On 9/29/06, oscar 12321 <[EMAIL PROTECTED]> wrote:
I have a complex protocol to implement and I have started modifying the
sumup example.
My protocol consists of messages all of then sent in and envelope like
this:
4 bytes: size of data
N bytes: the data
1 byte: tail mark.
Then each message inside the envelope (the data), contains a header byte
with the type of message flllowed by the rest of fields of the message.
My question is: should i implement a stack of two protocol filters, one
for
the envelope (like the TextLineCodec), and other for the message data
itself
(perhaps a DemuxingProtocolCodec)?
You just need one codec and one custom filter instead of two codecs:
1. Codec translates the message into an intermediary message.
2. Your filter translates the intermediary message (the data, envelope) into
the final message object.
Implementing a filter is very easy, so you will be able to implement the
translator shortly.
...
void messageReceived(NextFilter next, IoSession session, Object message) {
IntermediaryMessage m = (IntermediaryMessage) message;
ByteBuffer buf = m.getContent();
... do something with the buf ...
next.messageReceived(session, newMessage);
}
...
HTH,
Trustin
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