Package io.vertx.core
Interface Promise<T>
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- All Superinterfaces:
Completable<T>
- All Known Subinterfaces:
BaseBridgeEvent,BridgeEvent,BridgeEvent,ConnectionInitEvent
public interface Promise<T> extends Completable<T>
Represents the writable side of an action that may, or may not, have occurred yet.The
future()method returns theFutureassociated with a promise, the future can be used for getting notified of the promise completion and retrieve its value.A promise extends
Handler<AsyncResult<T>>so it can be used as a callback.- Author:
- Julien Viet
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Method Summary
All Methods Static Methods Instance Methods Abstract Methods Default Methods Modifier and Type Method Description default voidcomplete()Callscomplete(null)default voidcomplete(T result)Set the result.default voidcomplete(T result, Throwable failure)Complete this instance whenfailureisnull, a success is signaled otherwise a failure is signaleddefault voidfail(String message)CallsCompletable.fail(Throwable)with themessage.default voidfail(Throwable failure)Set the failure.Future<T>future()default voidhandle(AsyncResult<T> asyncResult)Succeed or fail this promise with theAsyncResultevent.static <T> Promise<T>promise()Create a promise that hasn't completed yetdefault voidsucceed()Shortcut forsucceed(null)default voidsucceed(T result)Set the result.default booleantryComplete()CallstryComplete(null).booleantryComplete(T result)Likecomplete(Object)but returnsfalsewhen the promise is already completed instead of throwing anIllegalStateException, it returnstrueotherwise.default booleantryFail(String message)Callsfail(Throwable)with themessage.booleantryFail(Throwable cause)Likefail(Throwable)but returnsfalsewhen the promise is already completed instead of throwing anIllegalStateException, it returnstrueotherwise.
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Method Detail
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promise
static <T> Promise<T> promise()
Create a promise that hasn't completed yet- Type Parameters:
T- the result type- Returns:
- the promise
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handle
default void handle(AsyncResult<T> asyncResult)
Succeed or fail this promise with theAsyncResultevent.- Parameters:
asyncResult- the async result to handle
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complete
default void complete(T result, Throwable failure)
Description copied from interface:CompletableComplete this instance- when
failureisnull, a success is signaled - otherwise a failure is signaled
- Specified by:
completein interfaceCompletable<T>- Parameters:
result- the resultfailure- the failure
- when
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complete
default void complete(T result)
Set the result. Any handler will be called, if there is one, and the promise will be marked as completed. Any handler set on the associated promise will be called.- Parameters:
result- the result- Throws:
IllegalStateException- when the promise is already completed
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complete
default void complete()
Callscomplete(null)- Throws:
IllegalStateException- when the promise is already completed
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succeed
default void succeed(T result)
Description copied from interface:CompletableSet the result. The instance will be marked as succeeded and completed.- Specified by:
succeedin interfaceCompletable<T>- Parameters:
result- the result
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succeed
default void succeed()
Description copied from interface:CompletableShortcut forsucceed(null)- Specified by:
succeedin interfaceCompletable<T>
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fail
default void fail(Throwable failure)
Description copied from interface:CompletableSet the failure. This instance will be marked as failed and completed.- Specified by:
failin interfaceCompletable<T>- Parameters:
failure- the failure
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fail
default void fail(String message)
Description copied from interface:CompletableCallsCompletable.fail(Throwable)with themessage.- Specified by:
failin interfaceCompletable<T>- Parameters:
message- the failure message
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tryComplete
boolean tryComplete(T result)
Likecomplete(Object)but returnsfalsewhen the promise is already completed instead of throwing anIllegalStateException, it returnstrueotherwise.- Parameters:
result- the result- Returns:
falsewhen the future is already completed
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tryComplete
default boolean tryComplete()
CallstryComplete(null).- Returns:
falsewhen the future is already completed
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tryFail
boolean tryFail(Throwable cause)
Likefail(Throwable)but returnsfalsewhen the promise is already completed instead of throwing anIllegalStateException, it returnstrueotherwise.- Parameters:
cause- the failure cause- Returns:
falsewhen the future is already completed
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tryFail
default boolean tryFail(String message)
Callsfail(Throwable)with themessage.- Parameters:
message- the failure message- Returns:
- false when the future is already completed
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