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From "Alex Karasulu" <>
Subject Re: [ApacheDS] Cost of interceptors / BindHandler Chain as an example ...
Date Fri, 01 Jun 2007 15:12:06 GMT
On 5/31/07, Emmanuel Lecharny <> wrote:
> Hi guys,
> as a perfect exemple of what I wrote about interceptors, I can use the
> BindHandler chain to exhibit some of the problems this pattern
> carries.
> 1) Debugging nightmare : The BindHandler chain is a composition of 6
> handlers. When commuting from one handler to the next one, you have to
> pass through 4 levels of calls into MINA (which means if you don't
> have the sources, your are blind). The only way to step through those
> handlers is to *know* which is next into the chain, and as this chain
> is supposed to be dynamic (at least theorically), can be more than
> tricky. And in this case, you will have to set 7 breakpoints...

Yes I don't like this at all.  I was not going to allow the merge with this
code but I let it
pass this time since it can be refactored out later.  This pattern is being
used far excessively
like a sledge hammer on finishing nails and as you state debugging it is a

2) If you are using Simple authentication, you must go through SASL
> configuration and handling. Costly ...
> 3) the order in which the handler are called will never change : (1)
> check the parameters, (2) handle the authenticator, (3) get the
> context (4) process to the bind operation (5) return the result. In
> this case, we could perectly avoid using a chaining pattern


At some point, I think that we should discuss the chosen
> implementation and architecture before going for a complex choice, as
> soon as it does not freeze the developpement into a net of mails and
> IRC convo so tight that no code get out of this net.


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