Spring Annotation Programming Model

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Introduction

@AliasFor

Spring Framework 4.2 introduces first-class support for declaring and looking up aliases for annotation attributes. The new @AliasFor annotation can be used to declare a pair of aliased attributes within a single annotation or to declare an alias from one attribute in a custom composed annotation to an attribute in a meta-annotation.

For example, @ContextConfiguration from the spring-test module is now declared as follows:

public @interface ContextConfiguration {

    @AliasFor("locations")
    String[] value() default {};
    
    @AliasFor("value")
    String[] locations() default {};
    
    // ...
}

Similarly, composed annotations that override attributes from meta-annotations can now use @AliasFor for fine-grained control over exactly which attributes are overridden within an annotation hierarchy. In fact, it is now possible to declare an alias for the value attribute of a meta-annotation.

For example, one can now develop a composed annotation with a custom attribute override as follows.

@ContextConfiguration
public @interface MyTestConfig {

    @AliasFor(annotation = ContextConfiguration.class, attribute = "value")
    String[] xmlFiles();

    // ...
}

Appendix

Annotations using @AliasFor

• org.springframework.cache.annotation.Cacheable
• org.springframework.cache.annotation.CacheEvict
• org.springframework.cache.annotation.CachePut
• org.springframework.context.annotation.ComponentScan.Filter
• org.springframework.context.annotation.ComponentScan
• org.springframework.context.annotation.ImportResource
• org.springframework.context.annotation.Scope
• org.springframework.context.event.EventListener
• org.springframework.jmx.export.annotation.ManagedResource
• org.springframework.messaging.handler.annotation.Header
• org.springframework.messaging.handler.annotation.Payload
• org.springframework.messaging.simp.annotation.SendToUser
• org.springframework.test.context.ActiveProfiles
• org.springframework.test.context.ContextConfiguration
• org.springframework.test.context.jdbc.Sql
• org.springframework.test.context.TestExecutionListeners
• org.springframework.test.context.TestPropertySource
• org.springframework.transaction.annotation.Transactional
• org.springframework.transaction.event.TransactionalEventListener
• org.springframework.web.bind.annotation.ControllerAdvice
• org.springframework.web.bind.annotation.CookieValue
• org.springframework.web.bind.annotation.CrossOrigin
• org.springframework.web.bind.annotation.MatrixVariable
• org.springframework.web.bind.annotation.RequestHeader
• org.springframework.web.bind.annotation.RequestMapping
• org.springframework.web.bind.annotation.RequestParam
• org.springframework.web.bind.annotation.RequestPart
• org.springframework.web.bind.annotation.ResponseStatus
• org.springframework.web.bind.annotation.SessionAttributes
• org.springframework.web.portlet.bind.annotation.ActionMapping
• org.springframework.web.portlet.bind.annotation.RenderMapping