org.apache.hadoop.mapred
Class SequenceFileRecordReader

java.lang.Object
  org.apache.hadoop.mapred.SequenceFileRecordReader

All Implemented Interfaces:

RecordReader

Direct Known Subclasses:

SequenceFileAsTextRecordReader, StreamSequenceRecordReader

public class SequenceFileRecordReader
extends Object
implements RecordReader

An RecordReader for SequenceFiles.

Field Summary

protected Configuration

conf

Constructor Summary

SequenceFileRecordReader(Configuration conf, FileSplit split)

Method Summary

void	close() Close this to future operations.
WritableComparable	createKey() Create an object of the appropriate type to be used as a key.
Writable	createValue() Create an object of the appropriate type to be used as the value.
protected void	getCurrentValue(Writable value)
Class	getKeyClass() The class of key that must be passed to next(Writable,Writable)..
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(Writable,Writable)..
protected boolean	next(Writable key)
boolean	next(Writable key, Writable value) Reads the next key/value pair.
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(Writable,Writable)..

getValueClass

public Class getValueClass()

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

createKey

public WritableComparable 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

Returns:

a new key object

createValue

public Writable createValue()

Description copied from interface: RecordReader

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

Specified by:

createValue in interface RecordReader

Returns:

a new value object

next

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

Description copied from interface: RecordReader

Reads the next key/value pair.

Specified by:

next in interface RecordReader

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)

next

protected boolean next(Writable key)
                throws IOException

Throws:

IOException

getCurrentValue

protected void getCurrentValue(Writable value)
                        throws IOException

Throws:

IOException

getProgress

public float getProgress()
                  throws IOException

Return the progress within the input split

Specified by:

getProgress in interface RecordReader

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

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 to future operations.

Specified by:

close in interface RecordReader

Throws:

IOException