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| import io.vertx.core.Future; | |
| import io.vertx.core.Promise; | |
| import java.util.concurrent.CompletableFuture; | |
| import java.util.concurrent.locks.Condition; | |
| import java.util.concurrent.locks.ReentrantLock; | |
| import java.util.function.Function; | |
| public class VertxLoomNew { | |
| interface Await { | |
| <A> A await(Future<A> future); | |
| } | |
| static class Coroutine implements Await { | |
| private final ReentrantLock lock = new ReentrantLock(); | |
| private final Condition cond = lock.newCondition(); | |
| @Override | |
| public <A> A await(Future<A> future) { | |
| lock.lock(); | |
| try { | |
| future.onComplete(ar -> { | |
| lock.lock(); | |
| try { | |
| cond.signal(); | |
| } finally { | |
| lock.unlock(); | |
| } | |
| }); | |
| cond.await(); | |
| if (future.succeeded()) { | |
| return future.result(); | |
| } else { | |
| throw new RuntimeException(future.cause()); | |
| } | |
| } catch (InterruptedException e) { | |
| e.printStackTrace(); | |
| throw new RuntimeException(e); | |
| } finally { | |
| lock.unlock(); | |
| } | |
| } | |
| } | |
| public static <A> Future<A> async(Function<Await, A> f) { | |
| Promise<A> promise = Promise.promise(); | |
| Thread.ofVirtual().start(() -> { | |
| try { | |
| promise.complete(f.apply(new Coroutine())); | |
| } catch (Exception e) { | |
| e.printStackTrace(); | |
| promise.fail(e); | |
| } | |
| }); | |
| return promise.future(); | |
| } | |
| public static void main(String[] args) { | |
| Future<String> res = async(await -> { | |
| Integer a = await.await(a()); | |
| System.out.println("done a"); | |
| Integer b = await.await(b()); | |
| System.out.println("done b"); | |
| Integer a1 = await.await(a()); | |
| System.out.println("done a1"); | |
| Integer c = await.await(async(await1 -> await1.await(a()))); | |
| return "The sum is: " + (a + b + a1 + c); | |
| }); | |
| res.onSuccess(System.out::println); | |
| // stop main method from exiting early.. | |
| res.toCompletionStage().toCompletableFuture().join(); | |
| } | |
| private static Future<Integer> a() { | |
| return Future.fromCompletionStage(CompletableFuture.supplyAsync(() -> { | |
| try { | |
| Thread.sleep(1000); | |
| return 1; | |
| } catch (Exception e) { | |
| throw new RuntimeException(e); | |
| } | |
| })); | |
| } | |
| private static Future<Integer> b() { | |
| return Future.fromCompletionStage(CompletableFuture.supplyAsync(() -> 2)); | |
| } | |
| private static Future<Integer> c() { | |
| return Future.fromCompletionStage(CompletableFuture.supplyAsync(() -> { | |
| throw new RuntimeException("hello world exception"); | |
| })); | |
| } | |
| } |
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