Promise

scala.concurrent.Promise
See thePromise companion object
trait Promise[T]

Promise is an object which can be completed with a value or failed with an exception.

A promise should always eventually be completed, whether for success or failure, in order to avoid unintended resource retention for any associated Futures' callbacks or transformations.

Attributes

Companion:
object
Source:
Promise.scala
Graph
Supertypes
class Object
trait Matchable
class Any

Members list

Concise view

Value members

Abstract methods

def future: Future[T]

Future containing the value of this promise.

Future containing the value of this promise.

Attributes

Source:
Promise.scala

Returns whether the promise has already been completed with a value or an exception.

Returns whether the promise has already been completed with a value or an exception.

Note: Using this method may result in non-deterministic concurrent programs.

Attributes

Returns:

true if the promise is already completed, false otherwise

Source:
Promise.scala
def tryComplete(result: Try[T]): Boolean

Tries to complete the promise with either a value or the exception.

Tries to complete the promise with either a value or the exception.

Note: Using this method may result in non-deterministic concurrent programs.

Attributes

Returns:

If the promise has already been completed returns false, or true otherwise.

Source:
Promise.scala

Concrete methods

def complete(result: Try[T]): Promise.this.type

Completes the promise with either an exception or a value.

Completes the promise with either an exception or a value.

Attributes

result

Either the value or the exception to complete the promise with. If the promise has already been fulfilled, failed or has timed out, calling this method will throw an IllegalStateException.

Source:
Promise.scala
def completeWith(other: Future[T]): Promise.this.type

Completes this promise with the specified future, once that future is completed.

Completes this promise with the specified future, once that future is completed.

Attributes

Returns:

This promise

Source:
Promise.scala
def failure(cause: Throwable): Promise.this.type

Completes the promise with an exception.

Completes the promise with an exception.

Attributes

cause

The throwable to complete the promise with. If the throwable used to fail this promise is an error, a control exception or an interrupted exception, it will be wrapped as a cause within an ExecutionException which will fail the promise. If the promise has already been fulfilled, failed or has timed out, calling this method will throw an IllegalStateException.

Source:
Promise.scala
def success(value: T): Promise.this.type

Completes the promise with a value.

Completes the promise with a value.

Attributes

value

The value to complete the promise with. If the promise has already been fulfilled, failed or has timed out, calling this method will throw an IllegalStateException.

Source:
Promise.scala

Tries to complete the promise with an exception.

Tries to complete the promise with an exception.

Note: Using this method may result in non-deterministic concurrent programs.

Attributes

Returns:

If the promise has already been completed returns false, or true otherwise.

Source:
Promise.scala
def trySuccess(value: T): Boolean

Tries to complete the promise with a value.

Tries to complete the promise with a value.

Note: Using this method may result in non-deterministic concurrent programs.

Attributes

Returns:

If the promise has already been completed returns false, or true otherwise.

Source:
Promise.scala

Deprecated methods

final def tryCompleteWith(other: Future[T]): Promise.this.type

Attempts to complete this promise with the specified future, once that future is completed.

Attempts to complete this promise with the specified future, once that future is completed.

Attributes

Returns:

This promise

Deprecated
true
Source:
Promise.scala