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From "Alex Karasulu" <>
Subject [RT] Notification pattern has interesting effects on IoC
Date Wed, 18 Feb 2004 04:44:16 GMT
Hi all,

While looking at the frontend of the Eve server I began to realize a trend
emerging after I introduced a central publish and subscribe facility. The
pattern decouples components by enabling communication using events and the
notifier pattern. This also lead to the disappearence of methods on service

So the dependency graph turns into a star with all components depending on
the event router, hub, bus or whatever you call it in the center. Event
types and interfaces essentially become the dependency as opposed to the
service interfaces. This way you can introduce new subscribers and
publishers. Also the dynamic rerouting of events is possible at runtime.
What this means is that the dependencies between components can change on
the fly! Wow not a bad thang. 

What does this mean for service interfaces? Well they start looking bleak
because the Subscriber interface replaces them. Basically methods are called
internally by the Subscriber handling code on the component itself rather
than exposing them on the service interface for direct calls by what are now
publishers. This is crazy my service interfaces are all empty now! 


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