Package dev.webfx.platform.async

Interface Promise<T>

All Superinterfaces:
Handler<AsyncResult<T>>
All Known Subinterfaces:
PromiseInternal<T>
All Known Implementing Classes:
PromiseImpl
public interface Promise<T> extends Handler<AsyncResult<T>>
Represents the writable side of an action that may, or may not, have occurred yet.

The future() method returns the Future associated 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

  • Method Details

    • promise

      static <T> Promise<T> promise()
      Create a promise that hasn't completed yet
      Type Parameters:
      T - the result type
      Returns:
      the promise

    • handle

      default void handle(AsyncResult<T> asyncResult)
      Succeed or fail this promise with the AsyncResult event.
      Specified by:
      handle in interface Handler<T>
      Parameters:
      asyncResult - the async result to handle

    • 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

    • complete

      default void complete()
      Calls complete(null)
      Throws:
      IllegalStateException - when the promise is already completed

    • fail

      default void fail(Throwable cause)
      Set the failure. Any handler will be called, if there is one, and the future will be marked as completed.
      Parameters:
      cause - the failure cause
      Throws:
      IllegalStateException - when the promise is already completed

    • fail

      default void fail(String message)
      Calls fail(Throwable) with the message.
      Parameters:
      message - the failure message
      Throws:
      IllegalStateException - when the promise is already completed

    • tryComplete

      boolean tryComplete(T result)
      Like complete(Object) but returns false when the promise is already completed instead of throwing an IllegalStateException, it returns true otherwise.
      Parameters:
      result - the result
      Returns:
      false when the future is already completed

    • tryComplete

      default boolean tryComplete()
      Calls tryComplete(null).
      Returns:
      false when the future is already completed

    • tryFail

      boolean tryFail(Throwable cause)
      Like fail(Throwable) but returns false when the promise is already completed instead of throwing an IllegalStateException, it returns true otherwise.
      Parameters:
      cause - the failure cause
      Returns:
      false when the future is already completed

    • tryFail

      default boolean tryFail(String message)
      Calls fail(Throwable) with the message.
      Parameters:
      message - the failure message
      Returns:
      false when the future is already completed

    • future

      Future<T> future()
      Returns:
      the Future associated with this promise, it can be used to be aware of the promise completion