Package ej.service.loader

Class SimpleServiceLoader

java.lang.Object

ej.service.loader.SimpleServiceLoader

All Implemented Interfaces:

ServiceLoader

Direct Known Subclasses:

CompositeServiceLoader, DependencyInjectionServiceLoader, SimpleServiceRegistry

public abstract class SimpleServiceLoader
extends Object
implements ServiceLoader

Service loader that creates service instance based on default service implementation class.

Field Summary

Fields

Modifier and Type	Field	Description
protected PackedMap<Class<?>,Object>	services	The cache of instantiated services.

Constructor Summary

Constructors

Constructor	Description
SimpleServiceLoader()	Instantiates a new default service loader.

Method Summary

Modifier and Type	Method	Description
protected <T> void	checkServicePermission(Class<T> service, String action)	Checks that an action on a service is permitted.
protected <T> T	createAlternativeImplementation(Class<T> service)	Creates an implementation for the given service and save it in the cache.
<T> T	getService(Class<T> service)	Gets the instance of the given service.
protected <T> void	putService(Class<T> service, T instance)	Put a service in the services map in a synchronized context.

Methods inherited from class java.lang.Object

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

Field Detail

services

protected final PackedMap<Class<?>,Object> services

The cache of instantiated services.

Be careful to use it in a synchronized context.

See Also:

putService(Class, Object)

Constructor Detail

SimpleServiceLoader

public SimpleServiceLoader()

Instantiates a new default service loader.

Method Detail

getService

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

Description copied from interface: ServiceLoader

Gets the instance of the given service.

If there is already an instance in cache, it is returned otherwise a new one is created.

May return null if the service is not defined.

Specified by:

getService in interface ServiceLoader

Type Parameters:

T - the service type.

Parameters:

service - the service.

Returns:

the instance of the given service.

checkServicePermission

protected <T> void checkServicePermission(Class<T> service,
                                          String action)

Checks that an action on a service is permitted.

Type Parameters:

T - the service type.

Parameters:

service - the service.

action - the action.

createAlternativeImplementation

@Nullable
protected <T> T createAlternativeImplementation(Class<T> service)
                                         throws ServiceLoadingException

Creates an implementation for the given service and save it in the cache.

Type Parameters:

T - the service type.

Parameters:

service - the service.

Returns:

a new instance of the given service or null.

Throws:

ServiceLoadingException - if an error occurs while instantiating the service instance.

putService

protected <T> void putService(Class<T> service,
                              T instance)

Put a service in the services map in a synchronized context.

Type Parameters:

T - the service type.

Parameters:

service - the service.

instance - the service instance.