org.apache.felix.dm

Interface BundleComponent

All Superinterfaces:

Component

public interface BundleComponent
extends Component

Interface used to configure the various parameters needed when defining a Dependency Manager bundle adapter component. Bundle Adapters, like AdapterComponent, are used to "extend" existing bundles, and can publish an adapter services based on the existing bundle. An example would be implementing a video player which adapters a resource bundle having some specific headers.

When you create a bundle adapter component, it will be applied to any bundle that matches the specified bundle state mask as well as the specified ldap filter used to match the bundle manifest headers. The bundle adapter will be registered with the specified bundle manifest headers as service properties, plus any extra properties you suppl. If you declare a bundle field in your bundle adapter class, it will be injected it will be injected with the original bundle.

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 {
         BundleComponent bundleComponent = createBundleComponent()
             .setFilter(Bundle.ACTIVE, "(Video-Path=*)")
             .setInterface(VideoPlayer.class.getName(), null)
             .setImplementation(VideoPlayerImpl.class);
         dm.add(bundleComponent);
     }
 }
 
 public interface VideoPlayer {
     void play();
 }
 
 public class VideoPlayerImpl implements VideoPlayer {
     volatile Bundle bundle; // injected
     String path;
     
     void start() {
        path = bundle.getHeaders().get("Video-Path");
     }
     
     void play() {
         ...
     }
 }
  

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

 (Bundle)
 (Object)
 (COmponent, Bundle)
 

See Also:

DependencyManager.createBundleComponent()

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.felix.dm.Component

Component.ServiceScope

Method Summary

Modifier and Type	Method and Description
BundleComponent	add(ComponentStateListener listener) Adds a component state listener to this component.
BundleComponent	add(Dependency... dependencies) Adds dependency(ies) to this component, atomically.
BundleComponent	remove(ComponentStateListener listener) Removes a component state listener from this component.
BundleComponent	remove(Dependency d) Removes a dependency from the component.
BundleComponent	setAutoConfig(java.lang.Class<?> clazz, boolean autoConfig) Configures auto configuration of injected classes in the component instance.
BundleComponent	setAutoConfig(java.lang.Class<?> clazz, java.lang.String instanceName) Configures auto configuration of injected classes in the component instance.
BundleComponent	setBundleCallbackInstance(java.lang.Object callbackInstance) Sets the instance to invoke the callbacks on (null by default, meaning the callbacks have to be invoked on the adapter itself)
BundleComponent	setBundleCallbacks(java.lang.String add, java.lang.String change, java.lang.String remove) Sets the callbacks to invoke when injecting the bundle into the adapter component.
BundleComponent	setBundleFilter(int bundleStateMask, java.lang.String bundleFilter) Sets the bundle state mask and bundle manifest headers filter.
BundleComponent	setCallbacks(java.lang.Object instance, java.lang.String init, java.lang.String start, java.lang.String stop, java.lang.String destroy) Sets the names of the methods used as callbacks.
BundleComponent	setCallbacks(java.lang.String init, java.lang.String start, java.lang.String stop, java.lang.String destroy) Sets the names of the methods used as callbacks.
BundleComponent	setComposition(java.lang.Object instance, java.lang.String getMethod) Sets the instance and method to invoke to get back all instances that are part of a composition and need dependencies injected.
BundleComponent	setComposition(java.lang.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.
BundleComponent	setDebug(java.lang.String label) Activate debug for this component.
BundleComponent	setFactory(java.lang.Object factory, java.lang.String createMethod) Sets the factory to use to create the implementation.
BundleComponent	setFactory(java.lang.String createMethod) Sets the factory to use to create the implementation.
BundleComponent	setImplementation(java.lang.Object implementation) Sets the implementation for this component.
BundleComponent	setInterface(java.lang.Class<?>[] serviceNames, java.util.Dictionary<?,?> properties) Sets the public interfaces under which this component should be registered in the OSGi service registry.
BundleComponent	setInterface(java.lang.Class<?> serviceName, java.util.Dictionary<?,?> properties) Sets the public interface under which this component should be registered in the OSGi service registry.
BundleComponent	setInterface(java.lang.String[] serviceNames, java.util.Dictionary<?,?> properties) Sets the public interfaces under which this component should be registered in the OSGi service registry.
BundleComponent	setInterface(java.lang.String serviceName, java.util.Dictionary<?,?> properties) Sets the public interface under which this component should be registered in the OSGi service registry.
BundleComponent	setPropagate(boolean propagate) Sets if the bundle manifest headers should be propagated to the bundle component adapter service consumer (true by default).
BundleComponent	setScope(Component.ServiceScope scope) Sets the component scope.
BundleComponent	setServiceProperties(java.util.Dictionary<?,?> serviceProperties) Sets the service properties associated with the component.

Methods inherited from interface org.apache.felix.dm.Component

getComponentDeclaration, getDependencyManager, getInstance, getInstances, getServiceProperties, getServiceRegistration

Method Detail

setScope

BundleComponent 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

BundleComponent setImplementation(java.lang.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:

ComponentStateListener

add

BundleComponent 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

BundleComponent 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

BundleComponent add(ComponentStateListener listener)

Adds a component state listener to this component.

Specified by:

add in interface Component

Parameters:

listener - the state listener

remove

BundleComponent remove(ComponentStateListener listener)

Removes a component state listener from this component.

Specified by:

remove in interface Component

Parameters:

listener - the state listener

setInterface

BundleComponent setInterface(java.lang.String serviceName,
                             java.util.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

BundleComponent setInterface(java.lang.String[] serviceNames,
                             java.util.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

BundleComponent setInterface(java.lang.Class<?> serviceName,
                             java.util.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

BundleComponent setInterface(java.lang.Class<?>[] serviceNames,
                             java.util.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

BundleComponent setAutoConfig(java.lang.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

BundleComponent setAutoConfig(java.lang.Class<?> clazz,
                              java.lang.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:

setAutoConfig(Class, boolean)

setServiceProperties

BundleComponent setServiceProperties(java.util.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

BundleComponent setCallbacks(java.lang.String init,
                             java.lang.String start,
                             java.lang.String stop,
                             java.lang.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

BundleComponent setCallbacks(java.lang.Object instance,
                             java.lang.String init,
                             java.lang.String start,
                             java.lang.String stop,
                             java.lang.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

BundleComponent setFactory(java.lang.Object factory,
                           java.lang.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

BundleComponent setFactory(java.lang.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

BundleComponent setComposition(java.lang.Object instance,
                               java.lang.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

BundleComponent setComposition(java.lang.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

BundleComponent setDebug(java.lang.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 -

setBundleFilter

BundleComponent setBundleFilter(int bundleStateMask,
                                java.lang.String bundleFilter)

Sets the bundle state mask and bundle manifest headers filter.

Parameters:

bundleStateMask - the bundle state mask to apply

bundleFilter - the filter to apply to the bundle manifest

Returns:

this BundleComponent

setBundleCallbacks

BundleComponent setBundleCallbacks(java.lang.String add,
                                   java.lang.String change,
                                   java.lang.String remove)

Sets the callbacks to invoke when injecting the bundle into the adapter component.

Parameters:

add - name of the callback method to invoke on add

change - name of the callback method to invoke on change

remove - name of the callback method to invoke on remove

Returns:

this BundleComponent

setBundleCallbackInstance

BundleComponent setBundleCallbackInstance(java.lang.Object callbackInstance)

Sets the instance to invoke the callbacks on (null by default, meaning the callbacks have to be invoked on the adapter itself)

Parameters:

callbackInstance - the instance to invoke the callbacks on (null by default, meaning the callbacks have to be invoked on the adapter itself)

Returns:

this BundleComponent

setPropagate

BundleComponent setPropagate(boolean propagate)

Sets if the bundle manifest headers should be propagated to the bundle component adapter service consumer (true by default). The component service properties take precedence over the propagated bundle manifest headers.

Parameters:

propagate - true if the bundle manifest headers should be propagated to the adapter service consumers

Returns:

this BundleComponent