org.springframework.yarn.batch.item

Class DataStoreItemReader<T>

java.lang.Object

org.springframework.yarn.batch.item.DataStoreItemReader<T>

Type Parameters:

T - the type of object returned as item read

All Implemented Interfaces:

org.springframework.batch.item.ItemReader<T>, org.springframework.batch.item.ItemStream, org.springframework.batch.item.ItemStreamReader<T>

public class DataStoreItemReader<T>
extends java.lang.Object
implements org.springframework.batch.item.ItemStreamReader<T>

Implementation of ItemReader able to read items from HDFS file splits.

Author:

Janne Valkealahti

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	READ_POSITION

Constructor Summary

Constructors

Constructor and Description
DataStoreItemReader() Instantiates a new data store item reader.
DataStoreItemReader(DataStoreReader<T> dataStoreReader) Instantiates a new data store item reader.

Method Summary

Methods

Modifier and Type	Method and Description
void	close()
boolean	isSaveState() The flag that determines whether to save internal state for restarts.
void	open(org.springframework.batch.item.ExecutionContext executionContext)
T	read()
void	setDataStoreReader(DataStoreReader<T> dataStoreReader) Sets the data store reader.
void	setLineDataMapper(LineDataMapper<T> lineDataMapper) Sets the line data mapper.
void	setSaveState(boolean saveState) Set the flag that determines whether to save internal data for ExecutionContext.
void	update(org.springframework.batch.item.ExecutionContext executionContext)

Methods inherited from class java.lang.Object

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

Field Detail

READ_POSITION

public static final java.lang.String READ_POSITION

See Also:

Constant Field Values

Constructor Detail

DataStoreItemReader

public DataStoreItemReader()

Instantiates a new data store item reader.

DataStoreItemReader

public DataStoreItemReader(DataStoreReader<T> dataStoreReader)

Instantiates a new data store item reader.

Parameters:

dataStoreReader - the data store reader

Method Detail

open

public void open(org.springframework.batch.item.ExecutionContext executionContext)
          throws org.springframework.batch.item.ItemStreamException

Specified by:

open in interface org.springframework.batch.item.ItemStream

Throws:

org.springframework.batch.item.ItemStreamException

update

public void update(org.springframework.batch.item.ExecutionContext executionContext)
            throws org.springframework.batch.item.ItemStreamException

Specified by:

update in interface org.springframework.batch.item.ItemStream

Throws:

org.springframework.batch.item.ItemStreamException

close

public void close()
           throws org.springframework.batch.item.ItemStreamException

Specified by:

close in interface org.springframework.batch.item.ItemStream

Throws:

org.springframework.batch.item.ItemStreamException

read

public T read()
       throws java.lang.Exception,
              org.springframework.batch.item.UnexpectedInputException,
              org.springframework.batch.item.ParseException,
              org.springframework.batch.item.NonTransientResourceException

Specified by:

read in interface org.springframework.batch.item.ItemReader<T>

Throws:

java.lang.Exception

org.springframework.batch.item.UnexpectedInputException

org.springframework.batch.item.ParseException

org.springframework.batch.item.NonTransientResourceException

setLineDataMapper

public void setLineDataMapper(LineDataMapper<T> lineDataMapper)

Sets the line data mapper.

Parameters:

lineDataMapper - the new line data mapper

setDataStoreReader

public void setDataStoreReader(DataStoreReader<T> dataStoreReader)

Sets the data store reader.

Parameters:

dataStoreReader - the new data store reader

setSaveState

public void setSaveState(boolean saveState)

Set the flag that determines whether to save internal data for ExecutionContext. Only switch this to false if you don't want to save any state from this stream, and you don't need it to be restartable. Always set it to false if the reader is being used in a concurrent environment.

Parameters:

saveState - flag value (default true).

isSaveState

public boolean isSaveState()

The flag that determines whether to save internal state for restarts.

Returns:

true if the flag was set