Package aQute.bnd.annotation

Annotation Interface ProviderType

@Documented
@Retention(CLASS)
@Target(TYPE)
public @interface ProviderType

A change in a provider type (that is all except Consumer types) can be changed with only (at minimum) a minor update to the package API version number. This interface is similar to the Eclipse @noextend and @noimplement annotations. OSGi specifications use the @noimplement annotation, see below.

Elaborate and Simple Explanation

There is a distinction between "provider implemented" and "consumer implemented" interfaces, which is reflected in the ProviderType and ConsumerType annotations respectively.

These annotations can be placed on an interface to enable the tooling to detect the role of the interface and generate the correct import range.

Usually - to a developer - the role of the interface is clear: interfaces that are merely call-backs or listeners are generally "consumer implemented".

Thought Experiment with ConfigurationAdmin

In the case of the ConfigurationAdmin specification: implementing ManagedService or ManagedServiceFactory does not make you a provider. You would have to implement ConfigurationAdmin in order to be a provider.

Rule of thumb: suppose a method would be added to ManagedServiceFactory. How many bundles would be broken as a result? The answer is "lots" and therefore ManagedServiceFactory is a consumer type. However, if a method would be added to ConfigurationAdmin then only a very small number of bundles would be broken; these are the providers of the ConfigurationAdmin API, e.g. org.apache.felix.configadmin and so on.

Relation to OSGi Specifications and Javadoc

At OSGi, the javadoc tag @noimplement is used to mark "provider implemented" interfaces. Interfaces not marked @noimplement are "consumer implemented" interfaces.

So, for example, the ConfigurationAdmin interface is marked @noimplement while the ManagedService and ManagedServiceFactory interfaces are not.

In the specification, you will see "No Implement Consumers of this API must not implement this interface" for @noimplement marked interfaces.

In the html javadoc, you will see "Consumers of this API must not implement this interface" for @noimplement marked interfaces.