org.cloudgraph.hbase.mapreduce

Class GraphRecordReader

java.lang.Object

org.apache.hadoop.mapreduce.RecordReader<org.apache.hadoop.hbase.io.ImmutableBytesWritable,GraphWritable>

org.cloudgraph.hbase.mapreduce.GraphRecordReader

All Implemented Interfaces:

Closeable, AutoCloseable

public class GraphRecordReader
extends org.apache.hadoop.mapreduce.RecordReader<org.apache.hadoop.hbase.io.ImmutableBytesWritable,GraphWritable>

Iterates over HBase root table data for the current TableSplit, assembling data graphs based on the detailed selection criteria within a given query. Partially or fully assembled data graphs may be passed to a GraphRecordRecognizer and potentially screened from client GraphMapper extensions potentially illuminating business logic dedicated to identifying specific records.

Constructor Summary

Constructors

Constructor and Description
GraphRecordReader(org.apache.hadoop.conf.Configuration configuration)

Method Summary

Modifier and Type	Method and Description
void	close() Closes the split.
org.apache.hadoop.hbase.io.ImmutableBytesWritable	getCurrentKey() Returns the current key.
GraphWritable	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	setScan(org.apache.hadoop.hbase.client.Scan scan) Sets the scan defining the actual details like columns etc.
void	setTable(org.apache.hadoop.hbase.client.Table table) Sets the Table.

Methods inherited from class java.lang.Object

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

Constructor Detail

GraphRecordReader

public GraphRecordReader(org.apache.hadoop.conf.Configuration configuration)

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.

setTable

public void setTable(org.apache.hadoop.hbase.client.Table table)

Sets the Table.

Parameters:

table - The Table to scan.

setScan

public void setScan(org.apache.hadoop.hbase.client.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<org.apache.hadoop.hbase.io.ImmutableBytesWritable,GraphWritable>

See Also:

RecordReader.close()

getCurrentKey

public org.apache.hadoop.hbase.io.ImmutableBytesWritable getCurrentKey()
                                                                throws IOException,
                                                                       InterruptedException

Returns the current key.

Specified by:

getCurrentKey in class org.apache.hadoop.mapreduce.RecordReader<org.apache.hadoop.hbase.io.ImmutableBytesWritable,GraphWritable>

Returns:

The current key.

Throws:

IOException

InterruptedException - When the job is aborted.

See Also:

RecordReader.getCurrentKey()

getCurrentValue

public GraphWritable getCurrentValue()
                              throws IOException,
                                     InterruptedException

Returns the current value.

Specified by:

getCurrentValue in class org.apache.hadoop.mapreduce.RecordReader<org.apache.hadoop.hbase.io.ImmutableBytesWritable,GraphWritable>

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<org.apache.hadoop.hbase.io.ImmutableBytesWritable,GraphWritable>

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<org.apache.hadoop.hbase.io.ImmutableBytesWritable,GraphWritable>

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<org.apache.hadoop.hbase.io.ImmutableBytesWritable,GraphWritable>

Returns:

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

See Also:

RecordReader.getProgress()