Package org.apache.felix.dm

Interface ResourceComponent

All Superinterfaces:
Component
public interface ResourceComponent extends Component
Interface used to configure the various parameters needed when defining a Dependency Manager resource adapter component. The resource adapter will be applied to any resource that matches the specified filter condition. For each matching resource an adapter will be created based on the adapter implementation class. The adapter will be registered with the specified interface and existing properties from the original resource plus any extra properties you supply here. It will also inherit all dependencies, and if you declare the original service as a member it will be injected.

Usage Examples

Here is a sample showing a VideoPlayer adapter component which plays a video found from a bundle having a Video-Path manifest header. 
 
 public class Activator extends DependencyActivatorBase {
     &Override
     public void init(BundleContext context, DependencyManager dm) throws Exception {
          ResourceComponent resourceComponent = dm.createResourceComponent()
             .setResourceFilter("(path=/videos/*.mkv)")
             .setInterface(VideoPlayer.class, null)
             .setImplementation(VideoPlayerImpl.class);
         dm.add(resourceComponent);
     }
 }
 
 public interface VideoPlayer {
     void play();
 }
 
 public class VideoPlayerImpl implements VideoPlayer {
     volatile URL resource; // injected 
     
     void play() {
         ...
     }
 }

When you use callbacks to get injected with the resource, the "add", "change" callbacks support the following method signatures: 


 (Component, URL, Dictionary)
 (Component, URL)
 (Component) 
 (URL, Dictionary)
 (URL)
 (Object)
See Also:

  • Method Details

    • setScope

      ResourceComponent setScope(Component.ServiceScope scope)
      Sets the component scope.
      Specified by:
      setScope in interface Component
      Parameters:
      scope - the component scope (default=SINGLETON)
      Returns:
      this component

    • setImplementation

      ResourceComponent setImplementation(Object implementation)
      Sets the implementation for this component. You can actually specify an instance you have instantiated manually, or a Class that will be instantiated using its default constructor when the required dependencies are resolved, effectively giving you a lazy instantiation mechanism. There are four special methods that are called when found through reflection to give you life cycle management options:
      1. init() is invoked after the instance has been created and dependencies have been resolved, and can be used to initialize the internal state of the instance or even to add more dependencies based on runtime state
      2. start() is invoked right before the service is registered
      3. stop() is invoked right after the service is unregistered
      4. destroy() is invoked after all dependencies are removed
      In short, this allows you to initialize your instance before it is registered, perform some post-initialization and pre-destruction code as well as final cleanup. If a method is not defined, it simply is not called, so you can decide which one(s) you need. If you need even more fine-grained control, you can register as a service state listener too.
      Specified by:
      setImplementation in interface Component
      Parameters:
      implementation - the implementation
      Returns:
      this component
      See Also:

    • add

      ResourceComponent add(Dependency... dependencies)
      Adds dependency(ies) to this component, atomically. If the component is already active or if you add dependencies from the init method, then you should add all the dependencies in one single add method call (using the varargs argument), because this method may trigger component activation (like the ServiceTracker.open() method does).
      Specified by:
      add in interface Component
      Parameters:
      dependencies - the dependencies to add.
      Returns:
      this component

    • remove

      ResourceComponent remove(Dependency d)
      Removes a dependency from the component.
      Specified by:
      remove in interface Component
      Parameters:
      d - the dependency to remove
      Returns:
      this component

    • add

      ResourceComponent add(ComponentStateListener listener)
      Adds a component state listener to this component.
      Specified by:
      add in interface Component
      Parameters:
      listener - the state listener

    • remove

      ResourceComponent remove(ComponentStateListener listener)
      Removes a component state listener from this component.
      Specified by:
      remove in interface Component
      Parameters:
      listener - the state listener

    • setInterface

      ResourceComponent setInterface(String serviceName, Dictionary<?,?> properties)
      Sets the public interface under which this component should be registered in the OSGi service registry.
      Specified by:
      setInterface in interface Component
      Parameters:
      serviceName - the name of the service interface
      properties - the properties for this service
      Returns:
      this component

    • setInterface

      ResourceComponent setInterface(String[] serviceNames, Dictionary<?,?> properties)
      Sets the public interfaces under which this component should be registered in the OSGi service registry.
      Specified by:
      setInterface in interface Component
      Parameters:
      serviceNames - the names of the service interface
      properties - the properties for these services
      Returns:
      this component

    • setInterface

      ResourceComponent setInterface(Class<?> serviceName, Dictionary<?,?> properties)
      Sets the public interface under which this component should be registered in the OSGi service registry.
      Specified by:
      setInterface in interface Component
      Parameters:
      serviceName - the name of the service interface
      properties - the properties for this service
      Returns:
      this component

    • setInterface

      ResourceComponent setInterface(Class<?>[] serviceNames, Dictionary<?,?> properties)
      Sets the public interfaces under which this component should be registered in the OSGi service registry.
      Specified by:
      setInterface in interface Component
      Parameters:
      serviceNames - the names of the service interface
      properties - the properties for these services
      Returns:
      this component

    • setAutoConfig

      ResourceComponent setAutoConfig(Class<?> clazz, boolean autoConfig)
      Configures auto configuration of injected classes in the component instance. The following injections are currently performed, unless you explicitly turn them off:
      BundleContext
      the bundle context of the bundle
      ServiceRegistration
      the service registration used to register your service
      DependencyManager
      the dependency manager instance
      Component
      the component instance of the dependency manager
      Specified by:
      setAutoConfig in interface Component
      Parameters:
      clazz - the class (from the list above)
      autoConfig - false to turn off auto configuration

    • setAutoConfig

      ResourceComponent setAutoConfig(Class<?> clazz, String instanceName)
      Configures auto configuration of injected classes in the component instance.
      Specified by:
      setAutoConfig in interface Component
      Parameters:
      clazz - the class (from the list above)
      instanceName - the name of the instance to inject the class into
      See Also:

    • setServiceProperties

      ResourceComponent setServiceProperties(Dictionary<?,?> serviceProperties)
      Sets the service properties associated with the component. If the service was already registered, it will be updated.
      Specified by:
      setServiceProperties in interface Component
      Parameters:
      serviceProperties - the properties

    • setCallbacks

      ResourceComponent setCallbacks(String init, String start, String stop, String destroy)
      Sets the names of the methods used as callbacks. These methods, when found, are invoked as part of the life cycle management of the component implementation. The dependency manager will look for a method of this name with the following signatures, in this order:
      1. method(Component component)
      2. method()
      Specified by:
      setCallbacks in interface Component
      Parameters:
      init - the name of the init method
      start - the name of the start method
      stop - the name of the stop method
      destroy - the name of the destroy method
      Returns:
      the component

    • setCallbacks

      ResourceComponent setCallbacks(Object instance, String init, String start, String stop, String destroy)
      Sets the names of the methods used as callbacks. These methods, when found, are invoked on the specified instance as part of the life cycle management of the component implementation.

      See setCallbacks(String init, String start, String stop, String destroy) for more information on the signatures. Specifying an instance means you can create a manager that will be invoked whenever the life cycle of a component changes and this manager can then decide how to expose this life cycle to the actual component, offering an important indirection when developing your own component models.

      Specified by:
      setCallbacks in interface Component
      Returns:
      this component

    • setFactory

      ResourceComponent setFactory(Object factory, String createMethod)
      Sets the factory to use to create the implementation. You can specify both the factory class and method to invoke. The method should return the implementation, and can use any method to create it. Actually, this can be used together with setComposition to create a composition of instances that work together to implement a component. The factory itself can also be instantiated lazily by not specifying an instance, but a Class.
      Specified by:
      setFactory in interface Component
      Parameters:
      factory - the factory instance or class
      createMethod - the name of the create method
      Returns:
      this component

    • setFactory

      ResourceComponent setFactory(String createMethod)
      Sets the factory to use to create the implementation. You specify the method to invoke. The method should return the implementation, and can use any method to create it. Actually, this can be used together with setComposition to create a composition of instances that work together to implement a component.

      Note that currently, there is no default for the factory, so please use setFactory(factory, createMethod) instead.

      Specified by:
      setFactory in interface Component
      Parameters:
      createMethod - the name of the create method
      Returns:
      this component

    • setComposition

      ResourceComponent setComposition(Object instance, String getMethod)
      Sets the instance and method to invoke to get back all instances that are part of a composition and need dependencies injected. All of them will be searched for any of the dependencies. The method that is invoked must return an Object[].
      Specified by:
      setComposition in interface Component
      Parameters:
      instance - the instance that has the method
      getMethod - the method to invoke
      Returns:
      this component

    • setComposition

      ResourceComponent setComposition(String getMethod)
      Sets the method to invoke on the service implementation to get back all instances that are part of a composition and need dependencies injected. All of them will be searched for any of the dependencies. The method that is invoked must return an Object[].
      Specified by:
      setComposition in interface Component
      Parameters:
      getMethod - the method to invoke
      Returns:
      this component

    • setDebug

      ResourceComponent setDebug(String label)
      Activate debug for this component. Informations related to dependency processing will be displayed using osgi log service, our to standard output if no log service is currently available.
      Specified by:
      setDebug in interface Component
      Parameters:
      label -

    • setResourceFilter

      ResourceComponent setResourceFilter(String filter)
      Sets the resource filter used to match a given resource URL.
      Parameters:
      filter - the filter condition to use with the resource
      Returns:
      this ResourceComponent

    • setPropagate

      ResourceComponent setPropagate(boolean propagate)
      Sets if properties from the resource should be propagated to the resource adapter service. true by default.
      Parameters:
      propagate - true if if properties from the resource should be propagated to the resource adapter service. true by default. The provided resource adapter service properties take precedence over the propagated resource service properties.
      Returns:
      this ResourceComponent

    • setPropagate

      ResourceComponent setPropagate(Object propagateCbInstance, String propagateCbMethod)
      Sets the propagate callback to invoke in order to propagate the resource properties to the adapter service. The provided resource adapter service properties take precedence over the propagated resource service properties.
      Parameters:
      propagateCbInstance - the object to invoke the propagate callback method on
      propagateCbMethod - the method name to invoke in order to propagate the resource properties to the adapter service.
      Returns:
      this ResourceComponent

    • setBundleCallbacks

      ResourceComponent setBundleCallbacks(String add, String change)
      Sets the callbacks to invoke when injecting the resource into the adapter component.
      Parameters:
      add - the method to invoke when injected the resource into the adapter component
      change - the method to invoke when the resource properties have changed
      Returns:
      this ResourceComponent

    • setBundleCallbackInstance

      ResourceComponent setBundleCallbackInstance(Object callbackInstance)
      Sets the instance to invoke the callbacks on (null by default, meaning the callbacks have to be invoked on the resource adapter itself)
      Parameters:
      callbackInstance - the instance to invoke the callbacks on (null by default, meaning the callbacks have to be invoked on the resource adapter itself)
      Returns:
      this ResourceComponent