org.azyva.dragom.util

Class ServiceLocator

java.lang.Object

org.azyva.dragom.util.ServiceLocator

public class ServiceLocator
extends Object

Implements a simple and generic service locator.

This class allows a separation of concern between Dragom and clients regarding the use of some service-like interfaces whose implementation should be selectable at runtime.

An example of such a service-like interface is JenkinsClient.

One motivation is to allow a testing client to inject test doubles for such service-like interfaces.

Although a dependency injection framework is not used to avoid imposing external dependencies on clients, such a framework can be used by clients if desired.

This class implements the following algorithm to provide service implementations to callers:

• Services factories can be registered using setServiceFactory(java.lang.Class<ServiceInterface>, org.azyva.dragom.util.ServiceLocator.ServiceFactory<ServiceInterface>). This method could be called by a dependency injection framework such as Spring. If a service factory is registered for a service interface, it is used to create instances of the service interface;
• If a requested service does not have a registered factory, a system property "org.azyva.dragom.DefaultServiceFactory.<service interface name>" is used to obtain the name of a service factory class which must have a static "getService" method that returns an instance of the service interface;
• If a system property for the service factory class is not defined, a system property "org.azyva.dragom.DefaultServiceImpl.<service interface name>" is used to obtain the name of an implementation class which must have a no-argument constructor;
• If a system property for the service implementation class is not defined, a default service factory class "<service interface package>.impl.Default<service interface simple name>Factory" is used;
• If a default factory class is not available, a default implementation class "<service interface package>.impl.Default<service interface simple name>Impl" is used.

Author:

David Raymond

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	ServiceLocator.ServiceFactory<ServiceInterface> Interface which must be implemented by registered service factories.

Method Summary

Modifier and Type	Method and Description
static <ServiceInterface> ServiceInterface	getService(Class<ServiceInterface> classServiceInterface)
static <ServiceInterface> void	setServiceFactory(Class<ServiceInterface> classServiceInterface, ServiceLocator.ServiceFactory<ServiceInterface> serviceFactory)

Methods inherited from class java.lang.Object

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

Method Detail

setServiceFactory

public static <ServiceInterface> void setServiceFactory(Class<ServiceInterface> classServiceInterface,
                                                        ServiceLocator.ServiceFactory<ServiceInterface> serviceFactory)

getService

public static <ServiceInterface> ServiceInterface getService(Class<ServiceInterface> classServiceInterface)