Bean registration with Kotlin DSL using callable reference with autowired parameters [SPR-17312]

[spring-projects-issues]

Sébastien Deleuze opened SPR-17312 and commented

I had this feature in mind for a long time, but this seems that autowiring of Kotlin top level functions is straightforward and require no reflection, but just leveraging Kotlin type system.

inline fun <reified T : Any> BeanDefinitionDsl.bean(crossinline f: Function0<T>): Any = context.registerBean { f.invoke() }

inline fun <reified A : Any, reified T : Any> BeanDefinitionDsl.bean(crossinline f: Function1<A, T>): Any = context.registerBean { f.invoke(context.getBean()) }

inline fun <reified A : Any, reified B : Any, reified T : Any> BeanDefinitionDsl.bean(crossinline f: Function2<A, B, T>): Any = context.registerBean { f.invoke(context.getBean(), context.getBean()) }

// To be defined the number of parameter we want to support

A typical use case is autowiring of router parameters, for example:

fun routes(userHandler: UserHandler) = router {
	GET("/", userHandler::listView)
	GET("/api/user", userHandler::listApi)
	GET("/conf", userHandler::conf)
}

beans {
	bean<UserRepository>()
	bean<UserHandler>()
	bean(::routes)
}

That would be a very nice Spring Framework 5.2 feature IMO ;-)

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No further details from SPR-17312