alluxio.worker.block

Class RemoteBlockReader

java.lang.Object

alluxio.worker.block.RemoteBlockReader

All Implemented Interfaces:

BlockReader, Closeable, AutoCloseable

public class RemoteBlockReader
extends Object
implements BlockReader

Reads a block from a remote worker node. This should only be used for reading entire blocks.

Constructor Summary

Constructors

Constructor and Description
RemoteBlockReader(FileSystemContext fsContext, long blockId, long blockSize, InetSocketAddress dataSource, Protocol.OpenUfsBlockOptions ufsOptions) Constructs a remote block reader.

Method Summary

Modifier and Type	Method and Description
void	close()
ReadableByteChannel	getChannel() Returns a readable byte channel of the block.
long	getLength() Gets the length of the block in bytes.
boolean	isClosed()
ByteBuffer	read(long offset, long length) Reads data from the block.
int	transferTo(io.netty.buffer.ByteBuf buf) Transfers data (up to buf.writableBytes()) from this reader to the buffer.

Methods inherited from class java.lang.Object

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

Constructor Detail

RemoteBlockReader

public RemoteBlockReader(FileSystemContext fsContext,
                         long blockId,
                         long blockSize,
                         InetSocketAddress dataSource,
                         Protocol.OpenUfsBlockOptions ufsOptions)

Constructs a remote block reader. It will read from a remote worker based on the data source.

Parameters:

fsContext - the filesystem context to use to create BlockInStream

blockId - the block to cache

blockSize - the size of the block

dataSource - the data source to cache from

ufsOptions - the options to read the block from ufs if necessary

Method Detail

read

public ByteBuffer read(long offset,
                       long length)
                throws IOException

Description copied from interface: BlockReader

Reads data from the block.

Specified by:

read in interface BlockReader

Parameters:

offset - the offset from starting of the block file in bytes

length - the length of data to read in bytes, -1 for the rest of the block

Returns:

ByteBuffer the data that was read

Throws:

IOException

getLength

public long getLength()

Description copied from interface: BlockReader

Gets the length of the block in bytes.

Specified by:

getLength in interface BlockReader

Returns:

the length of the block in bytes

getChannel

public ReadableByteChannel getChannel()

Description copied from interface: BlockReader

Returns a readable byte channel of the block.

Specified by:

getChannel in interface BlockReader

Returns:

channel

transferTo

public int transferTo(io.netty.buffer.ByteBuf buf)
               throws IOException

Description copied from interface: BlockReader

Transfers data (up to buf.writableBytes()) from this reader to the buffer.

Specified by:

transferTo in interface BlockReader

Parameters:

buf - the byte buffer

Returns:

the number of bytes transferred, -1 if the end of the block is reached

Throws:

IOException

isClosed

public boolean isClosed()

Specified by:

isClosed in interface BlockReader

Returns:

true if this reader is closed

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Throws:

IOException