| [cosmos-dev] SDD Eventing and the OSGi Whiteboard Pattern... |
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As a follow-up to my post yesterday about SDD classloading
and service registration, I’d like to also suggest that OSGi could be
leveraged to handle eventing and feedback using the Whiteboard pattern. “The whiteboard pattern
leverages the OSGi framework’s service registry instead of implementing a
private registry as required by the listener pattern. Instead of having event
listeners track event sources and then register themselves with the event
source, the whiteboard pattern has event listeners register themselves as a
service with the OSGi framework. When the event source has an event object to
deliver, the event source calls all event listeners in the service registry. Remarkably, the event source is not
registered with the framework as a service. This makes bundles using the
whiteboard pattern significantly smaller and easier to implement. The
inter-bundle dependency between the event source and the event listener is
handled by the framework and requires almost no code in the event source and
event listener bundles.” -from
http://www.osgi.org/wiki/uploads/Links/whiteboard.pdf -Brad Bradley Beck |