@Retention(value=RUNTIME) @Target(value={TYPE,FIELD}) @RequestScoped @Documented public @interface Provides
Indicates that a class provides one or more services. By default, all the declared interfaces of the class are considered to be services provided by the class. If the class does not implement any interfaces then the service being offered is the class itself.
Classes annotated with Provides
are discoverable by the Dependency Injection framework.
If necessary the set of services provided by a type can be explicitly specified using the value()
property.
@Provides class Foo { ... }
Since Foo
does not implement any interfaces then it provides itself as a service.
@Provides class Foo implements Bar { ... }
Foo
provides the service Bar
.
@Provides({Bar.class}) class Foo extends AbstractBar { ... }
Foo
is a specialization of the AbstractBar
superclass that provides the Bar
service.
@Provides class Foo extends AbstractBar implements Bar{ ... }
An alternate way to express Foo
is a specialization of the AbstractBar
superclass that provides the Bar
service.
@Provides({Foo.class,Bar.class}} class Foo extends AbstractBar implements Bar{ ... }
Foo
provides the Bar
service and also provides itself as a service.
Provides
is annotated with the RequestScoped
scoping, meaning that a single instance of a type annotated with Provides
will be created per scope. RequestScoped
types do not need to be thread-safe, as they will only be referenced in a single thread.
If necessary a type can indicate that only a single instance should be created across all scopes by annotating the type with ApplicationScoped
. Any such type must be thread-safe as the instance may be referenced across multiple threads. ApplicationScoped
types cannot depend on any RequestScoped
types.
@Provides({GlobalService.class}} @ApplicationScoped class Singleton implements GlobalService{ ... }
public abstract Class<?>[] value