javascalautils.concurrent

Interface Promise<T>

Type Parameters:

T - The type this Promise will produce as result

public interface Promise<T>

A Promise that can be completed once with a value or failed once with an exception.
Together with a Future this allows a safe publication of asynchronously calculated results into another thread.

Since:

1.2

Author:

Peter Nerg

Method Summary

Modifier and Type	Method and Description
static <T> Promise<T>	apply() Creates an instance of Promise.
void	failure(Throwable throwable) Completes the Promise with an exception.
Future<T>	future() Get a Future that will hold the value once this Promise is completed.
boolean	isCompleted() Check if the Promise have been completed, with a value or an exception.
void	success(T object) Completes the Promise with a value.

Method Detail

apply

static <T> Promise<T> apply()

Creates an instance of Promise.
E.g. Promise<String> p = Promise.apply();

Type Parameters:

T - The type the Promise is expected to deliver

Returns:

The Promise instance

future

Future<T> future()

Get a Future that will hold the value once this Promise is completed.
Each Promise is connected to a single Future, invoking this method multiple times will always return the same Future instance.

Returns:

A Future that will hold the value once this Promise is completed.

isCompleted

boolean isCompleted()

Check if the Promise have been completed, with a value or an exception.

Returns:

true if the Promise has been completed. false otherwise.

success

void success(T object)

Completes the Promise with a value.

Parameters:

object - The value to complete with.

Throws:

IllegalStateException - Thrown if the Promise is already completed.

failure

void failure(Throwable throwable)

Completes the Promise with an exception.

Parameters:

throwable - The Throwable to complete with.

Throws:

IllegalStateException - Thrown if the Promise is already completed.