com.google.appengine.tools.mapreduce.outputs

Class ForwardingOutputWriter<O>

java.lang.Object

com.google.appengine.tools.mapreduce.OutputWriter<O>

com.google.appengine.tools.mapreduce.outputs.ForwardingOutputWriter<O>

Type Parameters:

O - type of values accepted by this output

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

ItemSegmentingOutputWriter, LevelDbOutputWriter, MarshallingOutputWriter

public abstract class ForwardingOutputWriter<O>
extends OutputWriter<O>

Author:

ohler@google.com (Christian Ohler)

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
ForwardingOutputWriter()

Method Summary

Methods

Modifier and Type	Method and Description
boolean	allowSliceRetry()
void	beginShard() Will be called once before any calls to write.
void	beginSlice() Prepares the writer for writing after possibly having gone through serialization or deserialization.
void	endShard() Called when no more output will be written to this writer.
void	endSlice() Prepares the writer for possible serialization.
long	estimateMemoryRequirement() Returns the estimated memory that will be used by this writer in bytes.
ShardContext	getContext() Returns the current context, or null if none.
protected abstract OutputWriter<?>	getDelegate()
void	setContext(ShardContext context) Used internally to sets the context to be used for the processing that follows.

Methods inherited from class com.google.appengine.tools.mapreduce.OutputWriter

cleanup, close, open, write

Methods inherited from class java.lang.Object

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

Constructor Detail

ForwardingOutputWriter

public ForwardingOutputWriter()

Method Detail

getDelegate

protected abstract OutputWriter<?> getDelegate()

beginShard

public void beginShard()
                throws IOException

Description copied from class: OutputWriter

Will be called once before any calls to write. Prepares the writer for processing, after possibly having gone through serialization and deserialization.

Overrides:

beginShard in class OutputWriter<O>

Throws:

IOException - in the event of failure

beginSlice

public void beginSlice()
                throws IOException

Description copied from class: OutputWriter

Prepares the writer for writing after possibly having gone through serialization or deserialization.

Overrides:

beginSlice in class OutputWriter<O>

Throws:

IOException - in the event of failure

endSlice

public void endSlice()
              throws IOException

Description copied from class: OutputWriter

Prepares the writer for possible serialization.

Overrides:

endSlice in class OutputWriter<O>

Throws:

IOException - in the event of failure

endShard

public void endShard()
              throws IOException

Description copied from class: OutputWriter

Called when no more output will be written to this writer.

Overrides:

endShard in class OutputWriter<O>

Throws:

IOException

estimateMemoryRequirement

public long estimateMemoryRequirement()

Description copied from class: OutputWriter

Returns the estimated memory that will be used by this writer in bytes. (This is normally just set to the size of the buffers used by the implementation)

Overrides:

estimateMemoryRequirement in class OutputWriter<O>

setContext

public void setContext(ShardContext context)

Description copied from class: OutputWriter

Used internally to sets the context to be used for the processing that follows.

Overrides:

setContext in class OutputWriter<O>

getContext

public ShardContext getContext()

Description copied from class: OutputWriter

Returns the current context, or null if none.

Overrides:

getContext in class OutputWriter<O>

allowSliceRetry

public boolean allowSliceRetry()

Overrides:

allowSliceRetry in class OutputWriter<O>