RE: [mina] Filter management (was Spring Integration)

[Niklas Therning]

From: Jose Alberto Fernandez [mailto:[EMAIL PROTECTED] Sent: den 10 november 2005 16:41 To: Apache Directory Developers List Subject: RE: [mina] Filter management (was Spring Integration)   Well, I hope you are right.   From: Trustin Lee [mailto:[EMAIL PROTECTED]   2a) Instead, insert ProtocolCodecFilter with your codec factory in your IoHandler.sessionCreated() method. For example: public void sessionCreated( IoSession session ) throws Exception {     session.getFilterChain().addFirst( "codec", new ProtocolCodecFilter( YOUR_CODEC_FACTORY ) ); } This is one place, where the approach I mentioned would make a lot of sense. You are running several protocols using several different handlers. You really do not want to specify on every session the adding of new CodecFilters, for example. You know all sessions will use the same filters and if your filters are stateless, they should be using the same one. It would make a lot of sense to be able to set this things once during bind() and not need to do it on every session creation.   (My reply) If I understand you correctly you want your IoHandler to implement IoFilterManager:   public class MyIoHandler implements IoHandler, IoFilterManager {     public void configureFilters(IoFilterChain chain) {         chain.addFirst( "codec", new ProtocolCodecFilter( YOUR_CODEC_FACTORY ) );     }     // Other IoHandler methods }   configureFilters will be called at bind-time.Of course the passed in IoFilterChain which is modified has to be local to that port you are binding to. Otherwise the next bind-call using another IoFilterManager and port will mess up the chain modified by the first call to bind. You can achieve exactly the same thing using a shared filter and Trustin’s approach above:   public class MyIoHandler implements IoHandler {     private ProtocolCodecFilter codecFilter = new ProtocolCodecFilter( YOUR_CODEC_FACTORY );   public void sessionCreated( IoSession session ) throws Exception {       session.getFilterChain().addFirst( "codec", codecFilter );   }     // Other IoHandler methods }   These two approaches look very similar to me. There’s really no difference. The same filter instance (which must be stateless) will be used anytime the same MyIoHandler instance is used.   You still need to know in your IoHandler/IoFilterManager how the filter chain should be modified which is exactly what I want to avoid. Let’s say I have a POP3Handler and want to support both SSL and non-SSL. With your approach I will have the make my POP3Handler implement IoFilterManager and somehow determine in configureFilters if the current bind is for the SLL or non-SSL port to know whether an SSLFilter should be added or not. I want my POP3Handler to be completely unaware of whether traffic is being encrypted or not. It doesn’t have to known that.   If you have an additional bind method where you may specify an IoFilterChain for that binding if will be quite easy to set up that chain using Spring.   BTW, I just realized that I have no idea whether SSLFilter is stateless or not. Is it?   /Niklas