org.apache.hadoop.mapreduce.lib.input

Class LineRecordReader

java.lang.Object

org.apache.hadoop.mapreduce.RecordReader<org.apache.hadoop.io.LongWritable,org.apache.hadoop.io.Text>

org.apache.hadoop.mapreduce.lib.input.LineRecordReader

All Implemented Interfaces:

Closeable, AutoCloseable

@InterfaceAudience.LimitedPrivate(value={"MapReduce","Pig"})
@InterfaceStability.Evolving
public class LineRecordReader
extends RecordReader<org.apache.hadoop.io.LongWritable,org.apache.hadoop.io.Text>

Treats keys as offset in file and value as line.

Field Summary

Fields

Modifier and Type	Field and Description
static String	MAX_LINE_LENGTH

Constructor Summary

Constructors

Constructor and Description
LineRecordReader()
LineRecordReader(byte[] recordDelimiter)

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Close the record reader.
org.apache.hadoop.io.LongWritable	getCurrentKey() Get the current key
org.apache.hadoop.io.Text	getCurrentValue() Get the current value.
float	getProgress() Get the progress within the split
void	initialize(InputSplit genericSplit, TaskAttemptContext context) Called once at initialization.
boolean	nextKeyValue() Read the next key, value pair.

Methods inherited from class java.lang.Object

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

Field Detail

MAX_LINE_LENGTH

public static final String MAX_LINE_LENGTH

See Also:

Constant Field Values

Constructor Detail

LineRecordReader

public LineRecordReader()

LineRecordReader

public LineRecordReader(byte[] recordDelimiter)

Method Detail

initialize

public void initialize(InputSplit genericSplit,
              TaskAttemptContext context)
                throws IOException

Description copied from class: RecordReader

Called once at initialization.

Specified by:

initialize in class RecordReader<org.apache.hadoop.io.LongWritable,org.apache.hadoop.io.Text>

Parameters:

genericSplit - the split that defines the range of records to read

context - the information about the task

Throws:

IOException

nextKeyValue

public boolean nextKeyValue()
                     throws IOException

Description copied from class: RecordReader

Read the next key, value pair.

Specified by:

nextKeyValue in class RecordReader<org.apache.hadoop.io.LongWritable,org.apache.hadoop.io.Text>

Returns:

true if a key/value pair was read

Throws:

IOException

getCurrentKey

public org.apache.hadoop.io.LongWritable getCurrentKey()

Description copied from class: RecordReader

Get the current key

Specified by:

getCurrentKey in class RecordReader<org.apache.hadoop.io.LongWritable,org.apache.hadoop.io.Text>

Returns:

the current key or null if there is no current key

getCurrentValue

public org.apache.hadoop.io.Text getCurrentValue()

Description copied from class: RecordReader

Get the current value.

Specified by:

getCurrentValue in class RecordReader<org.apache.hadoop.io.LongWritable,org.apache.hadoop.io.Text>

Returns:

the object that was read

getProgress

public float getProgress()
                  throws IOException

Get the progress within the split

Specified by:

getProgress in class RecordReader<org.apache.hadoop.io.LongWritable,org.apache.hadoop.io.Text>

Returns:

a number between 0.0 and 1.0 that is the fraction of the data read

Throws:

IOException

close

public void close()
           throws IOException

Description copied from class: RecordReader

Close the record reader.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in class RecordReader<org.apache.hadoop.io.LongWritable,org.apache.hadoop.io.Text>

Throws:

IOException