com.google.appengine.tools.mapreduce.outputs

Class LevelDbOutputWriter

java.lang.Object

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

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

com.google.appengine.tools.mapreduce.outputs.LevelDbOutputWriter

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

GoogleCloudStorageLevelDbOutputWriter

public class LevelDbOutputWriter
extends ForwardingOutputWriter<ByteBuffer>

An implementation of a LevelDb format writer. Output of this class can be read by LevelDbInputReader. If you want to read about the format spec it is here: "https://github.com/google/leveldb/" This implementation deviates from the specification above, in that it allows blocks to be zero padded regardless of how much data is in the block, rather than only if the block is within 6 bytes of full.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
LevelDbOutputWriter(OutputWriter<ByteBuffer> delegate)

Method Summary

Methods

Modifier and Type	Method and Description
void	beginSlice() Prepares the writer for writing after possibly having gone through serialization or deserialization.
void	endShard() Closes the OutputChannel.
void	endSlice() Prepares the writer for possible serialization.
protected OutputWriter<ByteBuffer>	getDelegate()
protected int	getNumBlocksWritten()
void	write(ByteBuffer data) Writes a value to the output.

Methods inherited from class com.google.appengine.tools.mapreduce.outputs.ForwardingOutputWriter

allowSliceRetry, beginShard, estimateMemoryRequirement, getContext, setContext

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

cleanup, close, open

Methods inherited from class java.lang.Object

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

Constructor Detail

LevelDbOutputWriter

public LevelDbOutputWriter(OutputWriter<ByteBuffer> delegate)

Method Detail

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 ForwardingOutputWriter<ByteBuffer>

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 ForwardingOutputWriter<ByteBuffer>

Throws:

IOException - in the event of failure

write

public void write(ByteBuffer data)
           throws IOException

Description copied from class: OutputWriter

Writes a value to the output.

Specified by:

write in class OutputWriter<ByteBuffer>

Throws:

IOException

endShard

public void endShard()
              throws IOException

Closes the OutputChannel.

Overrides:

endShard in class ForwardingOutputWriter<ByteBuffer>

Throws:

IOException

getDelegate

protected OutputWriter<ByteBuffer> getDelegate()

Specified by:

getDelegate in class ForwardingOutputWriter<ByteBuffer>

getNumBlocksWritten

protected int getNumBlocksWritten()