better promise joining and combining

futur-api/src/main/java/dev/tommyjs/futur/executor/PromiseExecutor.java

@@ -10,4 +10,12 @@ public interface PromiseExecutor {
 
     void runAsync(@NotNull Runnable task, long delay, @NotNull TimeUnit unit);
 
+    default void runSync(@NotNull Runnable task) {
+        runSync(task, 0L, TimeUnit.MILLISECONDS);
+    }
+
+    default void runAsync(@NotNull Runnable task) {
+        runAsync(task, 0L, TimeUnit.MILLISECONDS);
+    }
+
 }

futur-api/src/main/java/dev/tommyjs/futur/promise/AbstractPromise.java

@@ -13,7 +13,6 @@ import java.util.Collection;
 import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
-import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicReference;
 
 public abstract class AbstractPromise<T> implements Promise<T> {
@@ -30,28 +29,42 @@ public abstract class AbstractPromise<T> implements Promise<T> {
 
     protected abstract Logger getLogger();
 
+    @Deprecated
     @Override
-    public T join(long interval, long timeout) throws TimeoutException {
+    public T join(long interval, long timeoutMillis) throws TimeoutException {
-        long start = System.currentTimeMillis();
+        return join(timeoutMillis);
-        while (!isCompleted()) {
+    }
-            if (System.currentTimeMillis() > start + timeout)
-                throw new TimeoutException("Promise timed out after " + timeout + "ms");
 
+    @Override
+    public T join(long timeoutMillis) throws TimeoutException {
+        PromiseCompletion<T> completion = this.completion.get();
+        if (completion != null) return joinCompletion(completion);
+
+        long start = System.currentTimeMillis();
+        long remainingTimeout = timeoutMillis;
+
+        synchronized (this.completion) {
+            while (completion == null && remainingTimeout > 0){
                 try {
-                Thread.sleep(interval);
+                    this.completion.wait(remainingTimeout);
                 } catch (InterruptedException e) {
                     throw new RuntimeException(e);
                 }
+
+                completion = this.completion.get();
+                remainingTimeout = timeoutMillis - (System.currentTimeMillis() - start);
+            }
         }
 
-        PromiseCompletion<T> completion = getCompletion();
+        if (completion == null)
-        if (completion == null) {
+            throw new TimeoutException("Promise timed out after " + timeoutMillis + "ms");
-            throw new IllegalStateException();
+
+        return joinCompletion(completion);
     }
 
-        if (completion.isError()) {
+    private T joinCompletion(PromiseCompletion<T> completion) {
+        if (completion.isError())
             throw new RuntimeException(completion.getException());
-        }
 
         return completion.getResult();
     }
@@ -275,15 +288,21 @@ public abstract class AbstractPromise<T> implements Promise<T> {
 
     @Override
     public @NotNull Promise<T> logExceptions() {
+        return logExceptions("Exception caught in promise chain");
+    }
+
+    @Override
+    public @NotNull Promise<T> logExceptions(@NotNull String message) {
         return addListener(ctx -> {
             if (ctx.isError()) {
-                getLogger().error("Exception caught in promise chain", ctx.getException());
+                getLogger().error(message, ctx.getException());
             }
         });
     }
 
     @Override
     public @NotNull Promise<T> addListener(@NotNull PromiseListener<T> listener) {
+        synchronized (completion) {
             if (isCompleted()) {
                 getExecutor().runAsync(() -> {
                     try {
@@ -292,10 +311,11 @@ public abstract class AbstractPromise<T> implements Promise<T> {
                     } catch (Exception e) {
                         getLogger().error("Exception caught in promise listener", e);
                     }
-            }, 0L, TimeUnit.MILLISECONDS);
+                });
             } else {
                 getListeners().add(listener);
             }
+        }
 
         return this;
     }
@@ -316,24 +336,11 @@ public abstract class AbstractPromise<T> implements Promise<T> {
         return timeout(ms, TimeUnit.MILLISECONDS);
     }
 
-    protected void handleCompletion(@NotNull PromiseCompletion<T> ctx) {
+    private void handleCompletion(@NotNull PromiseCompletion<T> ctx) {
-        AtomicBoolean success = new AtomicBoolean();
+        synchronized (completion) {
-        completion.getAndUpdate(c -> {
+            if (!setCompletion(ctx)) return;
-            if (c == null) {
-                success.set(true);
-                return ctx;
-            } else {
-                success.set(false);
-                return c;
-            }
-        });
 
-        if (success.get()) {
+            completion.notifyAll();
-            handleCompletion0(ctx);
-        }
-    }
-
-    protected void handleCompletion0(@NotNull PromiseCompletion<T> ctx) {
             getExecutor().runAsync(() -> {
                 for (PromiseListener<T> listener : getListeners()) {
                     if (!ctx.isActive()) return;
@@ -344,7 +351,12 @@ public abstract class AbstractPromise<T> implements Promise<T> {
                         getLogger().error("Exception caught in promise listener", e);
                     }
                 }
-        }, 0L, TimeUnit.MILLISECONDS);
+            });
+        }
+    }
+
+    private boolean setCompletion(PromiseCompletion<T> completion) {
+        return this.completion.compareAndSet(null, completion);
     }
 
     @Override
@@ -367,7 +379,7 @@ public abstract class AbstractPromise<T> implements Promise<T> {
         return completion.get();
     }
 
-    protected Collection<PromiseListener<T>> getListeners() {
+    private Collection<PromiseListener<T>> getListeners() {
         return listeners;
     }
 

futur-api/src/main/java/dev/tommyjs/futur/promise/Promise.java

@@ -31,8 +31,11 @@ public interface Promise<T> {
 
     PromiseFactory getFactory();
 
+    @Deprecated
     T join(long interval, long timeout) throws TimeoutException;
 
+    T join(long timeout) throws TimeoutException;
+
     @NotNull Promise<Void> thenRunSync(@NotNull ExceptionalRunnable task);
 
     @NotNull Promise<Void> thenRunDelayedSync(@NotNull ExceptionalRunnable task, long delay, @NotNull TimeUnit unit);
@@ -73,6 +76,8 @@ public interface Promise<T> {
 
     @NotNull Promise<T> logExceptions();
 
+    @NotNull Promise<T> logExceptions(@NotNull String message);
+
     @NotNull Promise<T> addListener(@NotNull PromiseListener<T> listener);
 
     @NotNull Promise<T> timeout(long time, @NotNull TimeUnit unit);

futur-api/src/main/java/dev/tommyjs/futur/promise/Promises.java

@@ -42,15 +42,13 @@ public class Promises {
     }
 
     public static <K, V> @NotNull Promise<Map<K, V>> combine(@NotNull Map<K, Promise<V>> promises, long timeout, @Nullable BiConsumer<K, Throwable> exceptionHandler, PromiseFactory factory) {
-        Map<K, V> map = new HashMap<>();
+        if (promises.isEmpty()) return factory.resolve(Collections.emptyMap());
-        ReentrantLock lock = new ReentrantLock();
 
+        Map<K, V> map = new HashMap<>();
         Promise<Map<K, V>> promise = factory.unresolved();
         for (Map.Entry<K, Promise<V>> entry : promises.entrySet()) {
             entry.getValue().addListener((ctx) -> {
-                lock.lock();
+                synchronized (map) {
-
-                try {
                     if (ctx.isError()) {
                         if (exceptionHandler == null) {
                             //noinspection ConstantConditions
@@ -63,8 +61,6 @@ public class Promises {
                         map.put(entry.getKey(), ctx.getResult());
                     }
                     if (map.size() == promises.size()) promise.complete(map);
-                } finally {
-                    lock.unlock();
                 }
             });
         }
@@ -105,6 +101,8 @@ public class Promises {
     }
 
     public static @NotNull Promise<Void> all(@NotNull List<Promise<?>> promises, PromiseFactory factory) {
+        if (promises.isEmpty()) return factory.resolve(null);
+
         Promise<Void> promise = factory.unresolved();
         for (Promise<?> p : promises) {
             p.addListener((ctx) -> {