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Document @Bean nullable parameters optional bean injection

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Issue: SPR-16053
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sdeleuze
2018-01-23 18:02:25 +01:00
parent 97894a1c22
commit 1af052433c
1 changed files with 9 additions and 3 deletions
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src/docs/asciidoc/languages/kotlin.adoc
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@@ -149,11 +149,17 @@ define the `required` attribute. That means `@RequestParam name: String?` will
as not required and conversely `@RequestParam name: String` as being required. as not required and conversely `@RequestParam name: String` as being required.
This feature is also supported on the Spring Messaging `@Header` annotation. This feature is also supported on the Spring Messaging `@Header` annotation.
In a similar fashion, Spring bean injection with `@Autowired` or `@Inject` uses this information In a similar fashion, Spring bean injection with `@Autowired`, `@Bean` or `@Inject` uses
to determine if a bean is required or not. `@Autowired lateinit var foo: Foo` implies that a bean this information to determine if a bean is required or not.
of type `Foo` must be registered in the application context while `@Autowired lateinit var foo: Foo?`
For example, `@Autowired lateinit var foo: Foo` implies that a bean
of type `Foo` must be registered in the application context, while `@Autowired lateinit var foo: Foo?`
won’t raise an error if such bean does not exist. won’t raise an error if such bean does not exist.
Following the same principle, `@Bean fun baz(foo: Foo, bar: Bar?) = Baz(foo, bar)` implies
that a bean of type `Foo` must be registered in the application context while a bean of
type `Bar` may or may not exist. The same behavior applies to autowired constructor parameters.
[NOTE] [NOTE]
==== ====
If you are using bean validation on classes with If you are using bean validation on classes with