | // output file |
| 412 | String encoding = DEFAULT_CHARSET; |
| 413 | |
| 414 | boolean restarted = false; |
| 415 | |
| 416 | long lastMarkedByteOffsetPosition = 0; |
| 417 | |
| 418 | long linesWritten = 0; |
| 419 | |
| 420 | boolean shouldDeleteIfExists = true; |
| 421 | |
| 422 | boolean initialized = false; |
| 423 | |
| 424 | private boolean append = false; |
| 425 | |
| 426 | private boolean appending = false; |
| 427 | |
| 428 | /** |
| 429 | * Return the byte offset position of the cursor in the output file as a |
| 430 | * long integer. |
| 431 | */ |
| 432 | public long position() throws IOException { |
| 433 | long pos = 0; |
| 434 | |
| 435 | if (fileChannel == null) { |
| 436 | return 0; |
| 437 | } |
| 438 | |
| 439 | outputBufferedWriter.flush(); |
| 440 | pos = fileChannel.position(); |
| 441 | if (transactional) { |
| 442 | pos += ((TransactionAwareBufferedWriter) outputBufferedWriter).getBufferSize(); |
| 443 | } |
| 444 | |
| 445 | return pos; |
| 446 | |
| 447 | } |
| 448 | |
| 449 | /** |
| 450 | * @param append |
| 451 | */ |
| 452 | public void setAppendAllowed(boolean append) { |
| 453 | this.append = append; |
| 454 | } |
| 455 | |
| 456 | /** |
| 457 | * @param executionContext |
| 458 | */ |
| 459 | public void restoreFrom(ExecutionContext executionContext) { |
| 460 | lastMarkedByteOffsetPosition = executionContext.getLong(getExecutionContextKey(RESTART_DATA_NAME)); |
| 461 | linesWritten = executionContext.getLong(getExecutionContextKey(WRITTEN_STATISTICS_NAME)); |
| 462 | if (shouldDeleteIfEmpty && linesWritten == 0) { |
| 463 | // previous execution deleted the output file because no items were written |
| 464 | restarted = false; |
| 465 | lastMarkedByteOffsetPosition = 0; |
| 466 | } else { |
| 467 | restarted = true; |
| 468 | } |
| 469 | } |
| 470 | |
| 471 | /** |
| 472 | * @param shouldDeleteIfExists |
| 473 | */ |
| 474 | public void setDeleteIfExists(boolean shouldDeleteIfExists) { |
| 475 | this.shouldDeleteIfExists = shouldDeleteIfExists; |
| 476 | } |
| 477 | |
| 478 | /** |
| 479 | * @param encoding |
| 480 | */ |
| 481 | public void setEncoding(String encoding) { |
| 482 | this.encoding = encoding; |
| 483 | } |
| 484 | |
| 485 | /** |
| 486 | * Close the open resource and reset counters. |
| 487 | */ |
| 488 | public void close() { |
| 489 | |
| 490 | initialized = false; |
| 491 | restarted = false; |
| 492 | try { |
| 493 | if (outputBufferedWriter != null) { |
| 494 | outputBufferedWriter.close(); |
| 495 | } |
| 496 | } |
| 497 | catch (IOException ioe) { |
| 498 | throw new ItemStreamException("Unable to close the the ItemWriter", ioe); |
| 499 | } |
| 500 | finally { |
| 501 | if (!transactional) { |
| 502 | closeStream(); |
| 503 | } |
| 504 | } |
| 505 | } |
| 506 | |
| 507 | private void closeStream() { |
| 508 | try { |
| 509 | if (fileChannel != null) { |
| 510 | fileChannel.close(); |
| 511 | } |
| 512 | } |
| 513 | catch (IOException ioe) { |
| 514 | throw new ItemStreamException("Unable to close the the ItemWriter", ioe); |
| 515 | } |
| 516 | finally { |
| 517 | try { |
| 518 | if (os != null) { |
| 519 | os.close(); |
| 520 | } |
| 521 | } |
| 522 | catch (IOException ioe) { |
| 523 | throw new ItemStreamException("Unable to close the the ItemWriter", ioe); |
| 524 | } |
| 525 | } |
| 526 | } |
| 527 | |
| 528 | /** |
| 529 | * @param line |
| 530 | * @throws IOException |
| 531 | */ |
| 532 | public void write(String line) throws IOException { |
| 533 | if (!initialized) { |
| 534 | initializeBufferedWriter(); |
| 535 | } |
| 536 | |
| 537 | outputBufferedWriter.write(line); |
| 538 | outputBufferedWriter.flush(); |
| 539 | } |
| 540 | |
| 541 | /** |
| 542 | * Truncate the output at the last known good point. |
| 543 | * |
| 544 | * @throws IOException |
| 545 | */ |
| 546 | public void truncate() throws IOException { |
| 547 | fileChannel.truncate(lastMarkedByteOffsetPosition); |
| 548 | fileChannel.position(lastMarkedByteOffsetPosition); |
| 549 | } |
| 550 | |
| 551 | /** |
| 552 | * Creates the buffered writer for the output file channel based on |
| 553 | * configuration information. |
| 554 | * @throws IOException |
| 555 | */ |
| 556 | private void initializeBufferedWriter() throws IOException { |
| 557 | |
| 558 | File file = resource.getFile(); |
| 559 | FileUtils.setUpOutputFile(file, restarted, append, shouldDeleteIfExists); |
| 560 | |
| 561 | os = new FileOutputStream(file.getAbsolutePath(), true); |
| 562 | fileChannel = os.getChannel(); |
| 563 | |
| 564 | outputBufferedWriter = getBufferedWriter(fileChannel, encoding); |
| 565 | outputBufferedWriter.flush(); |
| 566 | |
| 567 | if (append) { |
| 568 | // Bug in IO library? This doesn't work... |
| 569 | // lastMarkedByteOffsetPosition = fileChannel.position(); |
| 570 | if (file.length() > 0) { |
| 571 | appending = true; |
| 572 | // Don't write the headers again |
| 573 | } |
| 574 | } |
| 575 | |
| 576 | Assert.state(outputBufferedWriter != null); |
| 577 | // in case of restarting reset position to last committed point |
| 578 | if (restarted) { |
| 579 | checkFileSize(); |
| 580 | truncate(); |
| 581 | } |
| 582 | |
| 583 | initialized = true; |
| 584 | } |
| 585 | |
| 586 | public boolean isInitialized() { |
| 587 | return initialized; |
| 588 | } |
| 589 | |
| 590 | /** |
| 591 | * Returns the buffered writer opened to the beginning of the file |
| 592 | * specified by the absolute path name contained in absoluteFileName. |
| 593 | */ |
| 594 | private Writer getBufferedWriter(FileChannel fileChannel, String encoding) { |
| 595 | try { |
| 596 | final FileChannel channel = fileChannel; |
| 597 | if (transactional) { |
| 598 | TransactionAwareBufferedWriter writer = new TransactionAwareBufferedWriter(channel, new Runnable() { |
| 599 | @Override |
| 600 | public void run() { |
| 601 | closeStream(); |
| 602 | } |
| 603 | }); |
| 604 | |
| 605 | writer.setEncoding(encoding); |
| 606 | writer.setForceSync(forceSync); |
| 607 | return writer; |
| 608 | } |
| 609 | else { |
| 610 | Writer writer = new BufferedWriter(Channels.newWriter(fileChannel, encoding)) { |
| 611 | @Override |
| 612 | public void flush() throws IOException { |
| 613 | super.flush(); |
| 614 | if (forceSync) { |
| 615 | channel.force(false); |
| 616 | } |
| 617 | } |
| 618 | }; |
| 619 | |
| 620 | return writer; |
| 621 | } |
| 622 | } |
| 623 | catch (UnsupportedCharsetException ucse) { |
| 624 | throw new ItemStreamException("Bad encoding configuration for output file " + fileChannel, ucse); |
| 625 | } |
| 626 | } |
| 627 | |
| 628 | /** |
| 629 | * Checks (on setState) to make sure that the current output file's size |
| 630 | * is not smaller than the last saved commit point. If it is, then the |
| 631 | * file has been damaged in some way and whole task must be started over |
| 632 | * again from the beginning. |
| 633 | * @throws IOException if there is an IO problem |
| 634 | */ |
| 635 | private void checkFileSize() throws IOException { |
| 636 | long size = -1; |
| 637 | |
| 638 | outputBufferedWriter.flush(); |
| 639 | size = fileChannel.size(); |
| 640 | |
| 641 | if (size < lastMarkedByteOffsetPosition) { |
| 642 | throw new ItemStreamException("Current file size is smaller than size at last commit"); |
| 643 | } |
| 644 | } |
| 645 | |
| 646 | } |
| 647 | |
| 648 | } |