com.yahoo.fs4

Class BasicPacket

java.lang.Object

com.yahoo.fs4.BasicPacket

Direct Known Subclasses:

Packet, PingPacket, PongPacket

public abstract class BasicPacket
extends Object

Superclass of fs4 packets

Author:

bratseth

Field Summary

Fields

Modifier and Type	Field and Description
static int	CODE_MASK
private int	compressionLimit
private com.yahoo.compress.CompressionType	compressionType
private com.yahoo.compress.Compressor	compressor
private static int	DEFAULT_WRITE_BUFFER_SIZE
protected byte[]	encodedBody
protected ByteBuffer	encodingBuffer
protected int	length The length of this packet in bytes or -1 if not known
private static Logger	log
private long	timeStamp A timestamp which can be set or inspected by clients of this class but which is never updated by the class itself.

Constructor Summary

Constructors

Constructor and Description
BasicPacket()

Method Summary

Modifier and Type	Method and Description
void	allocateAndEncode(int channelId) Allocate the needed buffers and encode the packet using the given channel ID (if pertinent).
private void	allocateAndEncode(int channelId, int initialSize)
protected void	codeDecodedHook(int code) Called when the packet code is decoded.
BasicPacket	decode(ByteBuffer buffer) Fills this package from a byte buffer positioned at the first byte of the package
protected void	decodeAndDecompressBody(ByteBuffer buffer, int code, int packetLength)
void	decodeBody(ByteBuffer buffer) Decodes the body of this package from a byte buffer positioned at the first byte of the package.
BasicPacket	encode(ByteBuffer buffer) Encodes this package onto the given buffer at the current position.
Packet	encode(ByteBuffer buffer, int channel) Just a place holder to make the APIs simpler.
protected void	encodeAndCompressBody(ByteBuffer buffer, int startPosition)
protected void	encodeBody(ByteBuffer buffer) Encodes the body of this package onto the given buffer at the current position.
abstract int	getCode() Returns the code of this package
private int	getCompressedCode(com.yahoo.compress.CompressionType compression)
int	getLength() Returns the length of this body (including header (8 bytes) and body), or -1 if not known.
long	getTimestamp() Get the timestamp field of this packet.
ByteBuffer	grantEncodingBuffer(int channelId) Return buffer containing the encoded form of this package and remove internal reference to it.
ByteBuffer	grantEncodingBuffer(int channelId, int initialSize)
boolean	hasChannelId() Whether this is a packets which can encode a channel ID.
boolean	isEncoded()
protected void	patchChannelId(ByteBuffer buf, int channelId)
void	setCompressionLimit(int limit) Sets the number of bytes the package must be before activating compression.
void	setCompressionType(String type)
protected void	setEncodedBody(ByteBuffer b, int start, int length)
void	setTimestamp(long timeStamp) Set the timestamp field of the packet.
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

compressor

private final com.yahoo.compress.Compressor compressor

log

private static Logger log

DEFAULT_WRITE_BUFFER_SIZE

private static int DEFAULT_WRITE_BUFFER_SIZE

CODE_MASK

public static final int CODE_MASK

See Also:

Constant Field Values

encodedBody

protected byte[] encodedBody

encodingBuffer

protected ByteBuffer encodingBuffer

length

protected int length

The length of this packet in bytes or -1 if not known

timeStamp

private long timeStamp

A timestamp which can be set or inspected by clients of this class but which is never updated by the class itself. This is mostly a convenience for when you need to queue packets or retain them in some structure where their validity is limited by a timeout or similar.

compressionLimit

private int compressionLimit

compressionType

private com.yahoo.compress.CompressionType compressionType

Constructor Detail

BasicPacket

public BasicPacket()

Method Detail

setCompressionLimit

public void setCompressionLimit(int limit)

Sets the number of bytes the package must be before activating compression. A value of 0 means no compression.

Parameters:

limit - smallest package size that triggers compression.

setCompressionType

public void setCompressionType(String type)

decode

public BasicPacket decode(ByteBuffer buffer)

Fills this package from a byte buffer positioned at the first byte of the package

Returns:

this for convenience

Throws:

UnsupportedOperationException - if not implemented in the subclass

decodeAndDecompressBody

protected void decodeAndDecompressBody(ByteBuffer buffer,
                                       int code,
                                       int packetLength)

decodeBody

public void decodeBody(ByteBuffer buffer)

Decodes the body of this package from a byte buffer positioned at the first byte of the package.

Throws:

UnsupportedOperationException - if not implemented in the subclass

codeDecodedHook

protected void codeDecodedHook(int code)

Called when the packet code is decoded. This default implementation just throws an exception if the code is not the code of this packet. Packets which has several possible codes will use this method to store the code.

encode

public BasicPacket encode(ByteBuffer buffer)
                   throws BufferTooSmallException

Encodes this package onto the given buffer at the current position. The position of the buffer after encoding is the byte following the last encoded byte.

This method will ensure that everything is written provided sufficient capacity regardless of the buffer limit. When returning, the limit is at the end of the package (qual to the position).

Returns:

this for convenience

Throws:

UnsupportedOperationException - if not implemented in the subclass

BufferTooSmallException

encodeAndCompressBody

protected void encodeAndCompressBody(ByteBuffer buffer,
                                     int startPosition)

getCompressedCode

private int getCompressedCode(com.yahoo.compress.CompressionType compression)

encodeBody

protected void encodeBody(ByteBuffer buffer)

Encodes the body of this package onto the given buffer at the current position. The position of the buffer after encoding is the byte following the last encoded byte.

Throws:

UnsupportedOperationException - if not implemented in the subclass

setEncodedBody

protected void setEncodedBody(ByteBuffer b,
                              int start,
                              int length)

isEncoded

public boolean isEncoded()

encode

public Packet encode(ByteBuffer buffer,
                     int channel)
              throws BufferTooSmallException

Just a place holder to make the APIs simpler.

Throws:

BufferTooSmallException

allocateAndEncode

public final void allocateAndEncode(int channelId)

Allocate the needed buffers and encode the packet using the given channel ID (if pertinent). If this packet does not use a channel ID, the ID will be ignored.

allocateAndEncode

private void allocateAndEncode(int channelId,
                               int initialSize)

patchChannelId

protected void patchChannelId(ByteBuffer buf,
                              int channelId)

grantEncodingBuffer

public final ByteBuffer grantEncodingBuffer(int channelId)

Return buffer containing the encoded form of this package and remove internal reference to it.

grantEncodingBuffer

public final ByteBuffer grantEncodingBuffer(int channelId,
                                            int initialSize)

getCode

public abstract int getCode()

Returns the code of this package

getLength

public int getLength()

Returns the length of this body (including header (8 bytes) and body), or -1 if not known. Note that the streamed packet format length is 4 bytes less than this length, for unknown reasons. The length is always known when decodeBody is called.

setTimestamp

public void setTimestamp(long timeStamp)

Set the timestamp field of the packet. A timestamp which can be set or inspected by clients of this class but which is never updated by the class itself. This is mostly a convenience for when you need to queue packets or retain them in some structure where their validity is limited by a timeout or similar.

getTimestamp

public long getTimestamp()

Get the timestamp field of this packet. Note that this is not part of the FS4 protocol. @see #setTimestamp for more information

toString

public String toString()

Overrides:

toString in class Object

hasChannelId

public boolean hasChannelId()

Whether this is a packets which can encode a channel ID.