Packages

final class Promise[E, A] extends AnyVal

A promise represents an asynchronous variable that can be set exactly once, with the ability for an arbitrary number of fibers to suspend (by calling get) and automatically resume when the variable is set.

Promises can be used for building primitive actions whose completions require the coordinated action of multiple fibers, and for building higher-level concurrent or asynchronous structures.

for {
  promise <- Promise.make[Nothing, Int]
  _       <- promise.complete(42).delay(1.second).fork
  value   <- promise.get // Resumes when forked fiber completes promise
} yield value
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Value Members

  1. final def !=(arg0: Any): Boolean
    Definition Classes
    Any
  2. final def ##(): Int
    Definition Classes
    Any
  3. final def ==(arg0: Any): Boolean
    Definition Classes
    Any
  4. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  5. final def complete(a: A): IO[Nothing, Boolean]

    Completes the promise with the specified value.

  6. final def done(r: ExitResult[E, A]): IO[Nothing, Boolean]

    Completes the promise with the specified result.

    Completes the promise with the specified result. If the specified promise has already been completed, the method will produce false.

  7. final def error(e: E): IO[Nothing, Boolean]

    Fails the promise with the specified error, which will be propagated to all fibers waiting on the value of the promise.

  8. final def get: IO[E, A]

    Retrieves the value of the promise, suspending the fiber running the action until the result is available.

  9. def getClass(): Class[_ <: AnyVal]
    Definition Classes
    AnyVal → Any
  10. final def interrupt: IO[Nothing, Boolean]

    Interrupts the promise with no specified reason.

    Interrupts the promise with no specified reason. This will interrupt all fibers waiting on the value of the promise.

  11. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  12. final def poll: IO[Unit, ExitResult[E, A]]

    Retrieves immediately the ExitResult of this promise if done and fails immediately with Unit otherwise

  13. def toString(): String
    Definition Classes
    Any

Inherited from AnyVal

Inherited from Any

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