tachyon.worker

Class DataServerMessage

java.lang.Object

tachyon.worker.DataServerMessage

public final class DataServerMessage
extends Object

The message type used to send data request and response for remote data.

Method Summary

Methods

Modifier and Type	Method and Description
void	checkReady() Checks if the message is ready.
void	close() Closes the message.
static DataServerMessage	createBlockRequestMessage() Creates a default block request message, just allocates the message header, and no attribute is set.
static DataServerMessage	createBlockRequestMessage(long blockId) Creates a block request message for an entire block by the block id, and the message is ready to be sent.
static DataServerMessage	createBlockRequestMessage(long blockId, long offset, long len) Creates a block request message for a part of the block by the block id, the offset and the length.
static DataServerMessage	createBlockResponseMessage(boolean toSend, long blockId, ByteBuffer data) Creates a block response message specified by the block's id.
static DataServerMessage	createBlockResponseMessage(boolean toSend, long blockId, long offset, long len, ByteBuffer data) Creates a block response message specified by the block's id, the offset and the length.
boolean	finishSending() Returns whether the message finishes sending or not.
long	getBlockId() Gets the id of the block.
long	getLength() Gets the length of the message's requested or responded data.
long	getLockId() Gets the id of the block's locker.
long	getOffset() Gets the offset of the message's data in the block.
ByteBuffer	getReadOnlyData() Gets the read only buffer of the message's data.
RPCResponse.Status	getStatus() Gets the status of the response.
boolean	isMessageReady()
int	recv(SocketChannel socketChannel) Use this message to receive from the specified socket channel.
void	send(SocketChannel socketChannel) Sends this message to the specified socket channel.
void	setLockId(long lockId) Sets the id of the block's locker.

Methods inherited from class java.lang.Object

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

Method Detail

createBlockRequestMessage

public static DataServerMessage createBlockRequestMessage()

Creates a default block request message, just allocates the message header, and no attribute is set. The message is not ready to be sent.

Returns:

the created block request message

createBlockRequestMessage

public static DataServerMessage createBlockRequestMessage(long blockId)

Creates a block request message for an entire block by the block id, and the message is ready to be sent.

Parameters:

blockId - The id of the block

Returns:

The created block request message

createBlockRequestMessage

public static DataServerMessage createBlockRequestMessage(long blockId,
                                          long offset,
                                          long len)

Creates a block request message for a part of the block by the block id, the offset and the length. The message is ready to be sent. If len is -1, it means requesting the data from offset to the end of the block.

Parameters:

blockId - The id of the block

offset - The requested data's offset in the block

len - The length of the requested data. If it's -1, it means request the data from offset to the block's end.

Returns:

The created block request message

createBlockResponseMessage

public static DataServerMessage createBlockResponseMessage(boolean toSend,
                                           long blockId,
                                           ByteBuffer data)

Creates a block response message specified by the block's id. If toSend is true, it will prepare the data to be sent, otherwise the message is used to receive data.

Parameters:

toSend - If true the message is to send the data, otherwise it's used to receive data.

blockId - The id of the block

data - The data of the message

Returns:

The created block response message

createBlockResponseMessage

public static DataServerMessage createBlockResponseMessage(boolean toSend,
                                           long blockId,
                                           long offset,
                                           long len,
                                           ByteBuffer data)

Creates a block response message specified by the block's id, the offset and the length. If toSend is true, it will prepare the data to be sent, otherwise the message is used to receive data. If len is -1, it means response the data from offset to the block's end.

Parameters:

toSend - If true the message is to send the data, otherwise it's used to receive data

blockId - The id of the block

offset - The responded data's offset in the block

len - The length of the responded data. If it's -1, it means respond the data from offset to the block's end.

data - The data of the message

Returns:

The created block response message

checkReady

public void checkReady()

Checks if the message is ready. If not ready, it will throw a runtime exception.

close

public void close()

Closes the message.

finishSending

public boolean finishSending()

Returns whether the message finishes sending or not. It will check if the message is a send message, so don't call this on a recv message.

Returns:

true if the message finishes sending, false otherwise

getBlockId

public long getBlockId()

Gets the id of the block. Make sure the message is ready before calling this method.

Returns:

The id of the block

getLength

public long getLength()

Gets the length of the message's requested or responded data. Make sure the message is ready before calling this method.

Returns:

The length of the message's requested or responded data

getLockId

public long getLockId()

Gets the id of the block's locker.

Returns:

The id of the block's locker

getOffset

public long getOffset()

Gets the offset of the message's data in the block. Make sure the message is ready before calling this method.

Returns:

The offset of the message's data in the block

getStatus

public RPCResponse.Status getStatus()

Gets the status of the response. Make sure the message is ready before calling this method.

Returns:

The RPCResponse.Status of the response

getReadOnlyData

public ByteBuffer getReadOnlyData()

Gets the read only buffer of the message's data. Make sure the message is ready before calling this method.

Returns:

The read only buffer of the message's data

isMessageReady

public boolean isMessageReady()

Returns:

true if the message is ready, false otherwise

recv

public int recv(SocketChannel socketChannel)
         throws IOException

Use this message to receive from the specified socket channel. Make sure this is a recv message and the message type is matched.

Parameters:

socketChannel - The socket channel to receive from

Returns:

The number of bytes read, possibly zero, or -1 if the channel has reached end-of-stream

Throws:

IOException

send

public void send(SocketChannel socketChannel)
          throws IOException

Sends this message to the specified socket channel. Make sure this is a send message.

Parameters:

socketChannel - The socket channel to send to

Throws:

IOException

setLockId

public void setLockId(long lockId)

Sets the id of the block's locker.

Parameters:

lockId - The id of the block's locker