Package org.apache.felix.dm.annotation.api

Annotation Type AdapterService

@Retention(CLASS) @Target(TYPE) public @interface AdapterService
Annotates an Adapater service component. Adapters, like AspectService, are used to "extend" existing services, and can publish different services based on the existing one. An example would be implementing a management interface for an existing service, etc ....

When you annotate an adapter class with the @AdapterService annotation, it will be applied to any service that matches the implemented interface and filter. The adapter will be registered with the specified interface and existing properties from the original service plus any extra properties you supply here. If you declare the original service as a member it will be injected.

For "add", "change", "remove" callbacks, the following method signatures are supported: 


 (Component comp, ServiceReference ref, Service service)
 (Component comp, ServiceReference ref, Object service)
 (Component comp, ServiceReference ref)
 (Component comp, Service service)
 (Component comp, Object service)
 (Component comp)
 (Component comp, Map properties, Service service)
 (ServiceReference ref, Service service)
 (ServiceReference ref, Object service)
 (ServiceReference ref)
 (Service service)
 (Service service, Map propeerties)
 (Map properties, Service, service)
 (Service service, Dictionary properties)
 (Dictionary properties, Service service)
 (Object service)

For "swap" callbacks, the following method signatures are supported: 


 (Service old, Service replace)
 (Object old, Object replace)
 (ServiceReference old, Service old, ServiceReference replace, Service replace)
 (ServiceReference old, Object old, ServiceReference replace, Object replace)
 (Component comp, Service old, Service replace)
 (Component comp, Object old, Object replace)
 (Component comp, ServiceReference old, Service old, ServiceReference replace, Service replace)
 (Component comp, ServiceReference old, Object old, ServiceReference replace, Object replace)
 (ServiceReference old, ServiceReference replace)
 (Component comp, ServiceReference old, ServiceReference replace)

Usage Examples

Here, the AdapterService is registered into the OSGI registry each time an AdapteeService is found from the registry. The AdapterImpl class adapts the AdapteeService to the AdapterService. The AdapterService will also have the following service property: p1=v1, p2=v2 : 

 
 interface AdapteeService {
     void method1();
     void method2();
 }
 
 @Component
 @Property(name="p1", value="v1")
 class Adaptee implements AdapteeService {
     ...
 } 
 
 interface AdapterService {
     void doWork();
 }
 
 @AdapterService(adapteeService = AdapteeService.class)
 @Property(name="p2", value="v2")
 class AdapterImpl implements AdapterService {
     // The service we are adapting (injected by reflection)
     volatile AdapteeService adaptee;
   
     public void doWork() {
        adaptee.method1();
        adaptee.method2();
     }
 }
Author:
Felix Project Team

  • Required Element Summary

    Required Elements
    Modifier and Type
    Required Element
    Description
    Class<?>
    adapteeService
    Sets the adaptee service interface this adapter is applying to.

  • Optional Element Summary

    Optional Elements
    Modifier and Type
    Optional Element
    Description
    String
    adapteeFilter
    Sets the filter condition to use with the adapted service interface.
    String
    added
    The callback method to be invoked when the original service is available.
    String
    changed
    The callback method to be invoked when the original service properties have changed.
    String
    factoryMethod
    Sets the static method used to create the adapter service implementation instance.
    String
    field
    Sets the field name where to inject the original service.
    boolean
    propagate
    Specifies if adaptee service properties should be propagated to the adapter service.
    Property[]
    properties
    Sets some additional properties to use with the adapter service registration.
    Class<?>[]
    provides
    Deprecated.
    you can apply Property annotation directly on the component class.
    String
    removed
    The callback method to invoke when the service is lost.
    ServiceScope
    scope
    The service scope for the service of this Component.
    String
    swap
    name of the callback method to invoke on swap.

  • Element Details

    • provides

      Class<?>[] provides
      Deprecated.
      you can apply Property annotation directly on the component class.
      Sets the adapter service interface(s). By default, the directly implemented interface(s) is (are) used.
      Returns:
      the adapter service interface(s)
      Default:
      {}

    • properties

      Property[] properties
      Sets some additional properties to use with the adapter service registration. By default, the adapter will inherit all adaptee service properties.
      Returns:
      some additional properties
      Default:
      {}

    • adapteeService

      Class<?> adapteeService
      Sets the adaptee service interface this adapter is applying to.
      Returns:
      the adaptee service interface this adapter is applying to.

    • adapteeFilter

      String adapteeFilter
      Sets the filter condition to use with the adapted service interface.
      Returns:
      the adaptee filter
      Default:
      ""

    • factoryMethod

      String factoryMethod
      Sets the static method used to create the adapter service implementation instance. By default, the default constructor of the annotated class is used.
      Returns:
      the factory method
      Default:
      ""

    • field

      String field
      Sets the field name where to inject the original service. By default, the original service is injected in any attributes of the adapter implementation that are of the same type as the adaptee interface.
      Returns:
      the field used to inject the original service
      Default:
      ""

    • added

      String added
      The callback method to be invoked when the original service is available. This attribute can't be mixed with the field attribute.
      Returns:
      the add callback
      Default:
      ""

    • changed

      String changed
      The callback method to be invoked when the original service properties have changed. When this attribute is used, then the added attribute must also be used.
      Returns:
      the changed callback
      Default:
      ""

    • swap

      String swap
      name of the callback method to invoke on swap.
      Returns:
      the swap callback
      Default:
      ""

    • removed

      String removed
      The callback method to invoke when the service is lost. When this attribute is used, then the added attribute must also be used.
      Returns:
      the remove callback
      Default:
      ""

    • propagate

      boolean propagate
      Specifies if adaptee service properties should be propagated to the adapter service. The component provided service properties take precedence over the propagated adaptee service properties, meaning that a give component service property overrides the same property present in the propagated adaptee service properties.
      Returns:
      the service propagation flag
      Default:
      true

    • scope

      ServiceScope scope
      The service scope for the service of this Component.

      If not specified, the singleton service scope is used.

      Default:
      SINGLETON