8567402969
This commit extract spring-related links and recurring external links into asciidoctor attributes to be used by the Antora toolchain. It notably homogenizes links to: - IETF RFCs - Java Community Process JSRs - the Java API Documentation (on the Java 17 version) - Kotlin documentations (on the Kotlinlang.org version) - the Spring Boot reference guide (on the `html` version) This commit also reworks most link attributes to follow a Project-Category-Misc syntax. For example, `spring-boot-docs` rather than `docs-spring-boot`. Finally, it makes an effort to clean up remainders from the previous documentation toolchain, namely the `docs/asciidoc` folder and `modules/ROOT/pages/attributes.adoc` file. Closes gh-26864 Closes gh-31619
30 lines
1.4 KiB
Plaintext
30 lines
1.4 KiB
Plaintext
[[kotlin-annotations]]
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= Annotations
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The Spring Framework also takes advantage of {kotlin-docs}/null-safety.html[Kotlin null-safety]
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to determine if an HTTP parameter is required without having to explicitly
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define the `required` attribute. That means `@RequestParam name: String?` is treated
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as not required and, conversely, `@RequestParam name: String` is treated as being required.
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This feature is also supported on the Spring Messaging `@Header` annotation.
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In a similar fashion, Spring bean injection with `@Autowired`, `@Bean`, or `@Inject` uses
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this information to determine if a bean is required or not.
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For example, `@Autowired lateinit var thing: Thing` implies that a bean
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of type `Thing` must be registered in the application context, while `@Autowired lateinit var thing: Thing?`
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does not raise an error if such a bean does not exist.
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Following the same principle, `@Bean fun play(toy: Toy, car: Car?) = Baz(toy, Car)` implies
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that a bean of type `Toy` must be registered in the application context, while a bean of
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type `Car` may or may not exist. The same behavior applies to autowired constructor parameters.
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NOTE: If you use bean validation on classes with properties or a primary constructor
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parameters, you may need to use
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{kotlin-docs}/annotations.html#annotation-use-site-targets[annotation use-site targets],
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such as `@field:NotNull` or `@get:Size(min=5, max=15)`, as described in
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{stackoverflow-site}/a/35853200/1092077[this Stack Overflow response].
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