Package org.apache.hadoop.io.erasurecode.coder

Class XORErasureDecoder

java.lang.Object

org.apache.hadoop.conf.Configured

org.apache.hadoop.io.erasurecode.coder.ErasureDecoder

org.apache.hadoop.io.erasurecode.coder.XORErasureDecoder

All Implemented Interfaces:

Configurable, ErasureCoder

@Private
public class XORErasureDecoder
extends ErasureDecoder

Xor erasure decoder that decodes a block group. It implements ErasureCoder.

Constructor Summary

Constructors

Constructor	Description
XORErasureDecoder(ErasureCoderOptions options)

Method Summary

Modifier and Type	Method	Description
protected ECBlock[]	getOutputBlocks(ECBlockGroup blockGroup)	Which blocks were erased ?
protected ErasureCodingStep	prepareDecodingStep(ECBlockGroup blockGroup)	Perform decoding against a block blockGroup.

Methods inherited from class org.apache.hadoop.io.erasurecode.coder.ErasureDecoder

calculateCoding, getErasedIndexes, getInputBlocks, getNumDataUnits, getNumErasedBlocks, getNumErasedBlocks, getNumParityUnits, getOptions, preferDirectBuffer, release

Methods inherited from class org.apache.hadoop.conf.Configured

getConf, setConf

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.hadoop.conf.Configurable

getConf, setConf

Constructor Details

XORErasureDecoder

public XORErasureDecoder(ErasureCoderOptions options)

Method Details

prepareDecodingStep

protected ErasureCodingStep prepareDecodingStep(ECBlockGroup blockGroup)

Description copied from class: ErasureDecoder

Perform decoding against a block blockGroup.

Specified by:

prepareDecodingStep in class ErasureDecoder

Parameters:

blockGroup - blockGroup.

Returns:

decoding step for caller to do the real work

getOutputBlocks

protected ECBlock[] getOutputBlocks(ECBlockGroup blockGroup)

Which blocks were erased ? For XOR it's simple we only allow and return one erased block, either data or parity.

Overrides:

getOutputBlocks in class ErasureDecoder

Parameters:

blockGroup - blockGroup.

Returns:

output blocks to recover