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Apache Felix Dependency Manager
has been edited by Richard S. Hall
(Mar 09, 2008).
(View changes)
Content:
- Dependency Manager Introduction — In a service oriented architecture, applications consist of several cooperating services. These networks of services are often dynamic in nature, so managing dependencies is something the developer needs to take into account.
- Dependency Manager Design — The dependency manager is a dedicated component for managing dependencies. When using service trackers or listeners, a substantial amount of code needs to be written to track other services and act on changes. From a logical point of view, through a bundle you're managing one or more services. Each service can have zero or more dependencies that can either be required or optional. Required dependencies must be available before the service can even do its work, optional dependencies are used only if they're available.
- Dependency Manager Usage — Let's look at how to use this implementation. When developing an OSGi bundle that uses and possibly registers services, there are two classes in particular we need to implement. The first one is the bundle activator which controls the life-cycle of the bundle. The second one is the actual service implementation.
- Dependency Manager Background — There are a couple of concepts, explained here, that help understand the dependency manager better. This page lists them.
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