org.apache.hadoop.hbase.mapreduce

Class TableRecordReader

java.lang.Object

org.apache.hadoop.mapreduce.RecordReader<ImmutableBytesWritable,Result>

org.apache.hadoop.hbase.mapreduce.TableRecordReader

All Implemented Interfaces:

Closeable, AutoCloseable

@InterfaceAudience.Public
@InterfaceStability.Stable
public class TableRecordReader
extends org.apache.hadoop.mapreduce.RecordReader<ImmutableBytesWritable,Result>

Iterate over an HBase table data, return (ImmutableBytesWritable, Result) pairs.

Constructor Summary

Constructors

Constructor and Description
TableRecordReader()

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Closes the split.
ImmutableBytesWritable	getCurrentKey() Returns the current key.
Result	getCurrentValue() Returns the current value.
float	getProgress() The current progress of the record reader through its data.
void	initialize(org.apache.hadoop.mapreduce.InputSplit inputsplit, org.apache.hadoop.mapreduce.TaskAttemptContext context) Initializes the reader.
boolean	nextKeyValue() Positions the record reader to the next record.
void	restart(byte[] firstRow) Restart from survivable exceptions by creating a new scanner.
void	setHTable(HTable htable) Sets the HBase table.
void	setScan(Scan scan) Sets the scan defining the actual details like columns etc.

Methods inherited from class java.lang.Object

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

Constructor Detail

TableRecordReader

public TableRecordReader()

Method Detail

restart

public void restart(byte[] firstRow)
             throws IOException

Restart from survivable exceptions by creating a new scanner.

Parameters:

firstRow - The first row to start at.

Throws:

IOException - When restarting fails.

setHTable

public void setHTable(HTable htable)

Sets the HBase table.

Parameters:

htable - The HTable to scan.

setScan

public void setScan(Scan scan)

Sets the scan defining the actual details like columns etc.

Parameters:

scan - The scan to set.

close

public void close()

Closes the split.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in class org.apache.hadoop.mapreduce.RecordReader<ImmutableBytesWritable,Result>

See Also:

RecordReader.close()

getCurrentKey

public ImmutableBytesWritable getCurrentKey()
                                     throws IOException,
                                            InterruptedException

Returns the current key.

Specified by:

getCurrentKey in class org.apache.hadoop.mapreduce.RecordReader<ImmutableBytesWritable,Result>

Returns:

The current key.

Throws:

IOException

InterruptedException - When the job is aborted.

See Also:

RecordReader.getCurrentKey()

getCurrentValue

public Result getCurrentValue()
                       throws IOException,
                              InterruptedException

Returns the current value.

Specified by:

getCurrentValue in class org.apache.hadoop.mapreduce.RecordReader<ImmutableBytesWritable,Result>

Returns:

The current value.

Throws:

IOException - When the value is faulty.

InterruptedException - When the job is aborted.

See Also:

RecordReader.getCurrentValue()

initialize

public void initialize(org.apache.hadoop.mapreduce.InputSplit inputsplit,
              org.apache.hadoop.mapreduce.TaskAttemptContext context)
                throws IOException,
                       InterruptedException

Initializes the reader.

Specified by:

initialize in class org.apache.hadoop.mapreduce.RecordReader<ImmutableBytesWritable,Result>

Parameters:

inputsplit - The split to work with.

context - The current task context.

Throws:

IOException - When setting up the reader fails.

InterruptedException - When the job is aborted.

See Also:

RecordReader.initialize( org.apache.hadoop.mapreduce.InputSplit, org.apache.hadoop.mapreduce.TaskAttemptContext)

nextKeyValue

public boolean nextKeyValue()
                     throws IOException,
                            InterruptedException

Positions the record reader to the next record.

Specified by:

nextKeyValue in class org.apache.hadoop.mapreduce.RecordReader<ImmutableBytesWritable,Result>

Returns:

true if there was another record.

Throws:

IOException - When reading the record failed.

InterruptedException - When the job was aborted.

See Also:

RecordReader.nextKeyValue()

getProgress

public float getProgress()

The current progress of the record reader through its data.

Specified by:

getProgress in class org.apache.hadoop.mapreduce.RecordReader<ImmutableBytesWritable,Result>

Returns:

A number between 0.0 and 1.0, the fraction of the data read.

See Also:

RecordReader.getProgress()