org.apache.hadoop.util
Class LineReader

java.lang.Object
  org.apache.hadoop.util.LineReader

Direct Known Subclasses:

LineRecordReader.LineReader

public class LineReader
extends Object

A class that provides a line reader from an input stream. Depending on the constructor used, lines will either be terminated by:

• one of the following: '\n' (LF) , '\r' (CR), or '\r\n' (CR+LF).
• or, a custom byte sequence delimiter

In both cases, EOF also terminates an otherwise unterminated line.

Constructor Summary

LineReader(InputStream in)
Create a line reader that reads from the given stream using the default buffer-size (64k).

LineReader(InputStream in, byte[] recordDelimiterBytes)
Create a line reader that reads from the given stream using the default buffer-size, and using a custom delimiter of array of bytes.

LineReader(InputStream in, Configuration conf)
Create a line reader that reads from the given stream using the io.file.buffer.size specified in the given Configuration.

LineReader(InputStream in, Configuration conf, byte[] recordDelimiterBytes)
Create a line reader that reads from the given stream using the io.file.buffer.size specified in the given Configuration, and using a custom delimiter of array of bytes.

LineReader(InputStream in, int bufferSize)
Create a line reader that reads from the given stream using the given buffer-size.

LineReader(InputStream in, int bufferSize, byte[] recordDelimiterBytes)
Create a line reader that reads from the given stream using the given buffer-size, and using a custom delimiter of array of bytes.

Method Summary

void	close() Close the underlying stream.
int	readLine(Text str) Read from the InputStream into the given Text.
int	readLine(Text str, int maxLineLength) Read from the InputStream into the given Text.
int	readLine(Text str, int maxLineLength, int maxBytesToConsume) Read one line from the InputStream into the given Text.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

LineReader

public LineReader(InputStream in)

Create a line reader that reads from the given stream using the default buffer-size (64k).

Parameters:

in - The input stream

Throws:

IOException

LineReader

public LineReader(InputStream in,
                  int bufferSize)

Create a line reader that reads from the given stream using the given buffer-size.

Parameters:

in - The input stream

bufferSize - Size of the read buffer

Throws:

IOException

LineReader

public LineReader(InputStream in,
                  Configuration conf)
           throws IOException

Create a line reader that reads from the given stream using the io.file.buffer.size specified in the given Configuration.

Parameters:

in - input stream

conf - configuration

Throws:

IOException

LineReader

public LineReader(InputStream in,
                  byte[] recordDelimiterBytes)

Create a line reader that reads from the given stream using the default buffer-size, and using a custom delimiter of array of bytes.

Parameters:

in - The input stream

recordDelimiterBytes - The delimiter

LineReader

public LineReader(InputStream in,
                  int bufferSize,
                  byte[] recordDelimiterBytes)

Create a line reader that reads from the given stream using the given buffer-size, and using a custom delimiter of array of bytes.

Parameters:

in - The input stream

bufferSize - Size of the read buffer

recordDelimiterBytes - The delimiter

Throws:

IOException

LineReader

public LineReader(InputStream in,
                  Configuration conf,
                  byte[] recordDelimiterBytes)
           throws IOException

Create a line reader that reads from the given stream using the io.file.buffer.size specified in the given Configuration, and using a custom delimiter of array of bytes.

Parameters:

in - input stream

conf - configuration

recordDelimiterBytes - The delimiter

Throws:

IOException

Method Detail

close

public void close()
           throws IOException

Close the underlying stream.

Throws:

IOException

readLine

public int readLine(Text str,
                    int maxLineLength,
                    int maxBytesToConsume)
             throws IOException

Read one line from the InputStream into the given Text.

Parameters:

str - the object to store the given line (without newline)

maxLineLength - the maximum number of bytes to store into str; the rest of the line is silently discarded.

maxBytesToConsume - the maximum number of bytes to consume in this call. This is only a hint, because if the line cross this threshold, we allow it to happen. It can overshoot potentially by as much as one buffer length.

Returns:

the number of bytes read including the (longest) newline found.

Throws:

IOException - if the underlying stream throws

readLine

public int readLine(Text str,
                    int maxLineLength)
             throws IOException

Read from the InputStream into the given Text.

Parameters:

str - the object to store the given line

maxLineLength - the maximum number of bytes to store into str.

Returns:

the number of bytes read including the newline

Throws:

IOException - if the underlying stream throws

readLine

public int readLine(Text str)
             throws IOException

Read from the InputStream into the given Text.

Parameters:

str - the object to store the given line

Returns:

the number of bytes read including the newline

Throws:

IOException - if the underlying stream throws