org.apache.hadoop.mapreduce.lib.input

类 DelegatingRecordReader<K,V>

java.lang.Object

org.apache.hadoop.mapreduce.RecordReader<K,V>

org.apache.hadoop.mapreduce.lib.input.DelegatingRecordReader<K,V>

所有已实现的接口:

Closeable, AutoCloseable

@InterfaceAudience.Private
@InterfaceStability.Unstable
public class DelegatingRecordReader<K,V>
extends RecordReader<K,V>

This is a delegating RecordReader, which delegates the functionality to the underlying record reader in TaggedInputSplit

构造器概要

构造器

构造器和说明
DelegatingRecordReader(InputSplit split, TaskAttemptContext context) Constructs the DelegatingRecordReader.

方法概要

方法

限定符和类型	方法和说明
void	close() Close the record reader.
K	getCurrentKey() Get the current key
V	getCurrentValue() Get the current value.
float	getProgress() The current progress of the record reader through its data.
void	initialize(InputSplit split, TaskAttemptContext context) Called once at initialization.
boolean	nextKeyValue() Read the next key, value pair.

从类继承的方法 java.lang.Object

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

构造器详细资料

DelegatingRecordReader

public DelegatingRecordReader(InputSplit split,
                      TaskAttemptContext context)
                       throws IOException,
                              InterruptedException

Constructs the DelegatingRecordReader.

参数:

split - TaggegInputSplit object

context - TaskAttemptContext object

抛出:

IOException

InterruptedException

方法详细资料

close

public void close()
           throws IOException

从类复制的说明: RecordReader

Close the record reader.

指定者:

close 在接口中 Closeable

指定者:

close 在接口中 AutoCloseable

指定者:

close 在类中 RecordReader<K,V>

抛出:

IOException

getCurrentKey

public K getCurrentKey()
                throws IOException,
                       InterruptedException

从类复制的说明: RecordReader

Get the current key

指定者:

getCurrentKey 在类中 RecordReader<K,V>

返回:

the current key or null if there is no current key

抛出:

IOException

InterruptedException

getCurrentValue

public V getCurrentValue()
                  throws IOException,
                         InterruptedException

从类复制的说明: RecordReader

Get the current value.

指定者:

getCurrentValue 在类中 RecordReader<K,V>

返回:

the object that was read

抛出:

IOException

InterruptedException

getProgress

public float getProgress()
                  throws IOException,
                         InterruptedException

从类复制的说明: RecordReader

The current progress of the record reader through its data.

指定者:

getProgress 在类中 RecordReader<K,V>

返回:

a number between 0.0 and 1.0 that is the fraction of the data read

抛出:

IOException

InterruptedException

initialize

public void initialize(InputSplit split,
              TaskAttemptContext context)
                throws IOException,
                       InterruptedException

从类复制的说明: RecordReader

Called once at initialization.

指定者:

initialize 在类中 RecordReader<K,V>

参数:

split - the split that defines the range of records to read

context - the information about the task

抛出:

IOException

InterruptedException

nextKeyValue

public boolean nextKeyValue()
                     throws IOException,
                            InterruptedException

从类复制的说明: RecordReader

Read the next key, value pair.

指定者:

nextKeyValue 在类中 RecordReader<K,V>

返回:

true if a key/value pair was read

抛出:

IOException

InterruptedException