Package com.microej.kf.util.service

Class SharedServiceRegistryKF

java.lang.Object

ej.service.loader.SimpleServiceLoader

ej.service.registry.SimpleServiceRegistry

com.microej.kf.util.service.SharedServiceRegistryKF

All Implemented Interfaces:

SharedServiceRegistry, FeatureStateListener, ServiceLoader, ServiceRegistry

public class SharedServiceRegistryKF
extends SimpleServiceRegistry
implements SharedServiceRegistry, FeatureStateListener

Implementation of the shared service registry over Kernel and Features.

This service registry is able to handle the following kind of services:

• Services owned by the kernel, available to the kernel and the features (provided that the type is part of the API)
• Services owned by a feature using shared interfaces mechanism, available to other features through Proxy instances
• Services owned by a feature using an interface owned by the kernel, only available to the kernel (kernel extensions)
• Services owned by a feature using a type owned by the feature, only available to the feature

Field Summary

Fields inherited from class ej.service.loader.SimpleServiceLoader

services

Constructor Summary

Constructors

Constructor	Description
SharedServiceRegistryKF()	Creates a shared service registry.

Method Summary

Modifier and Type	Method	Description
<T> T	getService(Class<T> serviceClass)	Gets the registered implementation for the given service.
<T> void	register(Class<T> serviceClass, T implementation)	Registers a service instance.
void	stateChanged(Feature feature, Feature.State previousState)	Called when the state of a Feature has changed.
<T> void	unregister(Class<T> serviceClass, T implementation)	Unregisters a service instance.

Methods inherited from class ej.service.loader.SimpleServiceLoader

checkServicePermission, createAlternativeImplementation, putService

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SharedServiceRegistryKF

public SharedServiceRegistryKF()

Creates a shared service registry.

Method Detail

register

public <T> void register(Class<T> serviceClass,
                         T implementation)

Description copied from interface: ServiceRegistry

Registers a service instance.

The given instance is returned each time the service is requested by ServiceLoader.getService(Class).

If the service already has a registered instance, the previous one is replaced.

Specified by:

register in interface ServiceRegistry

Overrides:

register in class SimpleServiceRegistry

Type Parameters:

T - the service type.

Parameters:

serviceClass - the implemented service.

implementation - the service instance.

unregister

public <T> void unregister(Class<T> serviceClass,
                           T implementation)

Description copied from interface: ServiceRegistry

Unregisters a service instance.

If the given instance is not the one currently registered for the given service, nothing is done.

Specified by:

unregister in interface ServiceRegistry

Overrides:

unregister in class SimpleServiceRegistry

Type Parameters:

T - the service type.

Parameters:

serviceClass - the implemented service.

implementation - the service instance.

getService

@Nullable
public <T> T getService(Class<T> serviceClass)

Gets the registered implementation for the given service. This implementation depends on who request it. if it is a feature we search the service with the following order:

• We search it in the shared services provided by the current feature.
• We search it in the shared services provided by the kernel.
• We search it in the shared services provided by the trusted features.
• We search it in the shared services provided by the non trusted features.

if it is the kernel, we search the service with the following order:

• We search it in the shared services provided by the kernel.
• We search it in the shared services provided by the trusted features.
• We search it in the shared services provided by the non trusted features.

Specified by:

getService in interface ServiceLoader

Overrides:

getService in class SimpleServiceLoader

Type Parameters:

T - the service type.

Parameters:

serviceClass - the service to found.

Returns:

an instance of the given service or null if no implementation is available.

stateChanged

public void stateChanged(@Nullable
                         Feature feature,
                         @Nullable
                         Feature.State previousState)

Description copied from interface: FeatureStateListener

Called when the state of a Feature has changed.

Specified by:

stateChanged in interface FeatureStateListener

Parameters:

feature - the Feature which state has changed

previousState - the previous state, null if Feature state is Feature.State.INSTALLED