org.apache.hadoop.mapred
Class SequenceFileRecordReader<K,V>

java.lang.Object
  org.apache.hadoop.mapred.SequenceFileRecordReader<K,V>

All Implemented Interfaces:

RecordReader<K,V>

public class SequenceFileRecordReader<K,V>
extends Object
implements RecordReader<K,V>

An RecordReader for SequenceFiles.

Field Summary

protected Configuration

conf

Constructor Summary

SequenceFileRecordReader(Configuration conf, FileSplit split)

Method Summary

void	close() Close this InputSplit to future operations.
K	createKey() Create an object of the appropriate type to be used as a key.
V	createValue() Create an object of the appropriate type to be used as a value.
protected void	getCurrentValue(V value)
Class	getKeyClass() The class of key that must be passed to next(Object, Object)..
long	getPos() Returns the current position in the input.
float	getProgress() Return the progress within the input split
Class	getValueClass() The class of value that must be passed to next(Object, Object)..
protected boolean	next(K key)
boolean	next(K key, V value) Reads the next key/value pair from the input for processing.
protected void	seek(long pos)

Methods inherited from class java.lang.Object

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

Field Detail

conf

protected Configuration conf

Constructor Detail

SequenceFileRecordReader

public SequenceFileRecordReader(Configuration conf,
                                FileSplit split)
                         throws IOException

Throws:

IOException

Method Detail

getKeyClass

public Class getKeyClass()

The class of key that must be passed to next(Object, Object)..

getValueClass

public Class getValueClass()

The class of value that must be passed to next(Object, Object)..

createKey

public K 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<K,V>

Returns:

a new key object.

createValue

public V createValue()

Description copied from interface: RecordReader

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

Specified by:

createValue in interface RecordReader<K,V>

Returns:

a new value object.

next

public boolean next(K key,
                    V value)
             throws IOException

Description copied from interface: RecordReader

Reads the next key/value pair from the input for processing.

Specified by:

next in interface RecordReader<K,V>

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

next

protected boolean next(K key)
                throws IOException

Throws:

IOException

getCurrentValue

protected void getCurrentValue(V value)
                        throws IOException

Throws:

IOException

getProgress

public float getProgress()
                  throws IOException

Return the progress within the input split

Specified by:

getProgress in interface RecordReader<K,V>

Returns:

0.0 to 1.0 of the input byte range

Throws:

IOException

getPos

public long getPos()
            throws IOException

Description copied from interface: RecordReader

Returns the current position in the input.

Specified by:

getPos in interface RecordReader<K,V>

Returns:

the current position in the input.

Throws:

IOException

seek

protected void seek(long pos)
             throws IOException

Throws:

IOException

close

public void close()
           throws IOException

Description copied from interface: RecordReader

Close this InputSplit to future operations.

Specified by:

close in interface RecordReader<K,V>

Throws:

IOException