org.apache.hadoop.mapred
Class KeyValueLineRecordReader

java.lang.Object
  org.apache.hadoop.mapred.LineRecordReader
      org.apache.hadoop.mapred.KeyValueLineRecordReader

All Implemented Interfaces:

RecordReader

Direct Known Subclasses:

StreamLineRecordReader

public class KeyValueLineRecordReader
extends LineRecordReader

This class treats a line in the input as a key/value pair separated by a separator character. The separator can be specified in config file under the attribute name key.value.separator.in.input.line. The default separator is the tab character ('\t').

Constructor Summary

KeyValueLineRecordReader(Configuration job, FileSplit split)

Method Summary

Text	createKey() Create an object of the appropriate type to be used as a key.
static int	findSeparator(byte[] utf, int start, int length, byte sep)
Class	getKeyClass()
boolean	next(Writable key, Writable value) Read key/value pair in a line.

Methods inherited from class org.apache.hadoop.mapred.LineRecordReader

close, createValue, getPos, getProgress, readLine, readLine

Methods inherited from class java.lang.Object

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

Constructor Detail

KeyValueLineRecordReader

public KeyValueLineRecordReader(Configuration job,
                                FileSplit split)
                         throws IOException

Throws:

IOException

Method Detail

getKeyClass

public Class getKeyClass()

createKey

public Text createKey()

Description copied from interface: RecordReader

Create an object of the appropriate type to be used as a key.

Specified by:

createKey in interface RecordReader

Overrides:

createKey in class LineRecordReader

Returns:

a new key object

findSeparator

public static int findSeparator(byte[] utf,
                                int start,
                                int length,
                                byte sep)

next

public boolean next(Writable key,
                    Writable value)
             throws IOException

Read key/value pair in a line.

Specified by:

next in interface RecordReader

Overrides:

next in class LineRecordReader

Parameters:

key - the key to read data into

value - the value to read data into

Returns:

true iff a key/value was read, false if at EOF

Throws:

IOException

See Also:

Writable.readFields(DataInput)