Fibers

gistfile1.java

/**
 * Utility class for working with fibers
 */
public final class Fibers {
    private Fibers() {
    }

    /**
     * Defines work to run inside a fiber process.
     */
    public interface Work<T> {
        T apply() throws ExecutionException, InterruptedException, SuspendExecution;
    }

    /**
     * Defines work to run inside a fiber process.
     */
    public interface VoidWork {
        void apply() throws ExecutionException, InterruptedException, SuspendExecution;
    }

    public static <T> Fiber<T> of(T t) {
        return fiber(null, () -> t);
    }

    /**
     * Creates a new fiber with the given name.  The returned fiber will be started.
     */
    public static <T> Fiber<T> fiber(final String name, final Work<T> work) {
        return new Fiber<T>(name) {
            @Override
            protected T run() throws SuspendExecution, InterruptedException {
                try {
                    return work.apply();
                } catch (ExecutionException e) {
                    throw Exceptions.rethrow(e);
                }
            }
        }.start();
    }

    /**
     * Creates a new fiber.  The returned fiber will be started.
     */
    public static <T> Fiber<T> fiber(final Work<T> work) {
        return fiber(null, work);
    }

    /**
     * Creates a new fiber with the given name.  The returned fiber will be started.
     */
    public static Fiber<Void> fiber(final String name, final VoidWork work) {
        return fiber(name, () -> {
            work.apply();
            return null;
        });
    }

    /**
     * Creates a new fiber.  The returned fiber will be started.
     */
    public static Fiber<Void> fiber(final VoidWork work) {
        return fiber(null, work);
    }

    /**
     * Sequences the list of fibers into a fiber of list.  The order of the returned list matches that of the input.
     */
    public static <T> Fiber<List<T>> sequence(final List<Fiber<T>> list) {
        return fiber("sequence", () -> {
            final List<T> stopwatches = new ArrayList<>(list.size());

            for (final Fiber<T> f : list) {
                try {
                    stopwatches.add(f.get());
                } catch (ExecutionException e) {
                    throw new RuntimeException(e);
                }
            }

            return stopwatches;
        });
    }

    public static Work<Stopwatch> time(VoidWork work) {
        return () -> {
            final Stopwatch stopwatch = Stopwatch.createStarted();
            work.apply();
            return stopwatch.stop();
        };
    }
}