com.sun.grizzly
Interface ProtocolParser<T>

public interface ProtocolParser<T>

An interface that knows how to parse bytes into a protocol data unit.

Author:

Charlie Hunt

Field Summary

static String	MESSAGE Holds the message returned from getNextMessage for use by downstream filters
static String	PARSER Used to associate a particular parser with a connection

Method Summary

T	getNextMessage() Get the next complete message from the buffer, which can then be processed by the next filter in the protocol chain.
boolean	hasMoreBytesToParse() Are there more bytes to be parsed in the ByteBuffer given to this ProtocolParser's ProtocolParser#startBuffer() ? This method is typically called after processing the protocol message, to determine if the ByteBuffer has more bytes which need to parsed into a next message.
boolean	hasNextMessage() Indicates whether the buffer has a complete message that can be returned from getNextMessage().
boolean	isExpectingMoreData() Is this ProtocolParser expecting more data ? This method is typically called after a call to hasNextMessage() to determine if the ByteBuffer which has been parsed contains a partial message
boolean	releaseBuffer() No more parsing will be done on the buffer passed to ProtocolParser#startBuffer().
void	startBuffer(ByteBuffer bb) Set the buffer to be parsed.

Field Detail

PARSER

static final String PARSER

Used to associate a particular parser with a connection

See Also:

Constant Field Values

MESSAGE

static final String MESSAGE

Holds the message returned from getNextMessage for use by downstream filters

See Also:

Constant Field Values

Method Detail

isExpectingMoreData

boolean isExpectingMoreData()

Is this ProtocolParser expecting more data ? This method is typically called after a call to hasNextMessage() to determine if the ByteBuffer which has been parsed contains a partial message

Returns:

- true if more bytes are needed to construct a message; false, if no additional bytes remain to be parsed into a protocol data unit. Note that if no partial message exists, this method should return false.

hasMoreBytesToParse

boolean hasMoreBytesToParse()

Are there more bytes to be parsed in the ByteBuffer given to this ProtocolParser's ProtocolParser#startBuffer() ? This method is typically called after processing the protocol message, to determine if the ByteBuffer has more bytes which need to parsed into a next message.

Returns:

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

getNextMessage

T getNextMessage()

Get the next complete message from the buffer, which can then be processed by the next filter in the protocol chain. Because not all filters will understand protocol messages, this method should also set the position and limit of the buffer at the start and end boundaries of the message. Filters in the protocol chain can retrieve this message via context.getAttribute(MESSAGE)

Returns:

The next message in the buffer. If there isn't such a message, return null.

hasNextMessage

boolean hasNextMessage()

Indicates whether the buffer has a complete message that can be returned from getNextMessage(). Smart implementations of this will set up all the information so that an actual call to getNextMessage() doesn't need to re-parse the data.

startBuffer

void startBuffer(ByteBuffer bb)

Set the buffer to be parsed. This method should store the buffer and its state so that subsequent calls to getNextMessage() will return distinct messages, and the buffer can be restored after parsing when the releaseBuffer() method is called.

releaseBuffer

boolean releaseBuffer()

No more parsing will be done on the buffer passed to ProtocolParser#startBuffer(). Set up the buffer so that its position is the first byte that was not part of a full message, and its limit is the original limit of the buffer.

Returns:

-- true if the parser has saved some state (e.g. information data in the buffer that hasn't been returned in a full message); otherwise false. If this method returns true, the framework will make sure that the same parser is used to process the buffer after more data has been read.