Package org.apache.hadoop.fs.store

Class DataBlocks.DataBlock

java.lang.Object

org.apache.hadoop.fs.store.DataBlocks.DataBlock

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable

Enclosing class:

DataBlocks

public abstract static class DataBlocks.DataBlock
extends java.lang.Object
implements java.io.Closeable

This represents a block being uploaded.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	DataBlocks.DataBlock.DestState

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	DataBlock(long index, BlockUploadStatistics statistics)

Method Summary

Modifier and Type	Method	Description
protected void	blockAllocated()	A block has been allocated.
protected void	blockReleased()	A block has been released.
void	close()
abstract int	dataSize()	Return the current data size.
protected boolean	enterClosedState()	Enter the closed state.
protected void	enterState(DataBlocks.DataBlock.DestState current, DataBlocks.DataBlock.DestState next)	Atomically enter a state, verifying current state.
void	flush()	Flush the output.
long	getIndex()
DataBlocks.DataBlock.DestState	getState()	Current state.
protected BlockUploadStatistics	getStatistics()
boolean	hasData()	Predicate to check if there is data in the block.
protected void	innerClose()	Inner close logic for subclasses to implement.
abstract int	remainingCapacity()	The remaining capacity in the block before it is full.
DataBlocks.BlockUploadData	startUpload()	Switch to the upload state and return a stream for uploading.
protected void	verifyState(DataBlocks.DataBlock.DestState expected)	Verify that the block is in the declared state.
int	write(byte[] buffer, int offset, int length)	Write a series of bytes from the buffer, from the offset.

Methods inherited from class java.lang.Object

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

Constructor Detail

DataBlock

protected DataBlock(long index,
                    BlockUploadStatistics statistics)

Method Detail

enterState

protected final void enterState(DataBlocks.DataBlock.DestState current,
                                DataBlocks.DataBlock.DestState next)
                         throws java.lang.IllegalStateException

Atomically enter a state, verifying current state.

Parameters:

current - current state. null means "no check"

next - next state

Throws:

java.lang.IllegalStateException - if the current state is not as expected

verifyState

protected final void verifyState(DataBlocks.DataBlock.DestState expected)
                          throws java.lang.IllegalStateException

Verify that the block is in the declared state.

Parameters:

expected - expected state.

Throws:

java.lang.IllegalStateException - if the DataBlock is in the wrong state

getState

public final DataBlocks.DataBlock.DestState getState()

Current state.

Returns:

the current state.

dataSize

public abstract int dataSize()

Return the current data size.

Returns:

the size of the data.

hasData

public boolean hasData()

Predicate to check if there is data in the block.

Returns:

true if there is

remainingCapacity

public abstract int remainingCapacity()

The remaining capacity in the block before it is full.

Returns:

the number of bytes remaining.

write

public int write(byte[] buffer,
                 int offset,
                 int length)
          throws java.io.IOException

Write a series of bytes from the buffer, from the offset. Returns the number of bytes written. Only valid in the state Writing. Base class verifies the state but does no writing.

Parameters:

buffer - buffer.

offset - offset.

length - length of write.

Returns:

number of bytes written.

Throws:

java.io.IOException - trouble

flush

public void flush()
           throws java.io.IOException

Flush the output. Only valid in the state Writing. In the base class, this is a no-op

Throws:

java.io.IOException - any IO problem.

startUpload

public DataBlocks.BlockUploadData startUpload()
                                       throws java.io.IOException

Switch to the upload state and return a stream for uploading. Base class calls enterState(DestState, DestState) to manage the state machine.

Returns:

the stream.

Throws:

java.io.IOException - trouble

enterClosedState

protected boolean enterClosedState()

Enter the closed state.

Returns:

true if the class was in any other state, implying that the subclass should do its close operations.

close

public void close()
           throws java.io.IOException

Specified by:

close in interface java.lang.AutoCloseable

Specified by:

close in interface java.io.Closeable

Throws:

java.io.IOException

innerClose

protected void innerClose()
                   throws java.io.IOException

Inner close logic for subclasses to implement.

Throws:

java.io.IOException - raised on errors performing I/O.

blockAllocated

protected void blockAllocated()

A block has been allocated.

blockReleased

protected void blockReleased()

A block has been released.

getStatistics

protected BlockUploadStatistics getStatistics()

getIndex

public long getIndex()