Module io.inverno.core.annotation
Package io.inverno.core.annotation

Annotation Interface Provide

@Retention(CLASS) @Target({TYPE,TYPE_USE}) public @interface Provide

Specifies the type provided by a bean, defaulting to the actual bean type.

This allows to control how a bean is actually exposed. For instance, you might not want to expose the actual bean type which is most likely an implementation class not exported by the module and therefore not accessible to external Java modules anyway, you'd rather choose to expose a public class or an interface extended or implemented by the bean class.

This annotation can be either specified on the Bean annotated type or on one of its a super type. In the first case, the provided type is specified by the annotation value, in the second case, the provided type is the annotated direct super type, the annotation value being ignored. Defining a type incompatible with the actual bean type or Specifying the annotation multiple times will result in a compilation errors.

For example, the following bean will be exposed as SomeService outside the module. A bean can only provide one single type. 


 @Bean
 @Provide(SomeService.class)
 public class ModuleBean implements SomeService, SomeOtherService {

 }

which is equivalent to: 


 @Bean
 public class ModuleBean implements @Provide SomeService, SomeOtherService {

 }

Note that this also has an impact on bean wiring. From within the module the bean provides its actual visible type which can then be wired to any assignable socket. From outside the module, wiring is only based on the provided type. There is however one exception when the annotation is used on an overridable bean, the wired type inside and outside the module is always the provided type.

Since:
1.0
Author:
Jeremy Kuhn
See Also:

  • Optional Element Summary

    Optional Elements
    Modifier and Type
    Optional Element
    Description
    Class<?>
    value
    Specifies the type provided by the bean.

  • Element Details

    • value

      Class<?> value

      Specifies the type provided by the bean.

      This type must be compatible with the actual bean type.

      Returns:
      A type
      Default:
      java.lang.Object.class