Package org.springframework.scheduling.annotation

Annotation Interface Async

@Target({TYPE,METHOD}) @Retention(RUNTIME) @Documented @Reflective public @interface Async
Annotation that marks a method as a candidate for asynchronous execution.

Can also be used at the type level, in which case all the type's methods are considered as asynchronous. Note, however, that @Async is not supported on methods declared within a @Configuration class.

In terms of target method signatures, any parameter types are supported. However, the return type is constrained to either void or Future. In the latter case, you may declare the more specific CompletableFuture type which allows for richer interaction with the asynchronous task and for immediate composition with further processing steps.

A Future handle returned from the proxy will be an actual asynchronous (Completable)Future that can be used to track the result of the asynchronous method execution. However, since the target method needs to implement the same signature, it will have to return a temporary Future handle that just passes a value after computation in the execution thread: typically through CompletableFuture.completedFuture(Object). The provided value will be exposed to the caller through the actual asynchronous Future handle at runtime.

Since:
3.0
Author:
Juergen Hoeller, Chris Beams
See Also:

  • Optional Element Summary

    Optional Elements
    Modifier and Type
    Optional Element
    Description
    String
    value
    A qualifier value for the specified asynchronous operation(s).

  • Element Details

    • value

      String value
      A qualifier value for the specified asynchronous operation(s).

      May be used to determine the target executor to be used when executing the asynchronous operation(s), matching the qualifier value (or the bean name) of a specific Executor or TaskExecutor bean definition.

      When specified in a class-level @Async annotation, indicates that the given executor should be used for all methods within the class. Method-level use of Async#value always overrides any qualifier value configured at the class level.

      The qualifier value will be resolved dynamically if supplied as a SpEL expression (for example, "#{environment['myExecutor']}") or a property placeholder (for example, "${my.app.myExecutor}").

      Since:
      3.1.2
      Default:
      ""