org.apache.hadoop.io.compress.CompressionCodec Java Examples

public Compressor getCompressor() throws IOException {
  CompressionCodec codec = getCodec();
  if (codec != null) {
    Compressor compressor = CodecPool.getCompressor(codec);
    if (compressor != null) {
      if (compressor.finished()) {
        // Somebody returns the compressor to CodecPool but is still using
        // it.
        LOG.warn("Compressor obtained from CodecPool already finished()");
      } else {
        if(LOG.isDebugEnabled()) {
          LOG.debug("Got a compressor: " + compressor.hashCode());
        }
      }
      /**
       * Following statement is necessary to get around bugs in 0.18 where a
       * compressor is referenced after returned back to the codec pool.
       */
      compressor.reset();
    }
    return compressor;
  }
  return null;
}
 

public static Class<? extends CompressionCodec> getIntermediateOutputCompressorClass(
    Configuration conf, Class<DefaultCodec> defaultValue) {
  Class<? extends CompressionCodec> codecClass = defaultValue;
  String name = conf
      .get(TezJobConfig.TEZ_RUNTIME_COMPRESS_CODEC);
  if (name != null) {
    try {
      codecClass = conf.getClassByName(name).asSubclass(
          CompressionCodec.class);
    } catch (ClassNotFoundException e) {
      throw new IllegalArgumentException("Compression codec " + name
          + " was not found.", e);
    }
  }
  return codecClass;
}
 

@Override // Mapper
public void configure(JobConf conf) {
  super.configure(conf);

  // grab compression
  String compression = getConf().get("test.io.compression.class", null);
  Class<? extends CompressionCodec> codec;

  // try to initialize codec
  try {
    codec = (compression == null) ? null : 
      Class.forName(compression).asSubclass(CompressionCodec.class);
  } catch(Exception e) {
    throw new RuntimeException("Compression codec not found: ", e);
  }

  if(codec != null) {
    compressionCodec = (CompressionCodec)
        ReflectionUtils.newInstance(codec, getConf());
  }
}
 

/**
 * Get the {@link CompressionCodec} for compressing the job outputs.
 * @param job the {@link Job} to look in
 * @param defaultValue the {@link CompressionCodec} to return if not set
 * @return the {@link CompressionCodec} to be used to compress the 
 *         job outputs
 * @throws IllegalArgumentException if the class was specified, but not found
 */
public static Class<? extends CompressionCodec> 
getOutputCompressorClass(JobContext job, 
                       Class<? extends CompressionCodec> defaultValue) {
  Class<? extends CompressionCodec> codecClass = defaultValue;
  Configuration conf = job.getConfiguration();
  String name = conf.get("mapred.output.compression.codec");
  if (name != null) {
    try {
      codecClass = 
      	conf.getClassByName(name).asSubclass(CompressionCodec.class);
    } catch (ClassNotFoundException e) {
      throw new IllegalArgumentException("Compression codec " + name + 
                                         " was not found.", e);
    }
  }
  return codecClass;
}
 

@Test
 public void readBitcoinRawBlockInputFormatGzipCompressed() throws IOException, InterruptedException {
  Configuration conf = new Configuration(defaultConf);
   Job job = Job.getInstance(conf);
   CompressionCodec gzip = new GzipCodec();
   ReflectionUtils.setConf(gzip, conf);
   ClassLoader classLoader = getClass().getClassLoader();
   String fileName="version4comp.blk.gz";
   String fileNameBlock=classLoader.getResource("testdata/"+fileName).getFile();	
   Path file = new Path(fileNameBlock);
   FileInputFormat.setInputPaths(job, file);
   BitcoinRawBlockFileInputFormat format = new BitcoinRawBlockFileInputFormat();
   List<InputSplit> splits = format.getSplits(job);
   TaskAttemptContext context = new TaskAttemptContextImpl(conf, new TaskAttemptID());
   assertEquals( 1, splits.size(),"Only one split generated for compressed block");
   	RecordReader<BytesWritable, BytesWritable> reader = format.createRecordReader(splits.get(0), context);
assertNotNull( reader,"Format returned  null RecordReader");
reader.initialize(splits.get(0),context);
BytesWritable key = new BytesWritable();	
BytesWritable block = new BytesWritable();
assertTrue( reader.nextKeyValue(),"Input Split for block version contains at least one block");
block=reader.getCurrentValue();
assertEquals( 998039, block.getLength(),"Compressed block must have a size of 998.039 bytes");
   	assertFalse( reader.nextKeyValue(),"No further blocks in compressed block");
reader.close();
 }
 

public static <K extends Object, V extends Object>
  TezRawKeyValueIterator merge(Configuration conf, FileSystem fs,
                          Class keyClass, Class valueClass,
                          CompressionCodec codec,
                          List<Segment> segments,
                          int mergeFactor, int inMemSegments, Path tmpDir,
                          RawComparator comparator, Progressable reporter,
                          boolean sortSegments,
                          TezCounter readsCounter,
                          TezCounter writesCounter,
                          TezCounter bytesReadCounter,
                          Progress mergePhase)
    throws IOException {
  return new MergeQueue(conf, fs, segments, comparator, reporter,
                         sortSegments, codec, false).merge(keyClass, valueClass,
                                             mergeFactor, inMemSegments,
                                             tmpDir,
                                             readsCounter, writesCounter,
                                             bytesReadCounter,
                                             mergePhase);
}
 

public static <K extends Object, V extends Object>
RawKeyValueIterator merge(Configuration conf, FileSystem fs,
                          Class<K> keyClass, Class<V> valueClass, 
                          CompressionCodec codec,
                          Path[] inputs, boolean deleteInputs, 
                          int mergeFactor, Path tmpDir,
                          RawComparator<K> comparator, Progressable reporter,
                          Counters.Counter readsCounter,
                          Counters.Counter writesCounter,
                          Progress mergePhase)
throws IOException {
  return 
    new MergeQueue<K, V>(conf, fs, inputs, deleteInputs, codec, comparator, 
                         reporter, null,
                         TaskType.REDUCE).merge(keyClass, valueClass,
                                         mergeFactor, tmpDir,
                                         readsCounter, writesCounter, 
                                         mergePhase);
}
 

/**
 * Get the {@link CompressionCodec} for compressing the job outputs.
 * @param job the {@link Job} to look in
 * @param defaultValue the {@link CompressionCodec} to return if not set
 * @return the {@link CompressionCodec} to be used to compress the 
 *         job outputs
 * @throws IllegalArgumentException if the class was specified, but not found
 */
public static Class<? extends CompressionCodec> 
getOutputCompressorClass(JobContext job, 
                       Class<? extends CompressionCodec> defaultValue) {
  Class<? extends CompressionCodec> codecClass = defaultValue;
  Configuration conf = job.getConfiguration();
  String name = conf.get(FileOutputFormat.COMPRESS_CODEC);
  if (name != null) {
    try {
      codecClass = 
      	conf.getClassByName(name).asSubclass(CompressionCodec.class);
    } catch (ClassNotFoundException e) {
      throw new IllegalArgumentException("Compression codec " + name + 
                                         " was not found.", e);
    }
  }
  return codecClass;
}
 

/**
 * Returns a {@link OutputStream} for a file that might need 
 * compression.
 */
static OutputStream getPossiblyCompressedOutputStream(Path file, 
                                                      Configuration conf)
throws IOException {
  FileSystem fs = file.getFileSystem(conf);
  JobConf jConf = new JobConf(conf);
  if (org.apache.hadoop.mapred.FileOutputFormat.getCompressOutput(jConf)) {
    // get the codec class
    Class<? extends CompressionCodec> codecClass =
      org.apache.hadoop.mapred.FileOutputFormat
                              .getOutputCompressorClass(jConf, 
                                                        GzipCodec.class);
    // get the codec implementation
    CompressionCodec codec = ReflectionUtils.newInstance(codecClass, conf);

    // add the appropriate extension
    file = file.suffix(codec.getDefaultExtension());

    if (isCompressionEmulationEnabled(conf)) {
      FSDataOutputStream fileOut = fs.create(file, false);
      return new DataOutputStream(codec.createOutputStream(fileOut));
    }
  }
  return fs.create(file, false);
}
 

public InMemoryMapOutput(Configuration conf, TaskAttemptID mapId,
                         MergeManagerImpl<K, V> merger,
                         int size, CompressionCodec codec,
                         boolean primaryMapOutput) {
  super(mapId, (long)size, primaryMapOutput);
  this.conf = conf;
  this.merger = merger;
  this.codec = codec;
  byteStream = new BoundedByteArrayOutputStream(size);
  memory = byteStream.getBuffer();
  if (codec != null) {
    decompressor = CodecPool.getDecompressor(codec);
  } else {
    decompressor = null;
  }
}
 

public static <K extends Object, V extends Object>
RawKeyValueIterator merge(Configuration conf, FileSystem fs,
                          Class<K> keyClass, Class<V> valueClass,
                          CompressionCodec codec,
                          List<Segment<K, V>> segments,
                          int mergeFactor, Path tmpDir,
                          RawComparator<K> comparator, Progressable reporter,
                          boolean sortSegments,
                          Counters.Counter readsCounter,
                          Counters.Counter writesCounter,
                          Progress mergePhase,
                          TaskType taskType)
    throws IOException {
  return new MergeQueue<K, V>(conf, fs, segments, comparator, reporter,
                         sortSegments, codec,
                         taskType).merge(keyClass, valueClass,
                                             mergeFactor, tmpDir,
                                             readsCounter, writesCounter,
                                             mergePhase);
}
 

/** Create the named file with write-progress reporter. */
public BlockCompressWriter(FileSystem fs, Configuration conf, Path name,
                           Class keyClass, Class valClass,
                           int bufferSize, short replication, long blockSize,
                           CompressionCodec codec,
                           Progressable progress, Metadata metadata)
  throws IOException {
  super.init(name, conf,
             fs.create(name, true, bufferSize, replication, blockSize, progress),
             keyClass, valClass, true, codec, metadata);
  init(conf.getInt("io.seqfile.compress.blocksize", 1000000));

  initializeFileHeader();
  writeFileHeader();
  finalizeFileHeader();
}
 

/**
 * Construct the preferred type of 'raw' SequenceFile Writer.
 * @param out The stream on top which the writer is to be constructed.
 * @param keyClass The 'key' type.
 * @param valClass The 'value' type.
 * @param compress Compress data?
 * @param blockCompress Compress blocks?
 * @param metadata The metadata of the file.
 * @return Returns the handle to the constructed SequenceFile Writer.
 * @throws IOException
 */
private static Writer
  createWriter(Configuration conf, FSDataOutputStream out, 
               Class keyClass, Class valClass, boolean compress, boolean blockCompress,
               CompressionCodec codec, Metadata metadata)
  throws IOException {
  if (codec != null && (codec instanceof GzipCodec) && 
      !NativeCodeLoader.isNativeCodeLoaded() && 
      !ZlibFactory.isNativeZlibLoaded(conf)) {
    throw new IllegalArgumentException("SequenceFile doesn't work with " +
                                       "GzipCodec without native-hadoop code!");
  }

  Writer writer = null;

  if (!compress) {
    writer = new Writer(conf, out, keyClass, valClass, metadata);
  } else if (compress && !blockCompress) {
    writer = new RecordCompressWriter(conf, out, keyClass, valClass, codec, metadata);
  } else {
    writer = new BlockCompressWriter(conf, out, keyClass, valClass, codec, metadata);
  }
  
  return writer;
}
 

@Test
 public void readBitcoinRawBlockInputFormatBzip2Compressed() throws IOException, InterruptedException {
Configuration conf = new Configuration(defaultConf);
   Job job = Job.getInstance(conf);
   CompressionCodec bzip2 = new BZip2Codec();
   ReflectionUtils.setConf(bzip2, conf);
   ClassLoader classLoader = getClass().getClassLoader();
   String fileName="version4comp.blk.bz2";
   String fileNameBlock=classLoader.getResource("testdata/"+fileName).getFile();	
   Path file = new Path(fileNameBlock);
   FileInputFormat.setInputPaths(job, file);
   BitcoinRawBlockFileInputFormat format = new BitcoinRawBlockFileInputFormat();
   List<InputSplit> splits = format.getSplits(job);
   TaskAttemptContext context = new TaskAttemptContextImpl(conf, new TaskAttemptID());
   assertEquals( 1, splits.size(),"Only one split generated for compressed block");
   	RecordReader<BytesWritable, BytesWritable> reader = format.createRecordReader(splits.get(0), context);
assertNotNull( reader,"Format returned  null RecordReader");
reader.initialize(splits.get(0),context);
BytesWritable key = new BytesWritable();	
BytesWritable block = new BytesWritable();
assertTrue( reader.nextKeyValue(),"Input Split for block version contains at least one block");
block=reader.getCurrentValue();
assertEquals( 998039, block.getLength(),"Compressed block must have a size of 998.039 bytes");
   	assertFalse( reader.nextKeyValue(),"No further blocks in compressed block");
reader.close();
 }
 

private Writer writeTestFile(IFile.Writer writer, boolean rle, boolean repeatKeys,
    List<KVPair> data, CompressionCodec codec) throws IOException {
  assertNotNull(writer);

  Text previousKey = null;
  for (KVPair kvp : data) {
    if (repeatKeys && (previousKey != null && previousKey.compareTo(kvp.getKey()) == 0)) {
      //RLE is enabled in IFile when IFile.REPEAT_KEY is set
      writer.append(IFile.REPEAT_KEY, kvp.getvalue());
    } else {
      writer.append(kvp.getKey(), kvp.getvalue());
    }
    previousKey = kvp.getKey();
  }

  writer.close();

  LOG.info("Uncompressed: " + writer.getRawLength());
  LOG.info("CompressedSize: " + writer.getCompressedLength());

  return writer;
}
 

public Compressor getCompressor() throws IOException {
  CompressionCodec codec = getCodec();
  if (codec != null) {
    Compressor compressor = CodecPool.getCompressor(codec);
    if (compressor != null) {
      if (compressor.finished()) {
        // Somebody returns the compressor to CodecPool but is still using
        // it.
        LOG.warn("Compressor obtained from CodecPool already finished()");
      } else {
        LOG.debug("Got a compressor: " + compressor.hashCode());
      }
      /**
       * Following statement is necessary to get around bugs in 0.18 where a
       * compressor is referenced after returned back to the codec pool.
       */
      compressor.reset();
    }
    return compressor;
  }
  return null;
}
 

@Test
public final void testInsertOverwriteWithCompression() throws Exception {
  String tableName = IdentifierUtil.normalizeIdentifier("testInsertOverwriteWithCompression");
  ResultSet res = executeFile("testInsertOverwriteWithCompression_ddl.sql");
  res.close();

  CatalogService catalog = testingCluster.getMaster().getCatalog();
  assertTrue(catalog.existsTable(getCurrentDatabase(), tableName));

  res = executeQuery();
  res.close();
  TableDesc desc = catalog.getTableDesc(getCurrentDatabase(), tableName);
  if (!testingCluster.isHiveCatalogStoreRunning()) {
    assertEquals(2, desc.getStats().getNumRows().intValue());
  }

  FileSystem fs = FileSystem.get(testingCluster.getConfiguration());
  assertTrue(fs.exists(new Path(desc.getUri())));
  CompressionCodecFactory factory = new CompressionCodecFactory(testingCluster.getConfiguration());

  for (FileStatus file : fs.listStatus(new Path(desc.getUri()))) {
    CompressionCodec codec = factory.getCodec(file.getPath());
    assertTrue(codec instanceof DeflateCodec);
  }
  executeString("DROP TABLE " + tableName + " PURGE");
}
 

@Override
public synchronized boolean isSupported() {
  if (!checked) {
    checked = true;
    String extClazz =
        (conf.get(CONF_LZO_CLASS) == null ? System
            .getProperty(CONF_LZO_CLASS) : null);
    String clazz = (extClazz != null) ? extClazz : defaultClazz;
    try {
      LOG.info("Trying to load Lzo codec class: " + clazz);
      codec =
          (CompressionCodec) ReflectionUtils.newInstance(Class
              .forName(clazz), conf);
    } catch (ClassNotFoundException e) {
      // that is okay
    }
  }
  return codec != null;
}
 

private static void writeTest(FileSystem fs, int count, int seed, Path file, 
                              CompressionType compressionType, CompressionCodec codec)
  throws IOException {
  fs.delete(file, true);
  LOG.info("creating " + count + " records with " + compressionType +
           " compression");
  SequenceFile.Writer writer = 
    SequenceFile.createWriter(fs, conf, file, 
                              RandomDatum.class, RandomDatum.class, compressionType, codec);
  RandomDatum.Generator generator = new RandomDatum.Generator(seed);
  for (int i = 0; i < count; i++) {
    generator.next();
    RandomDatum key = generator.getKey();
    RandomDatum value = generator.getValue();

    writer.append(key, value);
  }
  writer.close();
}
 

@Override
public void setStoreLocation(String location, Job job)
    throws IOException {
  job.setOutputKeyClass(keyClass);
  job.setOutputValueClass(valueClass);
  if (compressionType != null && compressionCodecClass != null) {
    Class<? extends CompressionCodec> codecClass =
        FileOutputFormat.getOutputCompressorClass(job,
            DefaultCodec.class);
    SequenceFileOutputFormat.
        setOutputCompressorClass(job, codecClass);
    SequenceFileOutputFormat.setOutputCompressionType(job,
        SequenceFile.CompressionType.valueOf(compressionType));
  }
  FileOutputFormat.setOutputPath(job, new Path(location));
}
 

/**
 * Clones the attributes (like compression of the input file and creates a 
 * corresponding Writer
 * @param inputFile the path of the input file whose attributes should be 
 * cloned
 * @param outputFile the path of the output file 
 * @param prog the Progressable to report status during the file write
 * @return Writer
 * @throws IOException
 */
public Writer cloneFileAttributes(Path inputFile, Path outputFile, 
                                  Progressable prog) 
throws IOException {
  FileSystem srcFileSys = inputFile.getFileSystem(conf);
  Reader reader = new Reader(srcFileSys, inputFile, 4096, conf, true);
  boolean compress = reader.isCompressed();
  boolean blockCompress = reader.isBlockCompressed();
  CompressionCodec codec = reader.getCompressionCodec();
  reader.close();

  Writer writer = createWriter(outputFile.getFileSystem(conf), conf, 
                               outputFile, keyClass, valClass, compress, 
                               blockCompress, codec, prog,
                               new Metadata());
  return writer;
}
 

public Writer(Configuration conf, FSDataOutputStream outputStream,
    Class keyClass, Class valueClass,
    CompressionCodec codec, TezCounter writesCounter, TezCounter serializedBytesCounter,
    boolean rle) throws IOException {
  this.rawOut = outputStream;
  this.writtenRecordsCounter = writesCounter;
  this.serializedUncompressedBytes = serializedBytesCounter;
  this.start = this.rawOut.getPos();
  this.rle = rle;

  setupOutputStream(codec);

  writeHeader(outputStream);

  if (keyClass != null) {
    this.closeSerializers = true;
    SerializationFactory serializationFactory =
      new SerializationFactory(conf);
    this.keySerializer = serializationFactory.getSerializer(keyClass);
    this.keySerializer.open(buffer);
    this.valueSerializer = serializationFactory.getSerializer(valueClass);
    this.valueSerializer.open(buffer);
  } else {
    this.closeSerializers = false;
  }
}
 

@Override
public boolean nextKeyValue() throws IOException, InterruptedException {
    if (currentPath>=split.getNumPaths()) {
        return false;
    }

    Path path = split.getPath(currentPath);
    currentPath++;

    CompressionCodecFactory factory = new CompressionCodecFactory(conf);
    CompressionCodec codec = factory.getCodec(path);
    key = path.toString();
    FSDataInputStream fileIn = fs.open(path);

    value = codec!=null?codec.createInputStream(fileIn):fileIn;
    return true;
}
 

@Override
public void open(String filePath, CompressionCodec codeC,
    CompressionType compType) throws IOException {
  super.open(filePath, codeC, compType);
  if(closed) {
    opened = true;
  }
}
 

/**
 * Test using the gzip codec for reading
 */
@Test(timeout=10000)
public void testGzip() throws IOException, InterruptedException {
  Configuration conf = new Configuration(defaultConf);
  CompressionCodec gzip = new GzipCodec();
  ReflectionUtils.setConf(gzip, conf);
  localFs.delete(workDir, true);
  writeFile(localFs, new Path(workDir, "part1.txt.gz"), gzip,
            "the quick\nbrown\nfox jumped\nover\n the lazy\n dog\n");
  writeFile(localFs, new Path(workDir, "part2.txt.gz"), gzip,
            "this is a test\nof gzip\n");
  Job job = Job.getInstance(conf);
  FileInputFormat.setInputPaths(job, workDir);
  CombineTextInputFormat format = new CombineTextInputFormat();
  List<InputSplit> splits = format.getSplits(job);
  assertEquals("compressed splits == 1", 1, splits.size());
  List<Text> results = readSplit(format, splits.get(0), job);
  assertEquals("splits[0] length", 8, results.size());

  final String[] firstList =
    {"the quick", "brown", "fox jumped", "over", " the lazy", " dog"};
  final String[] secondList = {"this is a test", "of gzip"};
  String first = results.get(0).toString();
  if (first.equals(firstList[0])) {
    testResults(results, firstList, secondList);
  } else if (first.equals(secondList[0])) {
    testResults(results, secondList, firstList);
  } else {
    fail("unexpected first token!");
  }
}
 

private void validateResults(File folder, List<String> expected, CompressionCodec codec) throws Exception {
	File[] buckets = folder.listFiles();
	assertNotNull(buckets);
	assertEquals(1, buckets.length);

	final File[] partFiles = buckets[0].listFiles();
	assertNotNull(partFiles);
	assertEquals(1, partFiles.length);

	for (File partFile : partFiles) {
		assertTrue(partFile.length() > 0);
		final List<String> fileContent = readFile(partFile, codec);
		assertEquals(expected, fileContent);
	}
}
 

public WARCWriter(TaskAttemptContext context) throws IOException {
    Configuration conf = context.getConfiguration();
    CompressionCodec codec = getCompressOutput(context) ? WARCFileWriter.getGzipCodec(conf)
            : null;
    Path workFile = getDefaultWorkFile(context, "");
    _writer = new WARCFileWriter(conf, codec, workFile);
}
 

public WarcFileRecordReader(Configuration conf, InputSplit split) throws IOException {
  if (split instanceof FileSplit) {
    this.filePathList=new Path[1];
    this.filePathList[0]=((FileSplit)split).getPath();
  } else if (split instanceof MultiFileSplit) {
    this.filePathList=((MultiFileSplit)split).getPaths();
  } else {
    throw new IOException("InputSplit is not a file split or a multi-file split - aborting");
  }

  // Use FileSystem.get to open Common Crawl URIs using the S3 protocol.
  URI uri = filePathList[0].toUri();
  this.fs = FileSystem.get(uri, conf);
  
  // get the total file sizes
  for (int i=0; i < filePathList.length; i++) {
    totalFileSize += fs.getFileStatus(filePathList[i]).getLen();
  }

  Class<? extends CompressionCodec> codecClass=null;

  try {
    codecClass=conf.getClassByName("org.apache.hadoop.io.compress.GzipCodec").asSubclass(CompressionCodec.class);
    compressionCodec=(CompressionCodec)ReflectionUtils.newInstance(codecClass, conf);
  } catch (ClassNotFoundException cnfEx) {
    compressionCodec=null;
    LOG.info("!!! ClassNotFoun Exception thrown setting Gzip codec");
  }

  openNextFile();
}
 

void testWithCodec(Class<? extends CompressionCodec> codecClass) throws Exception {
  CompressionCodec codec =
    codecClass == null ? null : ReflectionUtils.newInstance(codecClass, conf);
  testNormalWriteAndRead(1, 1024, 16, codec);
  testNormalWriteAndRead(10, 1024, 16, codec);
  testNormalWriteAndRead(1, 1024, 256, codec);
  testNormalWriteAndRead(10, 1024, 256, codec);
}
 

private static List<String> readLines(Path location, Configuration conf) throws Exception {
    FileSystem fileSystem = FileSystem.get(location.toUri(), conf);
    CompressionCodecFactory factory = new CompressionCodecFactory(conf);
    FileStatus[] items = fileSystem.listStatus(location);
    if (items == null)
        return new ArrayList<String>();
    List<String> results = new ArrayList<String>();
    for (FileStatus item : items) {

        // ignoring files like _SUCCESS
        if (item.getPath().getName().startsWith("_")) {
            continue;
        }

        CompressionCodec codec = factory.getCodec(item.getPath());
        InputStream stream = null;

        // check if we have a compression codec we need to use
        if (codec != null) {
            stream = codec.createInputStream(fileSystem.open(item.getPath()));
        } else {
            stream = fileSystem.open(item.getPath());
        }

        StringWriter writer = new StringWriter();
        IOUtils.copy(stream, writer, "UTF-8");
        String raw = writer.toString();
        for (String str : raw.split("\n")) {
            results.add(str);
        }
    }
    return results;
}