basic 1.2.0 changes

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

@@ -0,0 +1,429 @@
+package dev.tommyjs.futur.promise;
+
+import dev.tommyjs.futur.function.ExceptionalConsumer;
+import dev.tommyjs.futur.function.ExceptionalFunction;
+import dev.tommyjs.futur.function.ExceptionalRunnable;
+import dev.tommyjs.futur.function.ExceptionalSupplier;
+import dev.tommyjs.futur.scheduler.Scheduler;
+import dev.tommyjs.futur.trace.ExecutorTrace;
+import dev.tommyjs.futur.trace.TraceUtil;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.concurrent.ConcurrentLinkedQueue;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.stream.Stream;
+
+public abstract class AbstractPromise<T> implements Promise<T> {
+
+    private static final String PACKAGE;
+
+    static {
+        String[] packageElements = AbstractPromise.class.getPackageName().split("\\.");
+        int i = 0;
+
+        StringBuilder packageBuilder = new StringBuilder();
+        while (i < 3) {
+            packageBuilder.append(packageElements[i]);
+            i++;
+        }
+
+        PACKAGE = packageBuilder.toString();
+    }
+
+    private final Collection<PromiseListener<T>> listeners;
+    private final StackTraceElement[] stackTrace;
+
+    private @Nullable PromiseCompletion<T> completion;
+
+    public AbstractPromise() {
+        this.listeners = new ConcurrentLinkedQueue<>();
+        this.completion = null;
+        this.stackTrace = Arrays.stream(Thread.currentThread().getStackTrace())
+            .filter(v -> !v.getClassName().startsWith(PACKAGE))
+            .toArray(StackTraceElement[]::new);
+    }
+    
+    protected abstract Scheduler getScheduler();
+
+    protected abstract Logger getLogger();
+
+    @Override
+    public T join(long interval, long timeout) throws TimeoutException {
+        long start = System.currentTimeMillis();
+        while (!isCompleted()) {
+            if (System.currentTimeMillis() > start + timeout)
+                throw new TimeoutException("Promise timed out after " + timeout + "ms");
+
+            try {
+                Thread.sleep(interval);
+            } catch (InterruptedException e) {
+                throw new RuntimeException(e);
+            }
+        }
+
+        PromiseCompletion<T> completion = getCompletion();
+        if (completion == null) {
+            throw new IllegalStateException();
+        }
+
+        if (completion.isError()) {
+            throw new RuntimeException(completion.getException());
+        }
+
+        return completion.getResult();
+    }
+
+    @Override
+    public @NotNull Promise<Void> thenRunSync(@NotNull ExceptionalRunnable task) {
+        return thenApplySync(result -> {
+            task.run();
+            return null;
+        }, TraceUtil.getTrace(task));
+    }
+
+    @Override
+    public @NotNull Promise<Void> thenRunDelayedSync(@NotNull ExceptionalRunnable task, long delay, @NotNull TimeUnit unit) {
+        return thenApplyDelayedSync(result -> {
+            task.run();
+            return null;
+        }, delay, unit, TraceUtil.getTrace(task));
+    }
+
+    @Override
+    public @NotNull Promise<Void> thenConsumeSync(@NotNull ExceptionalConsumer<T> task) {
+        return thenApplySync(result -> {
+            task.accept(result);
+            return null;
+        }, TraceUtil.getTrace(task));
+    }
+
+    @Override
+    public @NotNull Promise<Void> thenConsumeDelayedSync(@NotNull ExceptionalConsumer<T> task, long delay, @NotNull TimeUnit unit) {
+        return thenApplyDelayedSync(result -> {
+            task.accept(result);
+            return null;
+        }, delay, unit, TraceUtil.getTrace(task));
+    }
+
+    @Override
+    public <V> @NotNull Promise<V> thenSupplySync(@NotNull ExceptionalSupplier<V> task) {
+        return thenApplySync(result -> task.get(), TraceUtil.getTrace(task));
+    }
+
+    @Override
+    public <V> @NotNull Promise<V> thenSupplyDelayedSync(@NotNull ExceptionalSupplier<V> task, long delay, @NotNull TimeUnit unit) {
+        return thenApplyDelayedSync(result -> task.get(), delay, unit, TraceUtil.getTrace(task));
+    }
+    
+    protected <V> @NotNull Promise<V> thenApplySync(@NotNull ExceptionalFunction<T, V> task, @NotNull ExecutorTrace trace) {
+        Promise<V> promise = getFactory().unresolved();
+        addListener(ctx -> {
+            if (ctx.isError()) {
+                //noinspection ConstantConditions
+                promise.completeExceptionally(ctx.getException());
+                return;
+            }
+
+            Runnable runnable = createRunnable(ctx, promise, task);
+            getScheduler().runSync(runnable, trace);
+        });
+
+        return promise;
+    }
+
+    @Override
+    public <V> @NotNull Promise<V> thenApplySync(@NotNull ExceptionalFunction<T, V> task) {
+        return thenApplySync(task, TraceUtil.getTrace(task));
+    }
+
+    @Override
+    public <V> @NotNull Promise<V> thenApplyDelayedSync(@NotNull ExceptionalFunction<T, V> task, long delay, @NotNull TimeUnit unit, @NotNull ExecutorTrace trace) {
+        Promise<V> promise = getFactory().unresolved();
+        addListener(ctx -> {
+            if (ctx.isError()) {
+                //noinspection ConstantConditions
+                promise.completeExceptionally(ctx.getException());
+                return;
+            }
+
+            Runnable runnable = createRunnable(ctx, promise, task);
+            getScheduler().runDelayedSync(runnable, delay, unit, trace);
+        });
+
+        return promise;
+    }
+
+    @Override
+    public <V> @NotNull Promise<V> thenApplyDelayedSync(@NotNull ExceptionalFunction<T, V> task, long delay, @NotNull TimeUnit unit) {
+        return thenApplyDelayedSync(task, delay, unit, TraceUtil.getTrace(task));
+    }
+
+    @Override
+    public <V> @NotNull Promise<V> thenComposeSync(@NotNull ExceptionalFunction<T, @NotNull Promise<V>> task) {
+        Promise<V> promise = getFactory().unresolved();
+        thenApplySync(task, TraceUtil.getTrace(task)).thenConsumeAsync(nestedPromise -> {
+            nestedPromise.addListener(ctx1 -> {
+                if (ctx1.isError()) {
+                    //noinspection ConstantConditions
+                    promise.completeExceptionally(ctx1.getException());
+                    return;
+                }
+
+                promise.complete(ctx1.getResult());
+            });
+        }).addListener(ctx2 -> {
+            if (ctx2.isError()) {
+                //noinspection ConstantConditions
+                promise.completeExceptionally(ctx2.getException());
+            }
+        });
+
+        return promise;
+    }
+
+    @Override
+    public @NotNull Promise<Void> thenRunAsync(@NotNull ExceptionalRunnable task) {
+        return thenApplyAsync(result -> {
+            task.run();
+            return null;
+        }, TraceUtil.getTrace(task));
+    }
+
+    @Override
+    public @NotNull Promise<Void> thenRunDelayedAsync(@NotNull ExceptionalRunnable task, long delay, @NotNull TimeUnit unit) {
+        return thenApplyDelayedAsync(result -> {
+            task.run();
+            return null;
+        }, delay, unit, TraceUtil.getTrace(task));
+    }
+
+    @Override
+    public @NotNull Promise<Void> thenConsumeAsync(@NotNull ExceptionalConsumer<T> task) {
+        return thenApplyAsync(result -> {
+            task.accept(result);
+            return null;
+        }, TraceUtil.getTrace(task));
+    }
+
+    @Override
+    public @NotNull Promise<Void> thenConsumeDelayedAsync(@NotNull ExceptionalConsumer<T> task, long delay, @NotNull TimeUnit unit) {
+        return thenApplyDelayedAsync(result -> {
+            task.accept(result);
+            return null;
+        }, delay, unit, TraceUtil.getTrace(task));
+    }
+
+    @Override
+    public <V> @NotNull Promise<V> thenSupplyAsync(@NotNull ExceptionalSupplier<V> task) {
+        return thenApplyAsync(result -> task.get(), TraceUtil.getTrace(task));
+    }
+
+    @Override
+    public <V> @NotNull Promise<V> thenSupplyDelayedAsync(@NotNull ExceptionalSupplier<V> task, long delay, @NotNull TimeUnit unit) {
+        return thenApplyDelayedAsync(result -> task.get(), delay, unit, TraceUtil.getTrace(task));
+    }
+
+    @Override
+    public @NotNull Promise<T> thenPopulateReference(@NotNull AtomicReference<T> reference) {
+        return thenApplyAsync((result) -> {
+            reference.set(result);
+            return result;
+        });
+    }
+    
+    protected <V> @NotNull Promise<V> thenApplyAsync(@NotNull ExceptionalFunction<T, V> task, @NotNull ExecutorTrace trace) {
+        Promise<V> promise = getFactory().unresolved();
+        addListener(ctx -> {
+            if (ctx.isError()) {
+                //noinspection ConstantConditions
+                promise.completeExceptionally(ctx.getException());
+                return;
+            }
+
+            Runnable runnable = createRunnable(ctx, promise, task);
+            getScheduler().runAsync(runnable, trace);
+        });
+
+        return promise;
+    }
+
+    @Override
+    public <V> @NotNull Promise<V> thenApplyAsync(@NotNull ExceptionalFunction<T, V> task) {
+        return thenApplyAsync(task, TraceUtil.getTrace(task));
+    }
+
+    @Override
+    public <V> @NotNull Promise<V> thenApplyDelayedAsync(@NotNull ExceptionalFunction<T, V> task, long delay, @NotNull TimeUnit unit, @NotNull ExecutorTrace trace) {
+        Promise<V> promise = getFactory().unresolved();
+        addListener(ctx -> {
+            Runnable runnable = createRunnable(ctx, promise, task);
+            getScheduler().runDelayedAsync(runnable, delay, unit, trace);
+        });
+
+        return promise;
+    }
+
+    @Override
+    public <V> @NotNull Promise<V> thenApplyDelayedAsync(@NotNull ExceptionalFunction<T, V> task, long delay, @NotNull TimeUnit unit) {
+        return thenApplyDelayedAsync(task, delay, unit, TraceUtil.getTrace(task));
+    }
+
+    @Override
+    public <V> @NotNull Promise<V> thenCompose(@NotNull ExceptionalFunction<T, Promise<V>> task) {
+        return this.thenComposeAsync(task);
+    }
+
+    @Override
+    public <V> @NotNull Promise<V> thenComposeAsync(@NotNull ExceptionalFunction<T, Promise<V>> task) {
+        Promise<V> promise = getFactory().unresolved();
+        thenApplyAsync(task, TraceUtil.getTrace(task)).thenConsumeAsync(nestedPromise -> {
+            nestedPromise.addListener(ctx1 -> {
+                if (ctx1.isError()) {
+                    //noinspection ConstantConditions
+                    promise.completeExceptionally(ctx1.getException());
+                    return;
+                }
+
+                promise.complete(ctx1.getResult());
+            });
+        }).addListener(ctx2 -> {
+            if (ctx2.isError()) {
+                //noinspection ConstantConditions
+                promise.completeExceptionally(ctx2.getException());
+            }
+        });
+
+        return promise;
+    }
+
+    private <V> @NotNull Runnable createRunnable(@NotNull PromiseCompletion<T> ctx, @NotNull Promise<V> promise, @NotNull ExceptionalFunction<T, V> task) {
+        return () -> {
+            if (ctx.isError()) {
+                //noinspection ConstantConditions
+                promise.completeExceptionally(ctx.getException());
+                return;
+            }
+
+            try {
+                V result = task.apply(ctx.getResult());
+                promise.complete(result);
+            } catch (Exception e) {
+                promise.completeExceptionally(e, true);
+            }
+        };
+    }
+
+    @Override
+    public @NotNull Promise<T> logExceptions() {
+        return addListener(ctx -> {
+            if (ctx.isError()) {
+                getLogger().error("Exception caught in promise chain", ctx.getException());
+            }
+        });
+    }
+
+    @Override
+    public @NotNull Promise<T> addListener(@NotNull PromiseListener<T> listener) {
+        if (isCompleted()) {
+            getScheduler().runAsync(() -> {
+                try {
+                    //noinspection ConstantConditions
+                    listener.handle(getCompletion());
+                } catch (Exception e) {
+                    getLogger().error("Exception caught in promise listener", e);
+                }
+            }, TraceUtil.getTrace(listener));
+        } else {
+            getListeners().add(listener);
+        }
+
+        return this;
+    }
+
+    @Override
+    public @NotNull Promise<T> timeout(long time, @NotNull TimeUnit unit) {
+        Runnable func = () -> {
+            if (!isCompleted()) {
+                completeExceptionally(new TimeoutException("Promise timed out after " + time + " " + unit), true);
+            }
+        };
+
+        getScheduler().runDelayedAsync(func, time, unit, TraceUtil.getTrace(func));
+
+        return this;
+    }
+
+    @Override
+    public @NotNull Promise<T> timeout(long ms) {
+        return timeout(ms, TimeUnit.MILLISECONDS);
+    }
+
+    protected void handleCompletion(@NotNull PromiseCompletion<T> ctx) {
+        if (this.isCompleted()) return;
+        setCompletion(ctx);
+
+        Runnable func = () -> {
+            for (PromiseListener<T> listener : getListeners()) {
+                if (!ctx.isActive()) return;
+
+                try {
+                    listener.handle(ctx);
+                } catch (Exception e) {
+                    getLogger().error("Exception caught in promise listener", e);
+                }
+            }
+        };
+
+        getScheduler().runAsync(func, TraceUtil.getTrace(func));
+    }
+
+    @Override
+    public void complete(@Nullable T result) {
+        handleCompletion(new PromiseCompletion<>(result));
+    }
+
+    @Override
+    public void completeExceptionally(@NotNull Throwable result, boolean appendStacktrace) {
+        if (appendStacktrace && this.stackTrace != null) {
+            result.setStackTrace(Stream.of(result.getStackTrace(), this.stackTrace)
+                .flatMap(Stream::of)
+                .filter(v -> !v.getClassName().startsWith(PACKAGE))
+                .filter(v -> !v.getClassName().startsWith("java.lang.Thread"))
+                .filter(v -> !v.getClassName().startsWith("java.util.concurrent"))
+                .toArray(StackTraceElement[]::new));
+        }
+
+        handleCompletion(new PromiseCompletion<>(result));
+    }
+
+    @Override
+    public void completeExceptionally(@NotNull Throwable result) {
+        completeExceptionally(result, false);
+    }
+
+    @Override
+    public boolean isCompleted() {
+        return getCompletion() != null;
+    }
+
+    protected Collection<PromiseListener<T>> getListeners() {
+        return listeners;
+    }
+
+    @Override
+    public @Nullable PromiseCompletion<T> getCompletion() {
+        return completion;
+    }
+
+    protected void setCompletion(@NotNull PromiseCompletion<T> completion) {
+        this.completion = completion;
+    }
+
+}

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

@@ -0,0 +1,33 @@
+package dev.tommyjs.futur.promise;
+
+import dev.tommyjs.futur.scheduler.Scheduler;
+import org.slf4j.Logger;
+
+public class PooledPromise<T> extends AbstractPromise<T> {
+
+    private final Scheduler scheduler;
+    private final Logger logger;
+    private final PromiseFactory factory;
+
+    public PooledPromise(Scheduler scheduler, Logger logger, PromiseFactory factory) {
+        this.scheduler = scheduler;
+        this.logger = logger;
+        this.factory = factory;
+    }
+
+    @Override
+    protected Scheduler getScheduler() {
+        return scheduler;
+    }
+
+    @Override
+    protected Logger getLogger() {
+        return logger;
+    }
+
+    @Override
+    public PromiseFactory getFactory() {
+        return factory;
+    }
+
+}

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

@@ -0,0 +1,41 @@
+package dev.tommyjs.futur.promise;
+
+import dev.tommyjs.futur.scheduler.Scheduler;
+import org.jetbrains.annotations.NotNull;
+import org.slf4j.Logger;
+
+public class PooledPromiseFactory implements PromiseFactory {
+
+    private final Scheduler scheduler;
+    private final Logger logger;
+
+    public PooledPromiseFactory(Scheduler scheduler, Logger logger) {
+        this.scheduler = scheduler;
+        this.logger = logger;
+    }
+
+    @Override
+    public @NotNull <T> Promise<T> resolve(T value) {
+        AbstractPromise<T> promise = new PooledPromise<>(scheduler, logger, this);
+        promise.setCompletion(new PromiseCompletion<>(value));
+        return promise;
+    }
+
+    @Override
+    public @NotNull <T> Promise<T> unresolved() {
+        return new PooledPromise<>(scheduler, logger, this);
+    }
+
+    @Override
+    public @NotNull <T> Promise<T> error(Throwable error) {
+        AbstractPromise<T> promise = new PooledPromise<>(scheduler, logger, this);
+        promise.completeExceptionally(error);
+        return promise;
+    }
+
+    @Override
+    public @NotNull Promise<Void> start() {
+        return resolve(null);
+    }
+
+}

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

@@ -4,406 +4,109 @@ import dev.tommyjs.futur.function.ExceptionalConsumer;
 import dev.tommyjs.futur.function.ExceptionalFunction;
 import dev.tommyjs.futur.function.ExceptionalRunnable;
 import dev.tommyjs.futur.function.ExceptionalSupplier;
-import dev.tommyjs.futur.scheduler.Schedulers;
 import dev.tommyjs.futur.trace.ExecutorTrace;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicReference;
-import java.util.stream.Stream;
 
-public class Promise<T> {
+public interface Promise<T> {
 
-    private static final String PACKAGE;
-    private static final Logger LOGGER = LoggerFactory.getLogger(Promise.class);
-
-    static {
-        String[] packageElements = Promise.class.getPackageName().split("\\.");
-        int i = 0;
-
-        StringBuilder packageBuilder = new StringBuilder();
-        while (i < 3) {
-            packageBuilder.append(packageElements[i]);
-            i++;
-        }
-
-        PACKAGE = packageBuilder.toString();
+    static <T> @NotNull Promise<T> resolve(T value, PromiseFactory factory) {
+        return factory.resolve(value);
     }
 
-    private final Collection<PromiseListener<T>> listeners;
-    private final StackTraceElement[] stackTrace;
-
-    private @Nullable PromiseCompletion<T> completion;
-
-    public Promise() {
-        this.listeners = new ConcurrentLinkedQueue<>();
-        this.completion = null;
-        this.stackTrace = Arrays.stream(Thread.currentThread().getStackTrace())
-            .filter(v -> !v.getClassName().startsWith(PACKAGE))
-            .toArray(StackTraceElement[]::new);
+    static <T> @NotNull Promise<T> error(Throwable error, PromiseFactory factory) {
+        return factory.error(error);
     }
 
-    public T join(long interval, long timeout) throws TimeoutException {
-        long start = System.currentTimeMillis();
-        while (!isCompleted()) {
-            if (System.currentTimeMillis() > start + timeout)
-                throw new TimeoutException("Promise timed out after " + timeout + "ms");
-
-            try {
-                Thread.sleep(interval);
-            } catch (InterruptedException e) {
-                throw new RuntimeException(e);
-            }
-        }
-
-        PromiseCompletion<T> completion = getCompletion();
-        if (completion == null) {
-            throw new IllegalStateException();
-        }
-
-        if (completion.isError()) {
-            throw new RuntimeException(completion.getException());
-        }
-
-        return completion.getResult();
+    static @NotNull Promise<Void> start(PromiseFactory factory) {
+        return factory.start();
     }
 
-    public @NotNull Promise<Void> thenRunSync(@NotNull ExceptionalRunnable task) {
-        return thenApplySync(result -> {
-            task.run();
-            return null;
-        }, Schedulers.getTrace(task));
+    static <T> @NotNull Promise<T> resolve(T value) {
+        return resolve(value, UnpooledPromiseFactory.INSTANCE);
     }
 
-    public @NotNull Promise<Void> thenRunDelayedSync(@NotNull ExceptionalRunnable task, long delay, @NotNull TimeUnit unit) {
-        return thenApplyDelayedSync(result -> {
-            task.run();
-            return null;
-        }, delay, unit, Schedulers.getTrace(task));
+    static <T> @NotNull Promise<T> error(Throwable error) {
+        return error(error, UnpooledPromiseFactory.INSTANCE);
     }
 
-    public @NotNull Promise<Void> thenConsumeSync(@NotNull ExceptionalConsumer<T> task) {
-        return thenApplySync(result -> {
-            task.accept(result);
-            return null;
-        }, Schedulers.getTrace(task));
+    static @NotNull Promise<Void> start() {
+        return start(UnpooledPromiseFactory.INSTANCE);
     }
 
-    public @NotNull Promise<Void> thenConsumeDelayedSync(@NotNull ExceptionalConsumer<T> task, long delay, @NotNull TimeUnit unit) {
-        return thenApplyDelayedSync(result -> {
-            task.accept(result);
-            return null;
-        }, delay, unit, Schedulers.getTrace(task));
+    @Deprecated
+    static <T> @NotNull Promise<T> start(T start) {
+        return resolve(start);
     }
 
-    public <V> @NotNull Promise<V> thenSupplySync(@NotNull ExceptionalSupplier<V> task) {
-        return thenApplySync(result -> task.get(), Schedulers.getTrace(task));
-    }
+    PromiseFactory getFactory();
 
-    public <V> @NotNull Promise<V> thenSupplyDelayedSync(@NotNull ExceptionalSupplier<V> task, long delay, @NotNull TimeUnit unit) {
-        return thenApplyDelayedSync(result -> task.get(), delay, unit, Schedulers.getTrace(task));
-    }
+    T join(long interval, long timeout) throws TimeoutException;
 
-    public <V> @NotNull Promise<V> thenApplySync(@NotNull ExceptionalFunction<T, V> task, @NotNull ExecutorTrace trace) {
-        Promise<V> promise = new Promise<>();
-        addListener(ctx -> {
-            if (ctx.isError()) {
-                //noinspection ConstantConditions
-                promise.completeExceptionally(ctx.getException());
-                return;
-            }
+    @NotNull Promise<Void> thenRunSync(@NotNull ExceptionalRunnable task);
 
-            Runnable runnable = createRunnable(ctx, promise, task);
-            Schedulers.runSync(runnable, trace);
-        });
+    @NotNull Promise<Void> thenRunDelayedSync(@NotNull ExceptionalRunnable task, long delay, @NotNull TimeUnit unit);
 
-        return promise;
-    }
+    @NotNull Promise<Void> thenConsumeSync(@NotNull ExceptionalConsumer<T> task);
 
-    public <V> @NotNull Promise<V> thenApplySync(@NotNull ExceptionalFunction<T, V> task) {
-        return thenApplySync(task, Schedulers.getTrace(task));
-    }
+    @NotNull Promise<Void> thenConsumeDelayedSync(@NotNull ExceptionalConsumer<T> task, long delay, @NotNull TimeUnit unit);
 
-    public <V> @NotNull Promise<V> thenApplyDelayedSync(@NotNull ExceptionalFunction<T, V> task, long delay, @NotNull TimeUnit unit, @NotNull ExecutorTrace trace) {
-        Promise<V> promise = new Promise<>();
-        addListener(ctx -> {
-            if (ctx.isError()) {
-                //noinspection ConstantConditions
-                promise.completeExceptionally(ctx.getException());
-                return;
-            }
+    <V> @NotNull Promise<V> thenSupplySync(@NotNull ExceptionalSupplier<V> task);
 
-            Runnable runnable = createRunnable(ctx, promise, task);
-            Schedulers.runDelayedSync(runnable, delay, unit, trace);
-        });
+    <V> @NotNull Promise<V> thenSupplyDelayedSync(@NotNull ExceptionalSupplier<V> task, long delay, @NotNull TimeUnit unit);
 
-        return promise;
-    }
+    <V> @NotNull Promise<V> thenApplySync(@NotNull ExceptionalFunction<T, V> task);
 
-    public <V> @NotNull Promise<V> thenApplyDelayedSync(@NotNull ExceptionalFunction<T, V> task, long delay, @NotNull TimeUnit unit) {
-        return thenApplyDelayedSync(task, delay, unit, Schedulers.getTrace(task));
-    }
+    <V> @NotNull Promise<V> thenApplyDelayedSync(@NotNull ExceptionalFunction<T, V> task, long delay, @NotNull TimeUnit unit, @NotNull ExecutorTrace trace);
 
-    public <V> @NotNull Promise<V> thenComposeSync(@NotNull ExceptionalFunction<T, @NotNull Promise<V>> task) {
-        Promise<V> promise = new Promise<>();
-        thenApplySync(task, Schedulers.getTrace(task)).thenConsumeAsync(nestedPromise -> {
-            nestedPromise.addListener(ctx1 -> {
-                if (ctx1.isError()) {
-                    //noinspection ConstantConditions
-                    promise.completeExceptionally(ctx1.getException());
-                    return;
-                }
+    <V> @NotNull Promise<V> thenApplyDelayedSync(@NotNull ExceptionalFunction<T, V> task, long delay, @NotNull TimeUnit unit);
 
-                promise.complete(ctx1.getResult());
-            });
-        }).addListener(ctx2 -> {
-            if (ctx2.isError()) {
-                //noinspection ConstantConditions
-                promise.completeExceptionally(ctx2.getException());
-            }
-        });
+    <V> @NotNull Promise<V> thenComposeSync(@NotNull ExceptionalFunction<T, @NotNull Promise<V>> task);
 
-        return promise;
-    }
+    @NotNull Promise<Void> thenRunAsync(@NotNull ExceptionalRunnable task);
 
-    public @NotNull Promise<Void> thenRunAsync(@NotNull ExceptionalRunnable task) {
-        return thenApplyAsync(result -> {
-            task.run();
-            return null;
-        }, Schedulers.getTrace(task));
-    }
+    @NotNull Promise<Void> thenRunDelayedAsync(@NotNull ExceptionalRunnable task, long delay, @NotNull TimeUnit unit);
 
-    public @NotNull Promise<Void> thenRunDelayedAsync(@NotNull ExceptionalRunnable task, long delay, @NotNull TimeUnit unit) {
-        return thenApplyDelayedAsync(result -> {
-            task.run();
-            return null;
-        }, delay, unit, Schedulers.getTrace(task));
-    }
+    @NotNull Promise<Void> thenConsumeAsync(@NotNull ExceptionalConsumer<T> task);
 
-    public @NotNull Promise<Void> thenConsumeAsync(@NotNull ExceptionalConsumer<T> task) {
-        return thenApplyAsync(result -> {
-            task.accept(result);
-            return null;
-        }, Schedulers.getTrace(task));
-    }
+    @NotNull Promise<Void> thenConsumeDelayedAsync(@NotNull ExceptionalConsumer<T> task, long delay, @NotNull TimeUnit unit);
 
-    public @NotNull Promise<Void> thenConsumeDelayedAsync(@NotNull ExceptionalConsumer<T> task, long delay, @NotNull TimeUnit unit) {
-        return thenApplyDelayedAsync(result -> {
-            task.accept(result);
-            return null;
-        }, delay, unit, Schedulers.getTrace(task));
-    }
+    <V> @NotNull Promise<V> thenSupplyAsync(@NotNull ExceptionalSupplier<V> task);
 
-    @Deprecated(forRemoval = true)
-    public @NotNull Promise<Void> thenConsumerDelayedAsync(@NotNull ExceptionalConsumer<T> task, long delay, @NotNull TimeUnit unit) {
-        return thenConsumeDelayedAsync(task, delay, unit);
-    }
+    <V> @NotNull Promise<V> thenSupplyDelayedAsync(@NotNull ExceptionalSupplier<V> task, long delay, @NotNull TimeUnit unit);
 
-    public <V> @NotNull Promise<V> thenSupplyAsync(@NotNull ExceptionalSupplier<V> task) {
-        return thenApplyAsync(result -> task.get(), Schedulers.getTrace(task));
-    }
+    @NotNull Promise<T> thenPopulateReference(@NotNull AtomicReference<T> reference);
 
-    public <V> @NotNull Promise<V> thenSupplyDelayedAsync(@NotNull ExceptionalSupplier<V> task, long delay, @NotNull TimeUnit unit) {
-        return thenApplyDelayedAsync(result -> task.get(), delay, unit, Schedulers.getTrace(task));
-    }
+    <V> @NotNull Promise<V> thenApplyAsync(@NotNull ExceptionalFunction<T, V> task);
 
-    public @NotNull Promise<T> thenPopulateReference(@NotNull AtomicReference<T> reference) {
-        return thenApplyAsync((result) -> {
-            reference.set(result);
-            return result;
-        });
-    }
+    <V> @NotNull Promise<V> thenApplyDelayedAsync(@NotNull ExceptionalFunction<T, V> task, long delay, @NotNull TimeUnit unit, @NotNull ExecutorTrace trace);
 
-    public <V> @NotNull Promise<V> thenApplyAsync(@NotNull ExceptionalFunction<T, V> task, @NotNull ExecutorTrace trace) {
-        Promise<V> promise = new Promise<>();
-        addListener(ctx -> {
-            createRunnable(ctx, promise, task).run();
-        });
+    <V> @NotNull Promise<V> thenApplyDelayedAsync(@NotNull ExceptionalFunction<T, V> task, long delay, @NotNull TimeUnit unit);
 
-        return promise;
-    }
+    <V> @NotNull Promise<V> thenCompose(@NotNull ExceptionalFunction<T, Promise<V>> task);
 
-    public <V> @NotNull Promise<V> thenApplyAsync(@NotNull ExceptionalFunction<T, V> task) {
-        return thenApplyAsync(task, Schedulers.getTrace(task));
-    }
+    <V> @NotNull Promise<V> thenComposeAsync(@NotNull ExceptionalFunction<T, Promise<V>> task);
 
-    public <V> @NotNull Promise<V> thenApplyDelayedAsync(@NotNull ExceptionalFunction<T, V> task, long delay, @NotNull TimeUnit unit, @NotNull ExecutorTrace trace) {
-        Promise<V> promise = new Promise<>();
-        addListener(ctx -> {
-            Runnable runnable = createRunnable(ctx, promise, task);
-            Schedulers.runDelayedAsync(runnable, delay, unit, trace);
-        });
+    @NotNull Promise<T> logExceptions();
 
-        return promise;
-    }
+    @NotNull Promise<T> addListener(@NotNull PromiseListener<T> listener);
 
-    public <V> @NotNull Promise<V> thenApplyDelayedAsync(@NotNull ExceptionalFunction<T, V> task, long delay, @NotNull TimeUnit unit) {
-        return thenApplyDelayedAsync(task, delay, unit, Schedulers.getTrace(task));
-    }
+    @NotNull Promise<T> timeout(long time, @NotNull TimeUnit unit);
 
-    public <V> @NotNull Promise<V> thenCompose(@NotNull ExceptionalFunction<T, Promise<V>> task) {
-        return this.thenComposeAsync(task);
-    }
+    @NotNull Promise<T> timeout(long ms);
 
-    public <V> @NotNull Promise<V> thenComposeAsync(@NotNull ExceptionalFunction<T, Promise<V>> task) {
-        Promise<V> promise = new Promise<>();
-        thenApplyAsync(task, Schedulers.getTrace(task)).thenConsumeAsync(nestedPromise -> {
-            nestedPromise.addListener(ctx1 -> {
-                if (ctx1.isError()) {
-                    //noinspection ConstantConditions
-                    promise.completeExceptionally(ctx1.getException());
-                    return;
-                }
+    void complete(@Nullable T result);
 
-                promise.complete(ctx1.getResult());
-            });
-        }).addListener(ctx2 -> {
-            if (ctx2.isError()) {
-                //noinspection ConstantConditions
-                promise.completeExceptionally(ctx2.getException());
-            }
-        });
+    void completeExceptionally(@NotNull Throwable result, boolean appendStacktrace);
 
-        return promise;
-    }
+    void completeExceptionally(@NotNull Throwable result);
 
-    private <V> @NotNull Runnable createRunnable(@NotNull PromiseCompletion<T> ctx, @NotNull Promise<V> promise, @NotNull ExceptionalFunction<T, V> task) {
-        return () -> {
-            if (ctx.isError()) {
-                //noinspection ConstantConditions
-                promise.completeExceptionally(ctx.getException());
-                return;
-            }
+    boolean isCompleted();
 
-            try {
-                V result = task.apply(ctx.getResult());
-                promise.complete(result);
-            } catch (Exception e) {
-                promise.completeExceptionally(e, true);
-            }
-        };
-    }
-
-    public @NotNull Promise<T> logExceptions() {
-        return addListener(ctx -> {
-            if (ctx.isError()) {
-                LOGGER.error("Exception caught in promise pipeline", ctx.getException());
-            }
-        });
-    }
-
-    public @NotNull Promise<T> addListener(@NotNull PromiseListener<T> listener) {
-        if (isCompleted()) {
-            Schedulers.runAsync(() -> {
-                try {
-                    listener.handle(getCompletion());
-                } catch (Exception e) {
-                    LOGGER.error("Exception caught in promise listener", e);
-                }
-            }, Schedulers.getTrace(listener));
-        } else {
-            getListeners().add(listener);
-        }
-
-        return this;
-    }
-
-    public @NotNull Promise<T> timeout(long time, @NotNull TimeUnit unit) {
-        Schedulers.runDelayedAsync(() -> {
-            if (!isCompleted()) {
-                completeExceptionally(new TimeoutException("Promise timed out after " + time + " " + unit), true);
-            }
-        }, time, unit);
-
-        return this;
-    }
-
-    public @NotNull Promise<T> timeout(long ms) {
-        return timeout(ms, TimeUnit.MILLISECONDS);
-    }
-
-    protected void handleCompletion(@NotNull PromiseCompletion<T> ctx) {
-        if (this.isCompleted()) return;
-        setCompletion(ctx);
-
-        Schedulers.runAsync(() -> {
-            for (PromiseListener<T> listener : getListeners()) {
-                if (!ctx.isActive()) return;
-
-                try {
-                    listener.handle(ctx);
-                } catch (Exception e) {
-                    LOGGER.error("Exception caught in promise listener", e);
-                }
-            }
-        });
-    }
-
-    public void complete(@Nullable T result) {
-        handleCompletion(new PromiseCompletion<>(result));
-    }
-
-    public void completeExceptionally(@NotNull Throwable result, boolean appendStacktrace) {
-        if (appendStacktrace && this.stackTrace != null) {
-            result.setStackTrace(Stream.of(result.getStackTrace(), this.stackTrace)
-                .flatMap(Stream::of)
-                .filter(v -> !v.getClassName().startsWith(PACKAGE))
-                .filter(v -> !v.getClassName().startsWith("java.lang.Thread"))
-                .filter(v -> !v.getClassName().startsWith("java.util.concurrent"))
-                .toArray(StackTraceElement[]::new));
-        }
-
-        handleCompletion(new PromiseCompletion<>(result));
-    }
-
-    public void completeExceptionally(@NotNull Throwable result) {
-        completeExceptionally(result, false);
-    }
-
-    public boolean isCompleted() {
-        return getCompletion() != null;
-    }
-
-    protected Collection<PromiseListener<T>> getListeners() {
-        return listeners;
-    }
-
-    public @Nullable PromiseCompletion<T> getCompletion() {
-        return completion;
-    }
-
-    protected void setCompletion(@NotNull PromiseCompletion<T> completion) {
-        this.completion = completion;
-    }
-
-    public static <T> @NotNull Promise<T> resolve(T value) {
-        Promise<T> promise = new Promise<>();
-        promise.setCompletion(new PromiseCompletion<>(value));
-        return promise;
-    }
-
-    public static <T> @NotNull Promise<T> error(Throwable error) {
-        Promise<T> promise = new Promise<>();
-        promise.completeExceptionally(error);
-        return promise;
-    }
-
-    public static @NotNull Promise<Void> start() {
-        return Promise.resolve(null);
-    }
-
-    @Deprecated // use resolve()
-    public static <T> @NotNull Promise<T> start(T start) {
-        Promise<T> promise = new Promise<>();
-        promise.complete(start);
-        return promise;
-    }
+    @Nullable PromiseCompletion<T> getCompletion();
 
 }

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

@@ -0,0 +1,16 @@
+package dev.tommyjs.futur.promise;
+
+import org.jetbrains.annotations.NotNull;
+import org.slf4j.Logger;
+
+public interface PromiseFactory {
+
+    <T> @NotNull Promise<T> resolve(T value);
+
+    <T> @NotNull Promise<T> unresolved();
+
+    <T> @NotNull Promise<T> error(Throwable error);
+
+    @NotNull Promise<Void> start();
+
+}

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

@@ -3,6 +3,8 @@ package dev.tommyjs.futur.promise;
 import dev.tommyjs.futur.function.ExceptionalFunction;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import java.util.*;
 import java.util.concurrent.CompletableFuture;
@@ -13,8 +15,8 @@ import java.util.stream.Collectors;
 
 public class Promises {
 
-    public static <K, V> @NotNull Promise<Map.Entry<K, V>> combine(@NotNull Promise<K> p1, @NotNull Promise<V> p2) {
-        Promise<Map.Entry<K, V>> promise = new Promise<>();
+    public static <K, V> @NotNull Promise<Map.Entry<K, V>> combine(@NotNull Promise<K> p1, @NotNull Promise<V> p2, PromiseFactory factory) {
+        Promise<Map.Entry<K, V>> promise = factory.unresolved();
         p1.addListener(ctx -> {
             if (ctx.isError()) {
                 //noinspection ConstantConditions
@@ -37,13 +39,15 @@ public class Promises {
         return promise;
     }
 
-    public static <K, V> @NotNull Promise<Map<K, V>> combine(@NotNull Map<K, Promise<V>> promises, long timeout, @Nullable BiConsumer<K, Throwable> exceptionHandler) {
-        Map<K, V> map = new HashMap<>();
-        if (promises.isEmpty()) return Promise.resolve(map);
+    public static <K, V> @NotNull Promise<Map.Entry<K, V>> combine(@NotNull Promise<K> p1, @NotNull Promise<V> p2) {
+        return combine(p1, p2, p1.getFactory());
+    }
 
+    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<>();
         ReentrantLock lock = new ReentrantLock();
 
-        Promise<Map<K, V>> promise = new Promise<>();
+        Promise<Map<K, V>> promise = factory.unresolved();
         for (Map.Entry<K, Promise<V>> entry : promises.entrySet()) {
             entry.getValue().addListener((ctx) -> {
                 lock.lock();
@@ -69,19 +73,35 @@ public class Promises {
         return promise.timeout(timeout);
     }
 
+    public static <K, V> @NotNull Promise<Map<K, V>> combine(@NotNull Map<K, Promise<V>> promises, long timeout, @Nullable BiConsumer<K, Throwable> exceptionHandler) {
+        return combine(promises, timeout, exceptionHandler, obtainFactory(promises.values()));
+    }
+
+    public static <K, V> @NotNull Promise<Map<K, V>> combine(@NotNull Map<K, Promise<V>> promises, long timeout, boolean strict, PromiseFactory factory) {
+        return combine(promises, timeout, strict ? null : (_k, _v) -> {}, factory);
+    }
+
     public static <K, V> @NotNull Promise<Map<K, V>> combine(@NotNull Map<K, Promise<V>> promises, long timeout, boolean strict) {
-        return combine(promises, timeout, strict ? null : (_k, _v) -> {});
+        return combine(promises, timeout, strict, obtainFactory(promises.values()));
+    }
+
+    public static <K, V> @NotNull Promise<Map<K, V>> combine(@NotNull Map<K, Promise<V>> promises, long timeout, PromiseFactory factory) {
+        return combine(promises, timeout, true, factory);
     }
 
     public static <K, V> @NotNull Promise<Map<K, V>> combine(@NotNull Map<K, Promise<V>> promises, long timeout) {
-        return combine(promises, timeout, true);
+        return combine(promises, timeout, true, obtainFactory(promises.values()));
+    }
+
+    public static <K, V> @NotNull Promise<Map<K, V>> combine(@NotNull Map<K, Promise<V>> promises, PromiseFactory factory) {
+        return combine(promises, 1500L, true, factory);
     }
 
     public static <K, V> @NotNull Promise<Map<K, V>> combine(@NotNull Map<K, Promise<V>> promises) {
-        return combine(promises, 1500L, true);
+        return combine(promises, obtainFactory(promises.values()));
     }
 
-    public static <V> @NotNull Promise<List<V>> combine(@NotNull List<Promise<V>> promises, long timeout, boolean strict) {
+    public static <V> @NotNull Promise<List<V>> combine(@NotNull List<Promise<V>> promises, long timeout, boolean strict, PromiseFactory factory) {
         AtomicInteger index = new AtomicInteger();
         return combine(
             promises.stream()
@@ -96,18 +116,28 @@ public class Promises {
         );
     }
 
-    public static <V> @NotNull Promise<List<V>> combine(@NotNull List<Promise<V>> promises, long timeout) {
-        return combine(promises, timeout, true);
+    public static <V> @NotNull Promise<List<V>> combine(@NotNull List<Promise<V>> promises, long timeout, boolean strict) {
+        return combine(promises, timeout, strict, obtainFactory(promises));
     }
 
-    public static <V> @NotNull Promise<List<V>> combine(@NotNull List<Promise<V>> promises) {
+    public static <V> @NotNull Promise<List<V>> combine(@NotNull List<Promise<V>> promises, long timeout, PromiseFactory factory) {
+        return combine(promises, timeout, true, factory);
+    }
+
+    public static <V> @NotNull Promise<List<V>> combine(@NotNull List<Promise<V>> promises, long timeout) {
+        return combine(promises, timeout, obtainFactory(promises));
+    }
+
+    public static <V> @NotNull Promise<List<V>> combine(@NotNull List<Promise<V>> promises, PromiseFactory factory) {
         return combine(promises, 1500L, true);
     }
 
-    public static @NotNull Promise<Void> all(@NotNull List<Promise<?>> promises) {
-        if (promises.isEmpty()) return Promise.start();
+    public static <V> @NotNull Promise<List<V>> combine(@NotNull List<Promise<V>> promises) {
+        return combine(promises, obtainFactory(promises));
+    }
 
-        Promise<Void> promise = new Promise<>();
+    public static @NotNull Promise<Void> all(@NotNull List<Promise<?>> promises, PromiseFactory factory) {
+        Promise<Void> promise = factory.unresolved();
         for (Promise<?> p : promises) {
             p.addListener((ctx) -> {
                 if (ctx.isError()) {
@@ -121,30 +151,49 @@ public class Promises {
         return promise;
     }
 
-    public static @NotNull Promise<Void> all(@NotNull Promise<?>... promises) {
-        return all(Arrays.asList(promises));
+    public static @NotNull Promise<Void> all(@NotNull List<Promise<?>> promises) {
+        PromiseFactory factory;
+        if (promises.isEmpty()) {
+            factory = UnpooledPromiseFactory.INSTANCE;
+        } else {
+            factory = promises.get(0).getFactory();
+        }
+
+        return all(promises, factory);
     }
 
-    public static <K, V> @NotNull Promise<Map<K, V>> combine(@NotNull Collection<K> keys, @NotNull ExceptionalFunction<K, V> mapper, long timeout, boolean strict) {
+    public static <K, V> @NotNull Promise<Map<K, V>> combine(@NotNull Collection<K> keys, @NotNull ExceptionalFunction<K, V> mapper, long timeout, boolean strict, PromiseFactory factory) {
         Map<K, Promise<V>> promises = new HashMap<>();
         for (K key : keys) {
-            Promise<V> promise = Promise.resolve(key).thenApplyAsync(mapper);
+            Promise<V> promise = factory.resolve(key).thenApplyAsync(mapper);
             promises.put(key, promise);
         }
 
         return combine(promises, timeout, strict);
     }
 
+    public static <K, V> @NotNull Promise<Map<K, V>> combine(@NotNull Collection<K> keys, @NotNull ExceptionalFunction<K, V> mapper, long timeout, boolean strict) {
+        return combine(keys, mapper, timeout, strict, UnpooledPromiseFactory.INSTANCE);
+    }
+
+    public static <K, V> @NotNull Promise<Map<K, V>> combine(@NotNull Collection<K> keys, @NotNull ExceptionalFunction<K, V> mapper, long timeout, PromiseFactory factory) {
+        return combine(keys, mapper, timeout, true, factory);
+    }
+
     public static <K, V> @NotNull Promise<Map<K, V>> combine(@NotNull Collection<K> keys, @NotNull ExceptionalFunction<K, V> mapper, long timeout) {
-        return combine(keys, mapper, timeout, true);
+        return combine(keys, mapper, timeout, UnpooledPromiseFactory.INSTANCE);
+    }
+
+    public static <K, V> @NotNull Promise<Map<K, V>> combine(@NotNull Collection<K> keys, @NotNull ExceptionalFunction<K, V> mapper, PromiseFactory factory) {
+        return combine(keys, mapper, 1500L, true, factory);
     }
 
     public static <K, V> @NotNull Promise<Map<K, V>> combine(@NotNull Collection<K> keys, @NotNull ExceptionalFunction<K, V> mapper) {
-        return combine(keys, mapper, 1500L, true);
+        return combine(keys, mapper, UnpooledPromiseFactory.INSTANCE);
     }
 
-    public static @NotNull Promise<Void> erase(@NotNull Promise<?> p) {
-        Promise<Void> promise = new Promise<>();
+    public static @NotNull Promise<Void> erase(@NotNull Promise<?> p, PromiseFactory factory) {
+        Promise<Void> promise = factory.unresolved();
         p.addListener(ctx -> {
             if (ctx.isError()) {
                 //noinspection ConstantConditions
@@ -157,8 +206,12 @@ public class Promises {
         return promise;
     }
 
-    public static <T> @NotNull Promise<T> wrap(@NotNull CompletableFuture<T> future) {
-        Promise<T> promise = new Promise<>();
+    public static @NotNull Promise<Void> erase(@NotNull Promise<?> p) {
+        return erase(p, p.getFactory());
+    }
+
+    public static <T> @NotNull Promise<T> wrap(@NotNull CompletableFuture<T> future, PromiseFactory factory) {
+        Promise<T> promise = factory.unresolved();
         future.whenComplete((result, e) -> {
             if (e != null) {
                 promise.completeExceptionally(e);
@@ -170,4 +223,19 @@ public class Promises {
         return promise;
     }
 
+    public static <T> @NotNull Promise<T> wrap(@NotNull CompletableFuture<T> future) {
+        return wrap(future, UnpooledPromiseFactory.INSTANCE);
+    }
+
+    public static <T> PromiseFactory obtainFactory(Collection<Promise<T>> promises) {
+        PromiseFactory factory;
+        if (promises.isEmpty()) {
+            factory = UnpooledPromiseFactory.INSTANCE;
+        } else {
+            factory = promises.stream().findFirst().get().getFactory();
+        }
+
+        return factory;
+    }
+
 }

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

@@ -0,0 +1,23 @@
+package dev.tommyjs.futur.promise;
+
+import dev.tommyjs.futur.scheduler.Scheduler;
+import org.slf4j.Logger;
+
+public class UnpooledPromise<T> extends AbstractPromise<T> {
+
+    @Override
+    protected Scheduler getScheduler() {
+        return UnpooledPromiseFactory.SCHEDULER;
+    }
+
+    @Override
+    protected Logger getLogger() {
+        return UnpooledPromiseFactory.LOGGER;
+    }
+
+    @Override
+    public PromiseFactory getFactory() {
+        return UnpooledPromiseFactory.INSTANCE;
+    }
+
+}

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

@@ -0,0 +1,50 @@
+package dev.tommyjs.futur.promise;
+
+import dev.tommyjs.futur.scheduler.Scheduler;
+import dev.tommyjs.futur.scheduler.SingleExecutorScheduler;
+import org.jetbrains.annotations.NotNull;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.concurrent.Executors;
+
+public class UnpooledPromiseFactory implements PromiseFactory {
+
+    public static final @NotNull PromiseFactory INSTANCE;
+    public static final @NotNull Scheduler SCHEDULER;
+    public static final @NotNull Logger LOGGER;
+
+    static {
+        INSTANCE = new UnpooledPromiseFactory();
+        SCHEDULER = new SingleExecutorScheduler(Executors.newSingleThreadScheduledExecutor());
+        LOGGER = LoggerFactory.getLogger(UnpooledPromiseFactory.class);
+    }
+
+    private UnpooledPromiseFactory() {
+    }
+
+    @Override
+    public @NotNull <T> Promise<T> resolve(T value) {
+        AbstractPromise<T> promise = new UnpooledPromise<>();
+        promise.setCompletion(new PromiseCompletion<>(value));
+        return promise;
+    }
+
+    @Override
+    public @NotNull <T> Promise<T> unresolved() {
+        return new UnpooledPromise<>();
+    }
+
+    @Override
+    public @NotNull <T> Promise<T> error(Throwable error) {
+        AbstractPromise<T> promise = new UnpooledPromise<>();
+        promise.completeExceptionally(error);
+        return promise;
+    }
+
+    @Override
+    public @NotNull Promise<Void> start() {
+        return resolve(null);
+    }
+
+}

futur-api/src/main/java/dev/tommyjs/futur/scheduler/Scheduler.java

@@ -23,7 +23,7 @@ public interface Scheduler {
 
     void runRepeatingAsync(@NotNull Runnable task, long interval, @NotNull TimeUnit unit, @NotNull ExecutorTrace trace);
 
-    default @NotNull Runnable wrapExceptions(@NotNull Runnable task, @NotNull ExecutorTrace trace) {
+    static @NotNull Runnable wrapExceptions(@NotNull Runnable task, @NotNull ExecutorTrace trace) {
         return () -> {
             try {
                 task.run();

futur-api/src/main/java/dev/tommyjs/futur/scheduler/Schedulers.java

@@ -1,105 +0,0 @@
-package dev.tommyjs.futur.scheduler;
-
-import dev.tommyjs.futur.trace.ExecutorTrace;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-import java.util.concurrent.TimeUnit;
-
-@SuppressWarnings("ConstantConditions")
-public class Schedulers {
-
-    private static final Logger LOGGER = LoggerFactory.getLogger(Schedulers.class);
-
-    private static @Nullable Scheduler scheduler;
-
-    public static void runSync(@NotNull Runnable task, @NotNull ExecutorTrace trace) {
-        ensureLoaded();
-        getScheduler().runSync(task, trace);
-    }
-
-    public static void runSync(@NotNull Runnable task) {
-        ensureLoaded();
-        getScheduler().runSync(task, Schedulers.getTrace(task));
-    }
-
-    public static void runDelayedSync(@NotNull Runnable task, long delay, @NotNull TimeUnit unit, @NotNull ExecutorTrace trace) {
-        ensureLoaded();
-        getScheduler().runDelayedSync(task, delay, unit, trace);
-    }
-
-    public static void runDelayedSync(@NotNull Runnable task, long delay, @NotNull TimeUnit unit) {
-        ensureLoaded();
-        getScheduler().runDelayedSync(task, delay, unit, Schedulers.getTrace(task));
-    }
-
-    public static void runRepeatingSync(@NotNull Runnable task, long interval, @NotNull TimeUnit unit, @NotNull ExecutorTrace trace) {
-        ensureLoaded();
-        getScheduler().runRepeatingSync(task, interval, unit, trace);
-    }
-
-    public static void runRepeatingSync(@NotNull Runnable task, long interval, @NotNull TimeUnit unit) {
-        ensureLoaded();
-        getScheduler().runRepeatingSync(task, interval, unit, Schedulers.getTrace(task));
-    }
-
-    public static void runAsync(@NotNull Runnable task, @NotNull ExecutorTrace trace) {
-        ensureLoaded();
-        getScheduler().runAsync(task, trace);
-    }
-
-    public static void runAsync(@NotNull Runnable task) {
-        ensureLoaded();
-        getScheduler().runAsync(task, Schedulers.getTrace(task));
-    }
-
-    public static void runDelayedAsync(@NotNull Runnable task, long delay, TimeUnit unit, ExecutorTrace trace) {
-        ensureLoaded();
-        getScheduler().runDelayedAsync(task, delay, unit, trace);
-    }
-
-    public static void runDelayedAsync(@NotNull Runnable task, long delay, @NotNull TimeUnit unit) {
-        ensureLoaded();
-        getScheduler().runDelayedAsync(task, delay, unit, Schedulers.getTrace(task));
-    }
-
-    public static void runRepeatingAsync(@NotNull Runnable task, long interval, @NotNull TimeUnit unit, @NotNull ExecutorTrace trace) {
-        ensureLoaded();
-        getScheduler().runRepeatingAsync(task, interval, unit, trace);
-    }
-
-    public static void runRepeatingAsync(@NotNull Runnable task, long interval, @NotNull TimeUnit unit) {
-        ensureLoaded();
-        getScheduler().runRepeatingAsync(task, interval, unit, Schedulers.getTrace(task));
-    }
-
-    public static ExecutorTrace getTrace(@NotNull Object function) {
-        return new ExecutorTrace(function.getClass(), Thread.currentThread().getStackTrace());
-    }
-
-    public static void ensureLoaded() {
-        if (getScheduler() == null) {
-            LOGGER.warn("No scheduler loaded, falling back to default single threaded scheduler");
-            setScheduler(SingleExecutorScheduler.create());
-        }
-    }
-
-    public static void loadDefaultScheduler() {
-
-    }
-
-    public static boolean isLoaded() {
-        return getScheduler() != null;
-    }
-
-    public static @Nullable Scheduler getScheduler() {
-        return scheduler;
-    }
-
-    public static void setScheduler(@NotNull Scheduler scheduler) {
-        Schedulers.scheduler = scheduler;
-    }
-
-}

futur-api/src/main/java/dev/tommyjs/futur/scheduler/SingleExecutorScheduler.java

@@ -3,7 +3,6 @@ package dev.tommyjs.futur.scheduler;
 import dev.tommyjs.futur.trace.ExecutorTrace;
 import org.jetbrains.annotations.NotNull;
 
-import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
 
@@ -11,23 +10,23 @@ public class SingleExecutorScheduler implements Scheduler {
 
     private final ScheduledExecutorService service;
 
-    protected SingleExecutorScheduler(ScheduledExecutorService service) {
+    public SingleExecutorScheduler(ScheduledExecutorService service) {
         this.service = service;
     }
 
     @Override
     public void runSync(@NotNull Runnable task, @NotNull ExecutorTrace trace) {
-        service.submit(wrapExceptions(task, trace));
+        service.submit(Scheduler.wrapExceptions(task, trace));
     }
 
     @Override
     public void runDelayedSync(@NotNull Runnable task, long delay, @NotNull TimeUnit unit, @NotNull ExecutorTrace trace) {
-        service.schedule(wrapExceptions(task, trace), delay, unit);
+        service.schedule(Scheduler.wrapExceptions(task, trace), delay, unit);
     }
 
     @Override
     public void runRepeatingSync(@NotNull Runnable task, long interval, @NotNull TimeUnit unit, @NotNull ExecutorTrace trace) {
-        service.scheduleAtFixedRate(wrapExceptions(task, trace), 0L, interval, unit);
+        service.scheduleAtFixedRate(Scheduler.wrapExceptions(task, trace), 0L, interval, unit);
     }
 
     @Override
@@ -45,8 +44,4 @@ public class SingleExecutorScheduler implements Scheduler {
         runRepeatingSync(task, interval, unit, trace);
     }
 
-    public static SingleExecutorScheduler create() {
-        return new SingleExecutorScheduler(Executors.newSingleThreadScheduledExecutor());
-    }
-
 }

futur-api/src/main/java/dev/tommyjs/futur/trace/TraceUtil.java

@@ -0,0 +1,11 @@
+package dev.tommyjs.futur.trace;
+
+import org.jetbrains.annotations.NotNull;
+
+public class TraceUtil {
+
+    public static ExecutorTrace getTrace(@NotNull Object function) {
+        return new ExecutorTrace(function.getClass(), Thread.currentThread().getStackTrace());
+    }
+
+}

futur-api/src/test/java/dev/tommyjs/test/Test.java

@@ -0,0 +1,35 @@
+package dev.tommyjs.test;
+
+import dev.tommyjs.futur.promise.PooledPromiseFactory;
+import dev.tommyjs.futur.promise.Promise;
+import dev.tommyjs.futur.promise.PromiseFactory;
+import dev.tommyjs.futur.scheduler.Scheduler;
+import dev.tommyjs.futur.scheduler.SingleExecutorScheduler;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+
+public class Test {
+
+    public static void main(String[] args) throws InterruptedException {
+        Scheduler scheduler = new SingleExecutorScheduler(Executors.newScheduledThreadPool(4));
+        Logger logger = LoggerFactory.getLogger(Test.class);
+        PromiseFactory factory = new PooledPromiseFactory(scheduler, logger);
+
+        Thread.sleep(2000);
+
+        Promise.start(factory)
+            .thenRunAsync(() -> {
+                System.out.println("HI");
+            })
+            .thenApplyDelayedAsync(_v -> {
+                return "ABC";
+            }, 1L, TimeUnit.SECONDS)
+            .thenConsumeSync(t -> {
+                System.out.println(t);
+            });
+    }
+
+}