io.undertow.websockets.extensions

Class PerMessageDeflateFunction

java.lang.Object

io.undertow.websockets.extensions.PerMessageDeflateFunction

All Implemented Interfaces:

ExtensionFunction

public class PerMessageDeflateFunction
extends Object
implements ExtensionFunction

Implementation of permessage-deflate WebSocket Extension.

This implementation supports parameters: server_no_context_takeover, client_no_context_takeover .

This implementation does not support parameters: server_max_window_bits, client_max_window_bits .

It uses the DEFLATE implementation algorithm packaged on Deflater and Inflater classes.

Author:

Lucas Ponce

See Also:

Compression Extensions for WebSocket

Field Summary

Fields

Modifier and Type	Field and Description
static byte[]	TAIL

Fields inherited from interface io.undertow.websockets.extensions.ExtensionFunction

RSV1, RSV2, RSV3

Constructor Summary

Constructors

Constructor and Description
PerMessageDeflateFunction(int deflaterLevel, boolean compressContextTakeover, boolean decompressContextTakeover) Create a new PerMessageDeflateExtension instance.

Method Summary

Modifier and Type	Method and Description
void	dispose() Dispose this function.
boolean	hasExtensionOpCode() Validate if current extension defines a new WebSocket Opcode.
PooledByteBuffer	transformForRead(PooledByteBuffer pooledBuffer, WebSocketChannel channel, boolean lastFragmentOfFrame) Transform the supplied buffer per this extension.
PooledByteBuffer	transformForWrite(PooledByteBuffer pooledBuffer, WebSocketChannel channel) Transform the supplied buffer per this extension.
int	writeRsv(int rsv) Add RSV bits (RSV1, RSV2, RSV3) to the current rsv status.

Methods inherited from class java.lang.Object

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

Field Detail

TAIL

public static final byte[] TAIL

Constructor Detail

PerMessageDeflateFunction

public PerMessageDeflateFunction(int deflaterLevel,
                                 boolean compressContextTakeover,
                                 boolean decompressContextTakeover)

Create a new PerMessageDeflateExtension instance.

Parameters:

deflaterLevel - the level of configuration of DEFLATE algorithm implementation

compressContextTakeover - flag for compressor context takeover or without compressor context

decompressContextTakeover - flag for decompressor context takeover or without decompressor context

Method Detail

writeRsv

public int writeRsv(int rsv)

Description copied from interface: ExtensionFunction

Add RSV bits (RSV1, RSV2, RSV3) to the current rsv status.

Specified by:

writeRsv in interface ExtensionFunction

Parameters:

rsv - current RSV bits status

Returns:

rsv status

hasExtensionOpCode

public boolean hasExtensionOpCode()

Description copied from interface: ExtensionFunction

Validate if current extension defines a new WebSocket Opcode.

Specified by:

hasExtensionOpCode in interface ExtensionFunction

Returns:

true if current extension defines specific Opcode false is current extension does not define specific Opcode

See Also:

WebSocket Base Framing Protocol Reference

transformForWrite

public PooledByteBuffer transformForWrite(PooledByteBuffer pooledBuffer,
                                          WebSocketChannel channel)
                                   throws IOException

Description copied from interface: ExtensionFunction

Transform the supplied buffer per this extension. The buffer can be modified in place, or a new pooled buffer can be returned (in which case be sure to free the original buffer

Specified by:

transformForWrite in interface ExtensionFunction

Parameters:

pooledBuffer - Buffer to transform

channel - working channel

Returns:

transformed buffer (may be the same one, just with modified contents)

Throws:

IOException

transformForRead

public PooledByteBuffer transformForRead(PooledByteBuffer pooledBuffer,
                                         WebSocketChannel channel,
                                         boolean lastFragmentOfFrame)
                                  throws IOException

Description copied from interface: ExtensionFunction

Transform the supplied buffer per this extension. The buffer can be modified in place, or a new pooled buffer can be returned (in which case be sure to free the original buffer

Specified by:

transformForRead in interface ExtensionFunction

Parameters:

pooledBuffer - Buffer to transform

channel - working channel

Returns:

transformed buffer (may be the same one, just with modified contents)

Throws:

IOException

dispose

public void dispose()

Description copied from interface: ExtensionFunction

Dispose this function. Called upon connection closure

Specified by:

dispose in interface ExtensionFunction