How to interrupt underlying execution of CompletableFuture

Question

I know that CompletableFuture design does not control its execution with interruptions, but I suppose some of you might have this problem. CompletableFutu

Answer 1

What about?

/** @return {@link CompletableFuture} which when cancelled will interrupt the supplier
 */
public static  CompletableFuture supplyAsyncInterruptibly(Supplier supplier, Executor executor) {
    return produceInterruptibleCompletableFuture((s) -> CompletableFuture.supplyAsync(s, executor), supplier);
}

// in case we want to do the same for similar methods later
private static  CompletableFuture produceInterruptibleCompletableFuture(
        Function,CompletableFuture> completableFutureAsyncSupplier, Supplier action) {
    FutureTask task = new FutureTask<>(action::get);
    return addCancellationAction(completableFutureAsyncSupplier.apply(asSupplier(task)), () ->
            task.cancel(true));
}

/** Ensures the specified action is executed if the given {@link CompletableFuture} is cancelled.
 */
public static  CompletableFuture addCancellationAction(CompletableFuture completableFuture,
                                                             @NonNull Runnable onCancellationAction) {
    completableFuture.whenComplete((result, throwable) -> {
        if (completableFuture.isCancelled()) {
            onCancellationAction.run();
        }
    });
    return completableFuture;  // return original CompletableFuture
}

/** @return {@link Supplier} wrapper for the given {@link RunnableFuture} which calls {@link RunnableFuture#run()}
 *          followed by {@link RunnableFuture#get()}.
 */
public static  Supplier asSupplier(RunnableFuture futureTask) throws CompletionException {
    return () -> {
        try {
            futureTask.run();
            try {
                return futureTask.get();
            } catch (ExecutionException e) {  // unwrap ExecutionExceptions
                final Throwable cause = e.getCause();
                throw (cause != null) ? cause : e;
            }
        } catch (CompletionException e) {
            throw e;
        } catch (Throwable t) {
            throw new CompletionException(t);
        }
    };
}