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
Members list
Value members
Abstract methods
Future containing the value of this promise.
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
trueif the promise is already completed,falseotherwise- Source
- Promise.scala
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, ortrueotherwise.- Source
- Promise.scala
Concrete methods
Completes the promise with either an exception or a value.
Completes the promise with either an exception or a value.
Value parameters
- 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.
Attributes
- Source
- Promise.scala
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
Completes the promise with an exception.
Completes the promise with an exception.
Value parameters
- 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
ExecutionExceptionwhich will fail the promise. If the promise has already been fulfilled, failed or has timed out, calling this method will throw an IllegalStateException.
Attributes
- Source
- Promise.scala
Completes the promise with a value.
Completes the promise with a value.
Value parameters
- 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.
Attributes
- 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, ortrueotherwise.- Source
- Promise.scala
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, ortrueotherwise.- Source
- Promise.scala
Deprecated methods
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
[Since version 2.13.0]Since this method is semantically equivalent to `completeWith`, use that instead.- Source
- Promise.scala