org.apache.hadoop.mapred.lib

类 CombineFileRecordReader<K,V>

java.lang.Object

org.apache.hadoop.mapred.lib.CombineFileRecordReader<K,V>

所有已实现的接口:

RecordReader<K,V>

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

A generic RecordReader that can hand out different recordReaders for each chunk in a CombineFileSplit. A CombineFileSplit can combine data chunks from multiple files. This class allows using different RecordReaders for processing these data chunks from different files.

另请参阅:

CombineFileSplit

字段概要

字段

限定符和类型	字段和说明
protected RecordReader<K,V>	curReader
protected FileSystem	fs
protected int	idx
protected JobConf	jc
protected long	progress
protected Reporter	reporter
protected Class<RecordReader<K,V>>	rrClass
protected Constructor<RecordReader<K,V>>	rrConstructor
protected CombineFileSplit	split

构造器概要

构造器

构造器和说明
CombineFileRecordReader(JobConf job, CombineFileSplit split, Reporter reporter, Class<RecordReader<K,V>> rrClass) A generic RecordReader that can hand out different recordReaders for each chunk in the CombineFileSplit.

方法概要

方法

限定符和类型	方法和说明
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.
long	getPos() return the amount of data processed
float	getProgress() return progress based on the amount of data processed so far.
protected boolean	initNextRecordReader() Get the record reader for the next chunk in this CombineFileSplit.
boolean	next(K key, V value) Reads the next key/value pair from the input for processing.

从类继承的方法 java.lang.Object

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

字段详细资料

split

protected CombineFileSplit split

jc

protected JobConf jc

reporter

protected Reporter reporter

rrClass

protected Class<RecordReader<K,V>> rrClass

rrConstructor

protected Constructor<RecordReader<K,V>> rrConstructor

fs

protected FileSystem fs

idx

protected int idx

progress

protected long progress

curReader

protected RecordReader<K,V> curReader

构造器详细资料

CombineFileRecordReader

public CombineFileRecordReader(JobConf job,
                       CombineFileSplit split,
                       Reporter reporter,
                       Class<RecordReader<K,V>> rrClass)
                        throws IOException

A generic RecordReader that can hand out different recordReaders for each chunk in the CombineFileSplit.

抛出:

IOException

方法详细资料

next

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

从接口复制的说明: RecordReader

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

指定者:

next 在接口中 RecordReader<K,V>

参数:

key - the key to read data into

value - the value to read data into

返回:

true iff a key/value was read, false if at EOF

抛出:

IOException

createKey

public K createKey()

从接口复制的说明: RecordReader

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

指定者:

createKey 在接口中 RecordReader<K,V>

返回:

a new key object.

createValue

public V createValue()

从接口复制的说明: RecordReader

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

指定者:

createValue 在接口中 RecordReader<K,V>

返回:

a new value object.

getPos

public long getPos()
            throws IOException

return the amount of data processed

指定者:

getPos 在接口中 RecordReader<K,V>

返回:

the current position in the input.

抛出:

IOException

close

public void close()
           throws IOException

从接口复制的说明: RecordReader

Close this InputSplit to future operations.

指定者:

close 在接口中 RecordReader<K,V>

抛出:

IOException

getProgress

public float getProgress()
                  throws IOException

return progress based on the amount of data processed so far.

指定者:

getProgress 在接口中 RecordReader<K,V>

返回:

progress from 0.0 to 1.0.

抛出:

IOException

initNextRecordReader

protected boolean initNextRecordReader()
                                throws IOException

Get the record reader for the next chunk in this CombineFileSplit.

抛出:

IOException