/// <exception cref="System.IO.IOException"/>
public override void Initialize(InputSplit genericSplit, TaskAttemptContext context
)
{
FileSplit split = (FileSplit)genericSplit;
Configuration job = context.GetConfiguration();
this.maxLineLength = job.GetInt(MaxLineLength, int.MaxValue);
start = split.GetStart();
end = start + split.GetLength();
Path file = split.GetPath();
// open the file and seek to the start of the split
FileSystem fs = file.GetFileSystem(job);
fileIn = fs.Open(file);
CompressionCodec codec = new CompressionCodecFactory(job).GetCodec(file);
if (null != codec)
{
isCompressedInput = true;
decompressor = CodecPool.GetDecompressor(codec);
if (codec is SplittableCompressionCodec)
{
SplitCompressionInputStream cIn = ((SplittableCompressionCodec)codec).CreateInputStream
(fileIn, decompressor, start, end, SplittableCompressionCodec.READ_MODE.Byblock);
@in = new CompressedSplitLineReader(cIn, job, this.recordDelimiterBytes);
start = cIn.GetAdjustedStart();
end = cIn.GetAdjustedEnd();
filePosition = cIn;
}
else
{
@in = new SplitLineReader(codec.CreateInputStream(fileIn, decompressor), job, this
.recordDelimiterBytes);
filePosition = fileIn;
}
}
else
{
fileIn.Seek(start);
@in = new UncompressedSplitLineReader(fileIn, job, this.recordDelimiterBytes, split
.GetLength());
filePosition = fileIn;
}
// If this is not the first split, we always throw away first record
// because we always (except the last split) read one extra line in
// next() method.
if (start != 0)
{
start += @in.ReadLine(new Text(), 0, MaxBytesToConsume(start));
}
this.pos = start;
}
// This is also called from the old FixedLengthRecordReader API implementation
/// <exception cref="System.IO.IOException"/>
public virtual void Initialize(Configuration job, long splitStart, long splitLength
, Path file)
{
start = splitStart;
end = start + splitLength;
long partialRecordLength = start % recordLength;
long numBytesToSkip = 0;
if (partialRecordLength != 0)
{
numBytesToSkip = recordLength - partialRecordLength;
}
// open the file and seek to the start of the split
FileSystem fs = file.GetFileSystem(job);
fileIn = fs.Open(file);
CompressionCodec codec = new CompressionCodecFactory(job).GetCodec(file);
if (null != codec)
{
isCompressedInput = true;
decompressor = CodecPool.GetDecompressor(codec);
CompressionInputStream cIn = codec.CreateInputStream(fileIn, decompressor);
filePosition = cIn;
inputStream = cIn;
numRecordsRemainingInSplit = long.MaxValue;
Log.Info("Compressed input; cannot compute number of records in the split");
}
else
{
fileIn.Seek(start);
filePosition = fileIn;
inputStream = fileIn;
long splitSize = end - start - numBytesToSkip;
numRecordsRemainingInSplit = (splitSize + recordLength - 1) / recordLength;
if (numRecordsRemainingInSplit < 0)
{
numRecordsRemainingInSplit = 0;
}
Log.Info("Expecting " + numRecordsRemainingInSplit + " records each with a length of "
+ recordLength + " bytes in the split with an effective size of " + splitSize +
" bytes");
}
if (numBytesToSkip != 0)
{
start += inputStream.Skip(numBytesToSkip);
}
this.pos = start;
}