Code structure

The class needs to implement the IPlugin interface to be a plugin. This is just the init() method and the shutdown() method. It also implements two methods for the ISimpleServiceProvider interface.

By implementing ISimpleServiceProvider it can be added to a ServiceManager which acts as a collection point for all plugins which provide services and which is itself a plugin manager.

Thus every plugin implements IPlugin, to enable it to be added to a plugin manager, and at least one other interface to perform its specific task.