Initial commit

futur-api/.gitignore

@@ -0,0 +1,42 @@
+.gradle
+build/
+!gradle/wrapper/gradle-wrapper.jar
+!**/src/main/**/build/
+!**/src/test/**/build/
+
+### IntelliJ IDEA ###
+.idea/modules.xml
+.idea/jarRepositories.xml
+.idea/compiler.xml
+.idea/libraries/
+*.iws
+*.iml
+*.ipr
+out/
+!**/src/main/**/out/
+!**/src/test/**/out/
+
+### Eclipse ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+bin/
+!**/src/main/**/bin/
+!**/src/test/**/bin/
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+
+### VS Code ###
+.vscode/
+
+### Mac OS ###
+.DS_Store

futur-api/build.gradle.kts

@@ -0,0 +1,34 @@
+import com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar
+
+plugins {
+    id("java")
+    id("com.github.johnrengelman.shadow") version "7.1.2"
+}
+
+group = "dev.tommyjs"
+version = "1.0.0"
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation("org.jetbrains:annotations:24.1.0")
+    implementation("org.slf4j:slf4j-api:2.0.9")
+    testImplementation(platform("org.junit:junit-bom:5.9.1"))
+    testImplementation("org.junit.jupiter:junit-jupiter")
+}
+
+tasks {
+    build {
+        dependsOn(shadowJar)
+    }
+
+    withType<ShadowJar> {
+        exclude("META-INF/**")
+    }
+}
+
+tasks.test {
+    useJUnitPlatform()
+}

futur-api/src/main/java/dev/tommyjs/futur/function/ExceptionalConsumer.java

@@ -0,0 +1,7 @@
+package dev.tommyjs.futur.function;
+
+public interface ExceptionalConsumer<T> {
+
+    void accept(T value) throws Exception;
+
+}

futur-api/src/main/java/dev/tommyjs/futur/function/ExceptionalFunction.java

@@ -0,0 +1,7 @@
+package dev.tommyjs.futur.function;
+
+public interface ExceptionalFunction<K, V> {
+
+    V apply(K value) throws Exception;
+
+}

futur-api/src/main/java/dev/tommyjs/futur/function/ExceptionalRunnable.java

@@ -0,0 +1,7 @@
+package dev.tommyjs.futur.function;
+
+public interface ExceptionalRunnable {
+
+    void run() throws Exception;
+
+}

futur-api/src/main/java/dev/tommyjs/futur/function/ExceptionalSupplier.java

@@ -0,0 +1,7 @@
+package dev.tommyjs.futur.function;
+
+public interface ExceptionalSupplier<T> {
+
+    T get() throws Exception;
+
+}

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

@@ -0,0 +1,404 @@
+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.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> {
+
+    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();
+    }
+
+    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);
+    }
+
+    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();
+    }
+
+    public @NotNull Promise<Void> thenRunSync(@NotNull ExceptionalRunnable task) {
+        return thenApplySync(result -> {
+            task.run();
+            return null;
+        }, Schedulers.getTrace(task));
+    }
+
+    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));
+    }
+
+    public @NotNull Promise<Void> thenAcceptSync(@NotNull ExceptionalConsumer<T> task) {
+        return thenApplySync(result -> {
+            task.accept(result);
+            return null;
+        }, Schedulers.getTrace(task));
+    }
+
+    public @NotNull Promise<Void> thenAcceptDelayedSync(@NotNull ExceptionalConsumer<T> task, long delay, @NotNull TimeUnit unit) {
+        return thenApplyDelayedSync(result -> {
+            task.accept(result);
+            return null;
+        }, delay, unit, Schedulers.getTrace(task));
+    }
+
+    public <V> @NotNull Promise<V> thenSupplySync(@NotNull ExceptionalSupplier<V> task) {
+        return thenApplySync(result -> task.get(), Schedulers.getTrace(task));
+    }
+
+    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));
+    }
+
+    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;
+            }
+
+            Runnable runnable = createRunnable(ctx, promise, task);
+            Schedulers.runSync(runnable, trace);
+        });
+
+        return promise;
+    }
+
+    public <V> @NotNull Promise<V> thenApplySync(@NotNull ExceptionalFunction<T, V> task) {
+        return thenApplySync(task, Schedulers.getTrace(task));
+    }
+
+    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;
+            }
+
+            Runnable runnable = createRunnable(ctx, promise, task);
+            Schedulers.runDelayedSync(runnable, delay, unit, trace);
+        });
+
+        return promise;
+    }
+
+    public <V> @NotNull Promise<V> thenApplyDelayedSync(@NotNull ExceptionalFunction<T, V> task, long delay, @NotNull TimeUnit unit) {
+        return thenApplyDelayedSync(task, delay, unit, Schedulers.getTrace(task));
+    }
+
+    public <V> @NotNull Promise<V> thenComposeSync(@NotNull ExceptionalFunction<T, @NotNull Promise<V>> task) {
+        Promise<V> promise = new Promise<>();
+        thenApplySync(task, Schedulers.getTrace(task)).thenAcceptAsync(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;
+    }
+
+    public @NotNull Promise<Void> thenRunAsync(@NotNull ExceptionalRunnable task) {
+        return thenApplyAsync(result -> {
+            task.run();
+            return null;
+        }, Schedulers.getTrace(task));
+    }
+
+    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));
+    }
+
+    public @NotNull Promise<Void> thenAcceptAsync(@NotNull ExceptionalConsumer<T> task) {
+        return thenApplyAsync(result -> {
+            task.accept(result);
+            return null;
+        }, Schedulers.getTrace(task));
+    }
+
+    public @NotNull Promise<Void> thenAcceptDelayedAsync(@NotNull ExceptionalConsumer<T> task, long delay, @NotNull TimeUnit unit) {
+        return thenApplyDelayedAsync(result -> {
+            task.accept(result);
+            return null;
+        }, delay, unit, Schedulers.getTrace(task));
+    }
+
+    public <V> @NotNull Promise<V> thenSupplyAsync(@NotNull ExceptionalSupplier<V> task) {
+        return thenApplyAsync(result -> task.get(), Schedulers.getTrace(task));
+    }
+
+    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));
+    }
+
+    public @NotNull Promise<T> thenPopulateReference(@NotNull AtomicReference<T> reference) {
+        return thenApplyAsync((result) -> {
+            reference.set(result);
+            return result;
+        });
+    }
+
+    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();
+        });
+
+        return promise;
+    }
+
+    public <V> @NotNull Promise<V> thenApplyAsync(@NotNull ExceptionalFunction<T, V> task) {
+        return thenApplyAsync(task, Schedulers.getTrace(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);
+        });
+
+        return promise;
+    }
+
+    public <V> @NotNull Promise<V> thenApplyDelayedAsync(@NotNull ExceptionalFunction<T, V> task, long delay, @NotNull TimeUnit unit) {
+        return thenApplyDelayedAsync(task, delay, unit, Schedulers.getTrace(task));
+    }
+
+    public <V> @NotNull Promise<V> thenCompose(@NotNull ExceptionalFunction<T, Promise<V>> task) {
+        return this.thenComposeAsync(task);
+    }
+
+    public <V> @NotNull Promise<V> thenComposeAsync(@NotNull ExceptionalFunction<T, Promise<V>> task) {
+        Promise<V> promise = new Promise<>();
+        thenApplyAsync(task, Schedulers.getTrace(task)).thenAcceptAsync(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);
+            }
+        };
+    }
+
+    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;
+    }
+
+}

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

@@ -0,0 +1,47 @@
+package dev.tommyjs.futur.promise;
+
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+public class PromiseCompletion<T> {
+
+    private @Nullable T result;
+    private @Nullable Throwable exception;
+    private boolean active;
+
+    public PromiseCompletion(@Nullable T result) {
+        this.result = result;
+        this.active = true;
+    }
+
+    public PromiseCompletion(@NotNull Throwable exception) {
+        this.exception = exception;
+        this.active = true;
+    }
+
+    public PromiseCompletion() {
+        this.result = null;
+        this.active = true;
+    }
+
+    public void markHandled() {
+        this.active = false;
+    }
+
+    public boolean isActive() {
+        return active;
+    }
+
+    public boolean isError() {
+        return getException() != null;
+    }
+
+    public @Nullable T getResult() {
+        return result;
+    }
+
+    public @Nullable Throwable getException() {
+        return exception;
+    }
+
+}

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

@@ -0,0 +1,9 @@
+package dev.tommyjs.futur.promise;
+
+import org.jetbrains.annotations.NotNull;
+
+public interface PromiseListener<T> {
+
+    void handle(@NotNull PromiseCompletion<T> ctx);
+
+}

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

@@ -0,0 +1,173 @@
+package dev.tommyjs.futur.promise;
+
+import dev.tommyjs.futur.function.ExceptionalFunction;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.*;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.locks.ReentrantLock;
+import java.util.function.BiConsumer;
+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<>();
+        p1.addListener(ctx -> {
+            if (ctx.isError()) {
+                //noinspection ConstantConditions
+                promise.completeExceptionally(ctx.getException());
+                return;
+            }
+
+            p2.addListener(ctx1 -> {
+                if (ctx1.isError()) {
+                    //noinspection ConstantConditions
+                    promise.completeExceptionally(ctx1.getException());
+                    return;
+                }
+
+                Map.Entry<K, V> result = new AbstractMap.SimpleEntry<>(ctx.getResult(), ctx1.getResult());
+                promise.complete(result);
+            });
+        });
+
+        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);
+
+        ReentrantLock lock = new ReentrantLock();
+
+        Promise<Map<K, V>> promise = new Promise<>();
+        for (Map.Entry<K, Promise<V>> entry : promises.entrySet()) {
+            entry.getValue().addListener((ctx) -> {
+                lock.lock();
+
+                try {
+                    if (ctx.isError()) {
+                        if (exceptionHandler == null) {
+                            //noinspection ConstantConditions
+                            promise.completeExceptionally(ctx.getException());
+                        } else {
+                            exceptionHandler.accept(entry.getKey(), ctx.getException());
+                            map.put(entry.getKey(), null);
+                        }
+                    } else {
+                        map.put(entry.getKey(), ctx.getResult());
+                    }
+                    if (map.size() == promises.size()) promise.complete(map);
+                } finally {
+                    lock.unlock();
+                }
+            });
+        }
+        return promise.timeout(timeout);
+    }
+
+    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) -> {});
+    }
+
+    public static <K, V> @NotNull Promise<Map<K, V>> combine(@NotNull Map<K, Promise<V>> promises, long timeout) {
+        return combine(promises, timeout, true);
+    }
+
+    public static <K, V> @NotNull Promise<Map<K, V>> combine(@NotNull Map<K, Promise<V>> promises) {
+        return combine(promises, 1500L, true);
+    }
+
+    public static <V> @NotNull Promise<List<V>> combine(@NotNull List<Promise<V>> promises, long timeout, boolean strict) {
+        AtomicInteger index = new AtomicInteger();
+        return combine(
+            promises.stream()
+                .collect(Collectors.toMap(s -> index.getAndIncrement(), v -> v)),
+            timeout,
+            strict
+        ).thenApplySync(v ->
+            v.entrySet().stream()
+                .sorted(Map.Entry.comparingByKey())
+                .map(Map.Entry::getValue)
+                .collect(Collectors.toList())
+        );
+    }
+
+    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) {
+        return combine(promises, 1500L, true);
+    }
+
+    public static @NotNull Promise<Void> all(@NotNull List<Promise<?>> promises) {
+        if (promises.isEmpty()) return Promise.start();
+
+        Promise<Void> promise = new Promise<>();
+        for (Promise<?> p : promises) {
+            p.addListener((ctx) -> {
+                if (ctx.isError()) {
+                    //noinspection ConstantConditions
+                    promise.completeExceptionally(ctx.getException());
+                } else if (promises.stream().allMatch(Promise::isCompleted)) {
+                    promise.complete(null);
+                }
+            });
+        }
+        return promise;
+    }
+
+    public static @NotNull Promise<Void> all(@NotNull Promise<?>... promises) {
+        return all(Arrays.asList(promises));
+    }
+
+    public static <K, V> @NotNull Promise<Map<K, V>> combine(@NotNull Collection<K> keys, @NotNull ExceptionalFunction<K, V> mapper, long timeout, boolean strict) {
+        Map<K, Promise<V>> promises = new HashMap<>();
+        for (K key : keys) {
+            Promise<V> promise = Promise.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) {
+        return combine(keys, mapper, timeout, true);
+    }
+
+    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);
+    }
+
+    public static @NotNull Promise<Void> erase(@NotNull Promise<?> p) {
+        Promise<Void> promise = new Promise<>();
+        p.addListener(ctx -> {
+            if (ctx.isError()) {
+                //noinspection ConstantConditions
+                promise.completeExceptionally(ctx.getException());
+            } else {
+                promise.complete(null);
+            }
+        });
+
+        return promise;
+    }
+
+    public static <T> @NotNull Promise<T> wrap(@NotNull CompletableFuture<T> future) {
+        Promise<T> promise = new Promise<>();
+        future.whenComplete((result, e) -> {
+            if (e != null) {
+                promise.completeExceptionally(e);
+            } else {
+                promise.complete(result);
+            }
+        });
+
+        return promise;
+    }
+
+}

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

@@ -0,0 +1,37 @@
+package dev.tommyjs.futur.scheduler;
+
+import dev.tommyjs.futur.trace.ExecutorTrace;
+import org.jetbrains.annotations.NotNull;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.concurrent.TimeUnit;
+
+public interface Scheduler {
+
+    Logger LOGGER = LoggerFactory.getLogger(Scheduler.class);
+
+    void runSync(@NotNull Runnable task, @NotNull ExecutorTrace trace);
+
+    void runDelayedSync(@NotNull Runnable task, long delay, @NotNull TimeUnit unit, @NotNull ExecutorTrace trace);
+
+    void runRepeatingSync(@NotNull Runnable task, long interval, @NotNull TimeUnit unit, @NotNull ExecutorTrace trace);
+
+    void runAsync(@NotNull Runnable task, @NotNull ExecutorTrace trace);
+
+    void runDelayedAsync(@NotNull Runnable task, long delay, @NotNull TimeUnit unit, @NotNull ExecutorTrace trace);
+
+    void runRepeatingAsync(@NotNull Runnable task, long interval, @NotNull TimeUnit unit, @NotNull ExecutorTrace trace);
+
+    default @NotNull Runnable wrapExceptions(@NotNull Runnable task, @NotNull ExecutorTrace trace) {
+        return () -> {
+            try {
+                task.run();
+            } catch (Exception e) {
+                LOGGER.error("Exception in scheduled task: {}", e.getClass().getName());
+                LOGGER.error(trace.toString());
+            }
+        };
+    }
+
+}

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

@@ -0,0 +1,105 @@
+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

@@ -0,0 +1,52 @@
+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;
+
+public class SingleExecutorScheduler implements Scheduler {
+
+    private final ScheduledExecutorService service;
+
+    protected SingleExecutorScheduler(ScheduledExecutorService service) {
+        this.service = service;
+    }
+
+    @Override
+    public void runSync(@NotNull Runnable task, @NotNull ExecutorTrace trace) {
+        service.submit(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);
+    }
+
+    @Override
+    public void runRepeatingSync(@NotNull Runnable task, long interval, @NotNull TimeUnit unit, @NotNull ExecutorTrace trace) {
+        service.scheduleAtFixedRate(wrapExceptions(task, trace), 0L, interval, unit);
+    }
+
+    @Override
+    public void runAsync(@NotNull Runnable task, @NotNull ExecutorTrace trace) {
+        runSync(task, trace);
+    }
+
+    @Override
+    public void runDelayedAsync(@NotNull Runnable task, long delay, @NotNull TimeUnit unit, @NotNull ExecutorTrace trace) {
+        runDelayedSync(task, delay, unit, trace);
+    }
+
+    @Override
+    public void runRepeatingAsync(@NotNull Runnable task, long interval, @NotNull TimeUnit unit, @NotNull ExecutorTrace trace) {
+        runRepeatingSync(task, interval, unit, trace);
+    }
+
+    public static SingleExecutorScheduler create() {
+        return new SingleExecutorScheduler(Executors.newSingleThreadScheduledExecutor());
+    }
+
+}

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

@@ -0,0 +1,31 @@
+package dev.tommyjs.futur.trace;
+
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Arrays;
+import java.util.stream.Collectors;
+
+public class ExecutorTrace {
+
+    private final @NotNull Class<?> clazz;
+    private final @NotNull StackTraceElement[] trace;
+
+    public ExecutorTrace(@NotNull Class<?> clazz, @NotNull StackTraceElement[] trace) {
+        this.clazz = clazz;
+        this.trace = trace;
+    }
+
+    public @NotNull Class<?> getClazz() {
+        return clazz;
+    }
+
+    public @NotNull StackTraceElement[] getTrace() {
+        return trace;
+    }
+
+    @Override
+    public String toString() {
+        return Arrays.stream(trace).map(StackTraceElement::toString).collect(Collectors.joining("\n"));
+    }
+
+}