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
--
what we call human nature is actually human habit
--
http://gleamynode.net/
--
PGP key fingerprints:
* E167 E6AF E73A CBCE EE41 4A29 544D DE48 FE95 4E7E
* B693 628E 6047 4F8F CFA4 455E 1C62 A7DC 0255 ECA6
Hi Trustin,
I have done it and its working for the received messages, but when i whant
to send a message, the filter is ignored and goes directly to the codec. It
seems that the chain is working well for received messages but not for
outgoing ones.
I create the chain in the session handler like this:
ProtocolCodecFactory codec = MyCodecFactory(); // The envelope codec factory
session.getFilterChain().addFirst("protocolFilter", new
ProtocolCodecFilter(codec));
session.getFilterChain().addLast("messageFilter", new MessageFilter());
The codec is working well by removing or adding the envelope, but the filter
is only working for received messages.
I have suibclassed it from "IoFilterAdapter" and override the
"messageReceived" and "messageSent". But "MessageSent" its never called,
instead the encoder is called directly.
Any Idea?
Thanks
_________________________________________________________________
¿Estás pensando en cambiar de coche? Todas los modelos de serie y extras en
MSN Motor. http://motor.msn.es/researchcentre/
