AspectComponent

All Superinterfaces:: Component

public interface AspectComponent
extends Component

Interface used to configure the various parameters needed when defining a Dependency Manager aspect component. Aspects allow you to define an interceptor, or chain of interceptors for a service (to add features like caching or logging, etc ...). The dependency manager intercepts the original service, and allows you to execute some code before invoking the original service ... The aspect will be applied to any service that matches the specified interface and filter and will be registered with the same interface and properties as the original service, plus any extra properties you supply here. If you declare the original service as a member it will be injected.

Usage Examples

Here is a sample showing a DatabaseCache aspect which is created each time a Database interface is registered in the registry.

 
 public class Activator extends DependencyActivatorBase {
     &Override
     public void init(BundleContext context, DependencyManager dm) throws Exception {
         AspectComponent aspectComponent = createAspectComponent()
             .setAspect(Database.class, null, 10)
             .setImplementation(DatabaseCache.class);
         dm.add(aspectComponent);
     }
 }
 
 interface Database {
     String get(String key);
 }
 
 class DatabaseCache implements Database {
     volatile Database originalDatabase; // injected
     
     String get(String key) {
         String value = cache.get(key);
         if (value == null) {
             value = this.originalDatabase.get(key);
             store(key, value);
         }
         return value;
     }
     ... 
 }

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)

Nested Class Summary
- Nested classes/interfaces inherited from interface org.apache.felix.dm.Component
  Component.ServiceScope

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method and Description
`AspectComponent`	`add(ComponentStateListener listener)` Adds a component state listener to this component.
`AspectComponent`	`add(Dependency... dependencies)` Adds dependency(ies) to this component, atomically.
`AspectComponent`	`remove(ComponentStateListener listener)` Removes a component state listener from this component.
`AspectComponent`	`remove(Dependency d)` Removes a dependency from the component.
`AspectComponent`	`setAspect(java.lang.Class<?> service, java.lang.String filter, int ranking)` Sets the service interface to apply the aspect to (required parameter)
`AspectComponent`	`setAspectCallbackInstance(java.lang.Object callbackInstance)` Sets the instance to invoke the callbacks on (optional parameter).
`AspectComponent`	`setAspectCallbacks(java.lang.String add, java.lang.String change, java.lang.String remove, java.lang.String swap)` Sets name of the callbacks method to invoke on add,change,remove, or swap callbacks (optional parameter).
`AspectComponent`	`setAspectField(java.lang.String autoConfig)` Sets the aspect implementation field name where to inject original service (optional parameter).
`AspectComponent`	`setAutoConfig(java.lang.Class<?> clazz, boolean autoConfig)` Configures auto configuration of injected classes in the component instance.
`AspectComponent`	`setAutoConfig(java.lang.Class<?> clazz, java.lang.String instanceName)` Configures auto configuration of injected classes in the component instance.
`AspectComponent`	`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.
`AspectComponent`	`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.
`AspectComponent`	`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.
`AspectComponent`	`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.
`AspectComponent`	`setDebug(java.lang.String label)` Activate debug for this component.
`AspectComponent`	`setFactory(java.lang.Object factory, java.lang.String createMethod)` Sets the factory to use to create the implementation.
`AspectComponent`	`setFactory(java.lang.String createMethod)` Sets the factory to use to create the implementation.
`AspectComponent`	`setImplementation(java.lang.Object implementation)` Sets the implementation for this component.
`AspectComponent`	`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.
`AspectComponent`	`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.
`AspectComponent`	`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.
`AspectComponent`	`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.
`AspectComponent`	`setScope(Component.ServiceScope scope)` Sets the component scope.
`AspectComponent`	`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
```
AspectComponent 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
```
AspectComponent 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
```
AspectComponent 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
```
AspectComponent 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
```
AspectComponent add(ComponentStateListener listener)
```
    Adds a component state listener to this component.
    
    Specified by:
    
    add in interface Component
    
    Parameters:
    
    listener - the state listener
  - remove
```
AspectComponent remove(ComponentStateListener listener)
```
    Removes a component state listener from this component.
    
    Specified by:
    
    remove in interface Component
    
    Parameters:
    
    listener - the state listener
  - setInterface
```
AspectComponent 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
```
AspectComponent 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
```
AspectComponent 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
```
AspectComponent 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
```
AspectComponent 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
```
AspectComponent 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
```
AspectComponent 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
```
AspectComponent 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
```
AspectComponent 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
```
AspectComponent 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
```
AspectComponent 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
```
AspectComponent 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
```
AspectComponent 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
```
AspectComponent 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 -
  - setAspect
```
AspectComponent setAspect(java.lang.Class<?> service,
                          java.lang.String filter,
                          int ranking)
```
    Sets the service interface to apply the aspect to (required parameter)
    
    Parameters:
    
    service - the service interface to apply the aspect to
    
    filter - the filter condition to use with the service aspect interface (null if no filter)
    
    ranking - the level used to organize the aspect chain ordering
    
    Returns:
    
    this aspect parameter instance
  - setAspectField
```
AspectComponent setAspectField(java.lang.String autoConfig)
```
    Sets the aspect implementation field name where to inject original service (optional parameter). If not set or null, any field matching the original service will be injected.
    
    Parameters:
    
    autoConfig - the aspect implementation field name where to inject original service
    
    Returns:
    
    this aspect parameter instance
  - setAspectCallbacks
```
AspectComponent setAspectCallbacks(java.lang.String add,
                                   java.lang.String change,
                                   java.lang.String remove,
                                   java.lang.String swap)
```
    Sets name of the callbacks method to invoke on add,change,remove, or swap callbacks (optional parameter).
    
    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
    
    swap - name of the callback method to invoke on swap
    
    Returns:
    
    this aspect parameter instance
  - setAspectCallbackInstance
```
AspectComponent setAspectCallbackInstance(java.lang.Object callbackInstance)
```
    Sets the instance to invoke the callbacks on (optional parameter). null means the callbacks will be invoked on the aspect implementation object.
    
    Parameters:
    
    callbackInstance - the instance to invoke the callbacks on
    
    Returns:
    
    this aspect parameter instance

Interface AspectComponent

Usage Examples

Nested Class Summary

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

Method Summary

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

Method Detail

setScope

setImplementation

add

remove

add

remove

setInterface

setInterface

setInterface

setInterface

setAutoConfig

setAutoConfig

setServiceProperties

setCallbacks

setCallbacks

setFactory

setFactory

setComposition

setComposition

setDebug

setAspect

setAspectField

setAspectCallbacks

setAspectCallbackInstance