org.apache.hadoop.mapred

类 SequenceFileRecordReader<K,V>

java.lang.Object

org.apache.hadoop.mapred.SequenceFileRecordReader<K,V>

所有已实现的接口:

RecordReader<K,V>

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

An RecordReader for SequenceFiles.

字段概要

字段

限定符和类型	字段和说明
protected Configuration	conf

构造器概要

构造器

构造器和说明
SequenceFileRecordReader(Configuration conf, FileSplit split)

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.
protected void	getCurrentValue(V value)
Class	getKeyClass() The class of key that must be passed to next(Object, Object)..
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(Object, Object)..
protected boolean	next(K key)
boolean	next(K key, V value) Reads the next key/value pair from the input for processing.
protected void	seek(long pos)

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

conf

protected Configuration conf

构造器详细资料

SequenceFileRecordReader

public SequenceFileRecordReader(Configuration conf,
                        FileSplit split)
                         throws IOException

抛出:

IOException

方法详细资料

getKeyClass

public Class getKeyClass()

The class of key that must be passed to next(Object, Object)..

getValueClass

public Class getValueClass()

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

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.

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

next

protected boolean next(K key)
                throws IOException

抛出:

IOException

getCurrentValue

protected void getCurrentValue(V value)
                        throws IOException

抛出:

IOException

getProgress

public float getProgress()
                  throws IOException

Return the progress within the input split

指定者:

getProgress 在接口中 RecordReader<K,V>

返回:

0.0 to 1.0 of the input byte range

抛出:

IOException

getPos

public long getPos()
            throws IOException

从接口复制的说明: RecordReader

Returns the current position in the input.

指定者:

getPos 在接口中 RecordReader<K,V>

返回:

the current position in the input.

抛出:

IOException

seek

protected void seek(long pos)
             throws IOException

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