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From Grzegorz Kossakowski <>
Subject Re: [C3] Pipeline component event types
Date Tue, 13 Jan 2009 12:38:13 GMT
Reinhard Pötz wrote:
> I don't believe that pipelines should contain components that support
> different event types or that we event need components that have
> different input and output events.
What about serializer? Usually, it produces events of a type different
from the type of events it consumes.
> If you want to mix your components (e.g. using a SAX component in a
> pipeline full of StAX components), you should put your 'alien' component
> into a wrapper.
Agreed. How do you know what kind of wrapper do you need if you don't
know what kind of events components consume and produce?

How component can be sure that next component (its consumer) is the one
that accepts right type of events? By checking using instanceof?
My point is that once we agree to have generic pipelines that can take
components accepting/producing any kind of events then we need to invent
some mechanism that check if pipeline is built correctly. It shouldn't
be a concern of a given component.

If we agree on above point, then my suggestion would be to look for a
way that pipeline-correctness is ensured by compiler.

Best regards,
Grzegorz Kossakowski

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