org.apache.hadoop.streaming

类 StreamBaseRecordReader

java.lang.Object

org.apache.hadoop.streaming.StreamBaseRecordReader

所有已实现的接口:

RecordReader<Text,Text>

直接已知子类:

StreamXmlRecordReader

public abstract class StreamBaseRecordReader
extends Object
implements RecordReader<Text,Text>

Shared functionality for hadoopStreaming formats. A custom reader can be defined to be a RecordReader with the constructor below and is selected with the option bin/hadoopStreaming -inputreader ...

另请参阅:

StreamXmlRecordReader

字段概要

字段

限定符和类型	字段和说明
protected static org.apache.commons.logging.Log	LOG

构造器概要

构造器

构造器和说明
StreamBaseRecordReader(FSDataInputStream in, FileSplit split, Reporter reporter, JobConf job, FileSystem fs)

方法概要

方法

限定符和类型	方法和说明
void	close() Close this to future operations.
Text	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() How much of the input has the RecordReader consumed i.e.
abstract boolean	next(Text key, Text value) Read a record.
abstract void	seekNextRecordBoundary() Implementation should seek forward in_ to the first byte of the next record.

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

LOG

protected static final org.apache.commons.logging.Log LOG

构造器详细资料

StreamBaseRecordReader

public StreamBaseRecordReader(FSDataInputStream in,
                      FileSplit split,
                      Reporter reporter,
                      JobConf job,
                      FileSystem fs)
                       throws IOException

抛出:

IOException

方法详细资料

next

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

Read a record. Implementation should call numRecStats at the end

指定者:

next 在接口中 RecordReader<Text,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

getPos

public long getPos()
            throws IOException

Returns the current position in the input.

指定者:

getPos 在接口中 RecordReader<Text,Text>

返回:

the current position in the input.

抛出:

IOException

close

public void close()
           throws IOException

Close this to future operations.

指定者:

close 在接口中 RecordReader<Text,Text>

抛出:

IOException

getProgress

public float getProgress()
                  throws IOException

从接口复制的说明: RecordReader

How much of the input has the RecordReader consumed i.e. has been processed by?

指定者:

getProgress 在接口中 RecordReader<Text,Text>

返回:

progress from 0.0 to 1.0.

抛出:

IOException

createKey

public Text 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<Text,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<Text,Text>

返回:

a new value object.

seekNextRecordBoundary

public abstract void seekNextRecordBoundary()
                                     throws IOException

Implementation should seek forward in_ to the first byte of the next record. The initial byte offset in the stream is arbitrary.

抛出:

IOException