@Target(value={METHOD,TYPE})
@Retention(value=RUNTIME)
@Documented
public @interface Async
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 ListenableFuture
or
CompletableFuture
types which allow 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
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
through: e.g. Spring's AsyncResult
, EJB 3.1's AsyncResult
,
or CompletableFuture.completedFuture(Object)
.
AnnotationAsyncExecutionInterceptor
,
AsyncAnnotationAdvisor
Modifier and Type | Optional Element and Description |
---|---|
java.lang.String |
value
A qualifier value for the specified asynchronous operation(s).
|
public abstract java.lang.String value
May be used to determine the target executor to be used when executing this
method, matching the qualifier value (or the bean name) of a specific
Executor
or
TaskExecutor
bean definition.
When specified on 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 value set at the class level.