Package dev.webfx.platform.service

Class SingleServiceProvider

java.lang.Object

dev.webfx.platform.service.SingleServiceProvider

public final class SingleServiceProvider
extends Object

Simple utility class to get a provider that is meant to be unique. Its main benefit is that it keeps that provider in memory, so it will always return the same provider instance, without instantiating it again on subsequent calls. This would not be the case with the standard ServiceLoader, which creates a new provider instance on each call. So this utility class can be useful for pieces of code that need to refer to a provider several times, with the guarantee to have the same unique instance each time. By using this utility class, you spare the declaration of a field for storing your provider, and it can therefore be used even in interface default methods. Typical usage: private static MyProvider getMyProvider() { return SingleServiceProvider.getProvider(MyProvider.class, () -> ServiceLoader.load(MyProvider.class)); } Note: the reason why ServiceLoader.load() is written in the caller code and not in this utility class is to be compliant with the Java Platform Module System. The caller module has to declare in module-info.java that it's using this service, and only the caller code can ask the ServiceLoader to load this service, this utility class can't.

Author:

Bruno Salmon

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	SingleServiceProvider.NotFoundPolicy

Constructor Summary

Constructors

Constructor	Description
SingleServiceProvider()

Method Summary

Modifier and Type	Method	Description
static <S> S	getProvider(Class<S> serviceClass)
static <S> S	getProvider(Class<S> serviceClass, Supplier<ServiceLoader<S>> serviceLoaderSupplier)
static <S> S	getProvider(Class<S> serviceClass, Supplier<ServiceLoader<S>> serviceLoaderSupplier, SingleServiceProvider.NotFoundPolicy notFoundPolicy)
static <S> void	registerServiceInterceptor(Class<S> serviceClass, Function<S,S> interceptor)
static <S> void	registerServiceProvider(Class<S> serviceClass, S serviceInstance)
static <S> void	registerServiceSupplier(Class<S> serviceClass, Supplier<ServiceLoader<S>> serviceLoaderSupplier)
static <S> void	registerServiceSupplier(Class<S> serviceClass, Supplier<ServiceLoader<S>> serviceLoaderSupplier, SingleServiceProvider.NotFoundPolicy notFoundPolicy)

Methods inherited from class java.lang.Object

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

Constructor Details

SingleServiceProvider

public SingleServiceProvider()

Method Details

registerServiceSupplier

public static <S> void registerServiceSupplier(Class<S> serviceClass,
 Supplier<ServiceLoader<S>> serviceLoaderSupplier)

registerServiceSupplier

public static <S> void registerServiceSupplier(Class<S> serviceClass,
 Supplier<ServiceLoader<S>> serviceLoaderSupplier,
 SingleServiceProvider.NotFoundPolicy notFoundPolicy)

registerServiceProvider

public static <S> void registerServiceProvider(Class<S> serviceClass,
 S serviceInstance)

registerServiceInterceptor

public static <S> void registerServiceInterceptor(Class<S> serviceClass,
 Function<S,S> interceptor)

getProvider

public static <S> S getProvider(Class<S> serviceClass)

getProvider

public static <S> S getProvider(Class<S> serviceClass,
 Supplier<ServiceLoader<S>> serviceLoaderSupplier)

getProvider

public static <S> S getProvider(Class<S> serviceClass,
 Supplier<ServiceLoader<S>> serviceLoaderSupplier,
 SingleServiceProvider.NotFoundPolicy notFoundPolicy)