org.apache.hadoop.mapred

类 LineRecordReader

java.lang.Object

org.apache.hadoop.mapred.LineRecordReader

所有已实现的接口:

RecordReader<LongWritable,Text>

public class LineRecordReader
extends Object
implements RecordReader<LongWritable,Text>

Treats keys as offset in file and value as line.

嵌套类概要

嵌套类

限定符和类型	类和说明
static class	LineRecordReader.LineReader 已过时。 Use LineReader instead.

构造器概要

构造器

构造器和说明
LineRecordReader(Configuration job, FileSplit split)
LineRecordReader(InputStream in, long offset, long endOffset, Configuration job)
LineRecordReader(InputStream in, long offset, long endOffset, int maxLineLength)

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.
LongWritable	createKey() Create an object of the appropriate type to be used as a key.
Text	createValue() Create an object of the appropriate type to be used as a value.
long	getPos() Returns the current position in the input.
float	getProgress() Get the progress within the split
boolean	next(LongWritable key, Text value) Read a line.

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(Configuration job,
                FileSplit split)
                 throws IOException

抛出:

IOException

LineRecordReader

public LineRecordReader(InputStream in,
                long offset,
                long endOffset,
                int maxLineLength)

LineRecordReader

public LineRecordReader(InputStream in,
                long offset,
                long endOffset,
                Configuration job)
                 throws IOException

抛出:

IOException

方法详细资料

createKey

public LongWritable 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<LongWritable,Text>

返回:

a new key object.

createValue

public Text 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<LongWritable,Text>

返回:

a new value object.

next

public boolean next(LongWritable key,
           Text value)
             throws IOException

Read a line.

指定者:

next 在接口中 RecordReader<LongWritable,Text>

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

getProgress

public float getProgress()
                  throws IOException

Get the progress within the split

指定者:

getProgress 在接口中 RecordReader<LongWritable,Text>

返回:

progress from 0.0 to 1.0.

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<LongWritable,Text>

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<LongWritable,Text>

抛出:

IOException