org.apache.hadoop.mapreduce.lib.input

类 LineRecordReader

java.lang.Object

org.apache.hadoop.mapreduce.RecordReader<LongWritable,Text>

org.apache.hadoop.mapreduce.lib.input.LineRecordReader

所有已实现的接口:

Closeable, AutoCloseable

public class LineRecordReader
extends RecordReader<LongWritable,Text>

Treats keys as offset in file and value as line.

构造器概要

构造器

构造器和说明
LineRecordReader()

方法概要

方法

限定符和类型	方法和说明
void	close() Close the record reader.
LongWritable	getCurrentKey() Get the current key
Text	getCurrentValue() Get the current value.
float	getProgress() Get the progress within the split
void	initialize(InputSplit genericSplit, 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

LineRecordReader

public LineRecordReader()

方法详细资料

initialize

public void initialize(InputSplit genericSplit,
              TaskAttemptContext context)
                throws IOException

从类复制的说明: RecordReader

Called once at initialization.

指定者:

initialize 在类中 RecordReader<LongWritable,Text>

参数:

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

context - the information about the task

抛出:

IOException

nextKeyValue

public boolean nextKeyValue()
                     throws IOException

从类复制的说明: RecordReader

Read the next key, value pair.

指定者:

nextKeyValue 在类中 RecordReader<LongWritable,Text>

返回:

true if a key/value pair was read

抛出:

IOException

getCurrentKey

public LongWritable getCurrentKey()

从类复制的说明: RecordReader

Get the current key

指定者:

getCurrentKey 在类中 RecordReader<LongWritable,Text>

返回:

the current key or null if there is no current key

getCurrentValue

public Text getCurrentValue()

从类复制的说明: RecordReader

Get the current value.

指定者:

getCurrentValue 在类中 RecordReader<LongWritable,Text>

返回:

the object that was read

getProgress

public float getProgress()
                  throws IOException

Get the progress within the split

指定者:

getProgress 在类中 RecordReader<LongWritable,Text>

返回:

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

抛出:

IOException

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<LongWritable,Text>

抛出:

IOException