On Tue, 2006-05-09 at 11:19 +0900, Trustin Lee wrote:
> On 5/9/06, Frederic Soulier <[EMAIL PROTECTED]> wrote:
> >
> > Ok so I can achieve what I think the Demuxing stuff was doing by
> > having 2 ProtocolCodecFactory registered in the filter chain.
> >
> > "codec1"
> > ProtocolCodecFactory_1
> > encoder1
> > decoder1
> >
> > "codec2"
> > ProtocolCodecFactory_2
> > encoder2
> > decoder2
> >
> > builder.addFirst("filter1", new ProtocolCodecFilter(codec1));
> > builder.addLast("filter2", new ProtocolCodecFilter(codec2));
> >
> > In that case:
> > decoder1 writes to ProtocolDecoderOutput -> decoder2
> > encoder1 writes to ProtocolEncoderOutput -> encoder2
> > or is it symetrical?
> > decoder1 writes to ProtocolDecoderOutput -> decoder2
> > encoder2 writes to ProtocolEncoderOutput -> encoder1
> >
> > Is that correct?
>
>
> Encoding is done exactly in the reversed order. So the latter is the
> correct answer. :)
>
> The one thing you have to note is that decoders will bypass non-ByteBuffers,
> and encoders will bypass ByteBuffers by its nature.
Thx Trustin.
I know it's been re-hashed to death but I'd like to clarify some
stuff :) I also went through the archives which prompted even more
question marks (lol).
"codec1" (ProtocolCodecFactory_1)
decoder1
encoder1
"codec2" (ProtocolCodecFactory_2)
decoder2
encoder2
"codec3" (ProtocolCodecFactory_3)
decoder3
encoder3
builder.addFirst("filter1", new ProtocolCodecFilter(codec1));
builder.addAfter("filter1", "filter2", new ProtocolCodecFilter(codec2));
builder.addLast("filter3", new ProtocolCodecFilter(codec3));
So in that configuration, I have in order:
decoder1 -> decoder2 -> decoder3 -> IoHandler
encoder3 -> encoder2 -> encoder1
(Decoders)
In order for the chain of decoders to be executed properly decoder1 must
feed a ByteBuffer to decoder2 which must feed a ByteBuffer to decoder3
which can write anything; it will end up in messageReceived if the
IoHandler.
If decoder1 doesn't write a ByteBuffer then decoder2 and decoder3 are
completely bypassed and whatever decoder1 wrote on ProtocolDecoderOutput
ends up in the messageReceived of the IoHandler.
Am I right so far?
When moving from one decoder to the next one I'm planning to allocate a
new ByteBuffer and pass it onto the next decoder.
decoder1
- do something with incoming ByteBuffer
- allocate new ByteBuffer and copy whatever I need
- write ByteBuffer to out and move onto decoder2
decoder2
- do something with incoming ByteBuffer
- allocate new ByteBuffer and copy whatever I need
- write ByteBuffer to out and move onto decoder3
decoder3
- do something with incoming ByteBuffer
- allocate new ByteBuffer and copy whatever I need
- write <something> that ends up in the IoHandler
messageReceived() method
(Encoders)
If I write a message (Object) using the IoSession.write(Object) method
then encoder3 receives the message. Right?
If I write a ByteBuffer using the IoSession.write(Object) method then
the whole chain of encoders is bypassed. Right?
If I write a message (Object) using the IoSession.write(Object) method
then encoder3 receives the message. Now I can only write a ByteBuffer
using ProtocolEncoderOutput.write(ByteBuffer) so isn't that going to
bypass the remaining encoders?
I don't understand how to chain the encoders.
Note that I have all this working fine with just 1 decoder and 1 encoder
but we'd like to take a layered approach to decode/encode our message
protocol hence the above.
Thx.
--
Frederic Soulier <[EMAIL PROTECTED]>
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