org.apache.felix.dm.context

Interface ComponentContext

All Superinterfaces:

Component

@ProviderType
public interface ComponentContext
extends Component

This interface is the entry point to the Component implementation context. It is used by all DependencyManager Dependency implementations.

See Also:

interface

Method Summary

Modifier and Type	Method and Description
<T> T	createConfigurationType(java.lang.Class<T> type, java.util.Dictionary<?,?> config) Creates a configuration for a given type backed by a given dictionary.
boolean	getAutoConfig(java.lang.Class<?> clazz) Indicates if an object of the given class can be injected in one field of the component
java.lang.String	getAutoConfigInstance(java.lang.Class<?> clazz) Returns the component instance field that is assignable to a given class type
org.osgi.framework.Bundle	getBundle() Returns the Compoent's bundle.
org.osgi.framework.BundleContext	getBundleContext() Returns the Component's bundle context
java.util.List<DependencyContext>	getDependencies() Returns the list of dependencies that has been registered on this component
Event	getDependencyEvent(DependencyContext dc) Returns the highest ranked dependency service instance for a given dependency
java.util.Set<Event>	getDependencyEvents(DependencyContext dc) Returns all the available dependency services for a given dependency
java.util.concurrent.Executor	getExecutor() Returns the Component Executor gate that can be used to ensure proper component event serialization.
java.lang.Object[]	getInstances() Returns the component instances
Logger	getLogger() Returns the logger which can be used by the DependencyManager Dependencies implementations.
void	handleEvent(DependencyContext dc, EventType type, Event... event) Notifies the Component about a dependency event.
void	invokeCallbackMethod(java.lang.Object[] instances, java.lang.String methodName, java.lang.Class<?>[][] signatures, java.lang.Object[][] parameters) Invokes a callback method on a given set of objects.
void	invokeCallbackMethod(java.lang.Object[] instances, java.lang.String methodName, java.lang.Class<?>[][] signatures, java.lang.Object[][] parameters, boolean logIfNotFound) Invokes a callback method on a given set of objects.
boolean	isActive() Is this component already started ?
boolean	isAvailable() Is this component available (all required dependencies are available) ?
void	setThreadPool(java.util.concurrent.Executor threadPool) Sets a threadpool that the component will use when handling external events
void	start() Starts the component.
void	stop() Stops the component.

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

add, add, getComponentDeclaration, getDependencyManager, getInstance, getServiceProperties, getServiceRegistration, remove, remove, setAutoConfig, setAutoConfig, setCallbacks, setCallbacks, setComposition, setComposition, setDebug, setFactory, setFactory, setImplementation, setInterface, setInterface, setServiceProperties

Method Detail

getExecutor

java.util.concurrent.Executor getExecutor()

Returns the Component Executor gate that can be used to ensure proper component event serialization. When you schedule a task in the component executor, your task is executed safely and you do not need to managed synchronization (other external events, like service dependency events) will be queued until your task has been executed).

getLogger

Logger getLogger()

Returns the logger which can be used by the DependencyManager Dependencies implementations.

getBundleContext

org.osgi.framework.BundleContext getBundleContext()

Returns the Component's bundle context

Returns:

the Component's bundle context

getBundle

org.osgi.framework.Bundle getBundle()

Returns the Compoent's bundle.

Returns:

the Compoent's bundle.

setThreadPool

void setThreadPool(java.util.concurrent.Executor threadPool)

Sets a threadpool that the component will use when handling external events

Parameters:

threadPool - a threadpool used to handle component events and invoke the component's lifecycle callbacks

start

void start()

Starts the component. All initial dependencies previously added to the component will be started.

stop

void stop()

Stops the component.

isActive

boolean isActive()

Is this component already started ?

Returns:

true if this component has been started

isAvailable

boolean isAvailable()

Is this component available (all required dependencies are available) ?

Returns:

true if this component is available (all dependencies are available), or false

handleEvent

void handleEvent(DependencyContext dc,
                 EventType type,
                 Event... event)

Notifies the Component about a dependency event. An event is for example fired when:

• a dependency service becomes available EventType.ADDED)
• a dependenc service has changed is changed EventType.CHANGED)
• a dependency service has been lost EventType.REMOVED)
• a dependency service has been swapped by another EventType.SWAPPED)

Parameters:

dc - the dependency

type - the dependency event type

e - the dependency event

See Also:

EventType

getDependencies

java.util.List<DependencyContext> getDependencies()

Returns the list of dependencies that has been registered on this component

Returns:

the list of dependencies that has been registered on this component

invokeCallbackMethod

void invokeCallbackMethod(java.lang.Object[] instances,
                          java.lang.String methodName,
                          java.lang.Class<?>[][] signatures,
                          java.lang.Object[][] parameters)

Invokes a callback method on a given set of objects. An error is logged if the callback is not found in any of the object instances.

Parameters:

instances - the component instances

methodName - the method name

signatures - the method signatures (types)

parameters - the method parameters

invokeCallbackMethod

void invokeCallbackMethod(java.lang.Object[] instances,
                          java.lang.String methodName,
                          java.lang.Class<?>[][] signatures,
                          java.lang.Object[][] parameters,
                          boolean logIfNotFound)

Invokes a callback method on a given set of objects.

Parameters:

instances - the component instances

methodName - the method name

signatures - the method signatures (types)

parameters - the method parameters

logIfNotFound - true if a warning message should be logged in case the callback is not found in any of the object instances.

getInstances

java.lang.Object[] getInstances()

Returns the component instances

Specified by:

getInstances in interface Component

Returns:

the component instances

getAutoConfigInstance

java.lang.String getAutoConfigInstance(java.lang.Class<?> clazz)

Returns the component instance field that is assignable to a given class type

Parameters:

clazz - the type of an object that has to be injected in the component instance field

Returns:

the name of the component instance field that can be assigned to an object having the same type as the "clazz" parameter

getAutoConfig

boolean getAutoConfig(java.lang.Class<?> clazz)

Indicates if an object of the given class can be injected in one field of the component

Parameters:

clazz - the class of an object that has to be injected in one of the component fields

Returns:

true if the component can be injected with an object having the specified "clazz" type.

getDependencyEvent

Event getDependencyEvent(DependencyContext dc)

Returns the highest ranked dependency service instance for a given dependency

Parameters:

dc - the dependency

Returns:

the highest ranked dependency service instance for a given dependency

getDependencyEvents

java.util.Set<Event> getDependencyEvents(DependencyContext dc)

Returns all the available dependency services for a given dependency

Parameters:

dc - the dependency

Returns:

all the available dependency services for a given dependency

createConfigurationType

<T> T createConfigurationType(java.lang.Class<T> type,
                              java.util.Dictionary<?,?> config)

Creates a configuration for a given type backed by a given dictionary. This method can be used by any custom Dependency Manager dependency that needs to expose some configuration through a dynamic proxy interface.

Parameters:

type - the configuration class, cannot be null;

config - the configuration to wrap, cannot be null.

Returns:

an instance of the given type that wraps the given configuration.