com.sun.grizzly.filter
Class CustomProtocolParser

java.lang.Object
  com.sun.grizzly.filter.CustomProtocolParser

All Implemented Interfaces:

ProtocolParser<MessageBase>

public class CustomProtocolParser
extends java.lang.Object
implements ProtocolParser<MessageBase>

Filter for parsing Messages of the CustomProtocol. The parsing is done in two stages.

First the Protocol Header bytes are read. With this an MessageBase is constructed Then the payload of the message is read and on completion a MessageBase is handled to the next Filter in the chain.

CustomProtocolParser tries to avoid byte copying. Therefore when a new Message has being parsed depending on its size and left space a ByteBuffer slice is created or the message takes ownership of the complete ByteBuffer and gives WorkerThread a completely new ByteBuffer.

Version:

1.0

Author:

John Vieten 21.06.2008

Field Summary

protected java.nio.ByteBuffer	byteBuffer
protected BytesTrafficListener	bytesArrivedListener
protected boolean	debug
protected boolean	expectingMoreData
protected boolean	hasMoreBytesToParse
protected MessageBase	msg
protected int	nextMsgStartPos
protected ReplyMessageFactory	replyMessageFactory
protected SSLConfig	sslConfig

Fields inherited from interface com.sun.grizzly.ProtocolParser

MESSAGE, PARSER

Constructor Summary

protected	CustomProtocolParser()
protected	CustomProtocolParser(SSLConfig sslConfig)

Method Summary

static ParserProtocolFilter	createParserProtocolFilter(BytesTrafficListener listener, ReplyMessageFactory replyInputStreamFactory, SSLConfig sslConfig) Since CustomProtocolParser is a statefull createParserProtocolFilter this indicates proper initilization.
MessageBase	getNextMessage() When getNextMessage() is called parser first has to check if anouther incomplete MessageBase is in the current ByteBuffer.
boolean	hasMoreBytesToParse() Are there more bytes to be parsed in the current ByteBuffer
boolean	hasNextMessage() Indicates whether the buffer has a complete message that can be returned from getNextMessage Basic algorithm : 1.
boolean	isExpectingMoreData() Does message need more bytes to be read in?
boolean	releaseBuffer() if this parser is expecting more bytes to be read then the current bytebuffer will not be released.
void	setBytesArrivedListener(BytesTrafficListener bytesArrivedListener)
void	setReplyMessageFactory(ReplyMessageFactory replyMessageFactory) Clients can be regsitered on a ReplyMessage The Factory holds to these Messages
void	startBuffer(java.nio.ByteBuffer byteBuffer) Gets called when new bytes have been added to the current ByteBuffer.

Methods inherited from class java.lang.Object

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

Field Detail

nextMsgStartPos

protected int nextMsgStartPos

hasMoreBytesToParse

protected boolean hasMoreBytesToParse

expectingMoreData

protected boolean expectingMoreData

msg

protected MessageBase msg

byteBuffer

protected java.nio.ByteBuffer byteBuffer

bytesArrivedListener

protected BytesTrafficListener bytesArrivedListener

replyMessageFactory

protected ReplyMessageFactory replyMessageFactory

debug

protected boolean debug

sslConfig

protected SSLConfig sslConfig

Constructor Detail

CustomProtocolParser

protected CustomProtocolParser()

CustomProtocolParser

protected CustomProtocolParser(SSLConfig sslConfig)

Method Detail

createParserProtocolFilter

public static ParserProtocolFilter createParserProtocolFilter(BytesTrafficListener listener,
                                                              ReplyMessageFactory replyInputStreamFactory,
                                                              SSLConfig sslConfig)

Since CustomProtocolParser is a statefull createParserProtocolFilter this indicates proper initilization.

Parameters:

listener - gets notified if a chunk of bytes arrives

replyInputStreamFactory - need for creating a replymessage

sslConfig - configures parser tob used wit SSL

Returns:

ParserProtocolFilter for creating CustomProtocolParser

getNextMessage

public MessageBase getNextMessage()

When getNextMessage() is called parser first has to check if anouther incomplete MessageBase is in the current ByteBuffer. If yes hasMoreBytesToParse() returns true and <@link CustomProtocolParser will get another chance to parse the current ByteBuffer starting at position nextMsgStartPos

The current MessageBase now takes ownership of a slice of the current ByteBuffer. By slicing the costs of an byte array copy are avoided.

Specified by:

getNextMessage in interface ProtocolParser<MessageBase>

Returns:

MessageBase the parsed Message

hasMoreBytesToParse

public boolean hasMoreBytesToParse()

Are there more bytes to be parsed in the current ByteBuffer

Specified by:

hasMoreBytesToParse in interface ProtocolParser<MessageBase>

Returns:

true if there are more bytes to be parsed. Otherwise false.

hasNextMessage

public boolean hasNextMessage()

Indicates whether the buffer has a complete message that can be returned from getNextMessage

Basic algorithm :

1. When in state no message check if there are enough bytes to parse the header. 1.1 If not check if there is enough space in ByteBuffer to hold the needed bytes. 1.1.1 If not create a new ByteBuffer with current header bytes. Remark: This should not happen very often so the copy is affordable. 1.1.2 return and isExpectingMoreData() should be true.

2. When no uncomplete message parse header and construct a new MessageBase 2.1 If more bytes are needed and ByteBuffer has enough space return and expect more bytes. 2.1.1 if not enough space hand MessageBase the current ByteBuffer and give Grizzly a new one and return and expect more bytes. 3. The ByteBuffer contains enough bytes to construct a complete MessageBase so parser does not expect more bytes and getNextMessage will be called.

Specified by:

hasNextMessage in interface ProtocolParser<MessageBase>

isExpectingMoreData

public boolean isExpectingMoreData()

Does message need more bytes to be read in?

Specified by:

isExpectingMoreData in interface ProtocolParser<MessageBase>

Returns:

- true if more bytes are needed to construct a message; false, if no additional bytes remain to be parsed into a T.

releaseBuffer

public boolean releaseBuffer()

if this parser is expecting more bytes to be read then the current bytebuffer will not be released. On the other hand if parser is done with bytebuffer then a new empty bytebuffer is handed to WorkerThread. Normally this would not be necessary but since MessageDispatcher is going to hand this byteBuffer to another Thread a new byteBuffer is given to WorkerThread

Specified by:

releaseBuffer in interface ProtocolParser<MessageBase>

startBuffer

public void startBuffer(java.nio.ByteBuffer byteBuffer)

Gets called when new bytes have been added to the current ByteBuffer.

Specified by:

startBuffer in interface ProtocolParser<MessageBase>

Parameters:

byteBuffer - the current ByteBuffer

setBytesArrivedListener

public void setBytesArrivedListener(BytesTrafficListener bytesArrivedListener)

Parameters:

bytesArrivedListener - a listener getting notified whene byte chunks arrive.

setReplyMessageFactory

public void setReplyMessageFactory(ReplyMessageFactory replyMessageFactory)

Clients can be regsitered on a ReplyMessage The Factory holds to these Messages

Parameters:

replyMessageFactory -