Multi await feature for intentional blocking

common/reactive/src/main/java/io/helidon/common/reactive/Awaitable.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2020 Oracle and/or its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.helidon.common.reactive;
+
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionException;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+
+/**
+ * Makes intentional blocking when waiting for {@link CompletableFuture} more convenient with {@link Awaitable#await()}
+ * and {@link Awaitable#await(long, java.util.concurrent.TimeUnit)} methods.
+ *
+ * @param <T> payload type
+ */
+public interface Awaitable<T> {
+
+    /**
+     * Returns a {@link java.util.concurrent.CompletableFuture} maintaining the same
+     * completion properties as this stage. If this stage is already a
+     * CompletableFuture, this method may return this stage itself.
+     * Otherwise, invocation of this method may be equivalent in
+     * effect to {@code thenApply(x -> x)}, but returning an instance
+     * of type {@code CompletableFuture}.
+     *
+     * @return the CompletableFuture
+     */
+    CompletableFuture<T> toCompletableFuture();
+
+    /**
+     * Block until {@link CompletableFuture} is completed, throws only unchecked exceptions.
+     *
+     * @return T payload type
+     * @throws java.util.concurrent.CancellationException if the computation was cancelled
+     * @throws java.util.concurrent.CompletionException   if this future completed
+     */
+    default T await() {
+        return this.toCompletableFuture().join();
+    }
+
+    /**
+     * Block until {@link CompletableFuture} is completed, throws only unchecked exceptions.
+     *
+     * @param timeout the maximum time to wait
+     * @param unit    the time unit of the timeout argument
+     * @return the result value
+     * @throws java.util.concurrent.CancellationException if this future was cancelled
+     * @throws java.util.concurrent.CompletionException   if this future completed exceptionally,
+     *                                                    was interrupted while waiting or the wait timed out
+     */
+    default T await(long timeout, TimeUnit unit) {
+        try {
+            return this.toCompletableFuture().get(timeout, unit);
+        } catch (ExecutionException e) {
+            throw new CompletionException(e.getCause());
+        } catch (InterruptedException | TimeoutException e) {
+            throw new CompletionException(e);
+        }
+    }
+}

common/reactive/src/main/java/io/helidon/common/reactive/CompletionAwaitable.java

@@ -0,0 +1,301 @@
+/*
+ * Copyright (c) 2020 Oracle and/or its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.helidon.common.reactive;
+
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionStage;
+import java.util.concurrent.Executor;
+import java.util.function.BiConsumer;
+import java.util.function.BiFunction;
+import java.util.function.Consumer;
+import java.util.function.Function;
+import java.util.function.Supplier;
+
+/**
+ * {@link CompletionStage} wrapper enriched with {@link io.helidon.common.reactive.Awaitable}.
+ *
+ * @param <T> payload type
+ */
+public class CompletionAwaitable<T> implements CompletionStage<T>, Awaitable<T> {
+
+    private Supplier<CompletionStage<T>> originalStage;
+
+    CompletionAwaitable(Supplier<CompletionStage<T>> originalStage) {
+        this.originalStage = originalStage;
+    }
+
+    CompletionAwaitable() {
+    }
+
+    void setOriginalStage(final Supplier<CompletionStage<T>> originalStage) {
+        this.originalStage = originalStage;
+    }
+
+    @Override
+    public <U> CompletionAwaitable<U> thenApply(final Function<? super T, ? extends U> fn) {
+        CompletionStage<U> completionStage = originalStage.get().thenApply(fn);
+        return new CompletionAwaitable<U>(() -> completionStage);
+    }
+
+    @Override
+    public <U> CompletionAwaitable<U> thenApplyAsync(final Function<? super T, ? extends U> fn) {
+        CompletionStage<U> completionStage = originalStage.get().thenApplyAsync(fn);
+        return new CompletionAwaitable<U>(() -> completionStage);
+    }
+
+    @Override
+    public <U> CompletionAwaitable<U> thenApplyAsync(final Function<? super T, ? extends U> fn, final Executor executor) {
+        CompletionStage<U> completionStage = originalStage.get().thenApplyAsync(fn, executor);
+        return new CompletionAwaitable<U>(() -> completionStage);
+    }
+
+    @Override
+    public CompletionAwaitable<Void> thenAccept(final Consumer<? super T> action) {
+        CompletionStage<Void> completionStage = originalStage.get().thenAccept(action);
+        return new CompletionAwaitable<Void>(() -> completionStage);
+
+    }
+
+    @Override
+    public CompletionAwaitable<Void> thenAcceptAsync(final Consumer<? super T> action) {
+        CompletionStage<Void> completionStage = originalStage.get().thenAcceptAsync(action);
+        return new CompletionAwaitable<Void>(() -> completionStage);
+    }
+
+    @Override
+    public CompletionAwaitable<Void> thenAcceptAsync(final Consumer<? super T> action, final Executor executor) {
+        CompletionStage<Void> completionStage = originalStage.get().thenAcceptAsync(action, executor);
+        return new CompletionAwaitable<Void>(() -> completionStage);
+    }
+
+    @Override
+    public CompletionAwaitable<Void> thenRun(final Runnable action) {
+        CompletionStage<Void> completionStage = originalStage.get().thenRun(action);
+        return new CompletionAwaitable<Void>(() -> completionStage);
+    }
+
+    @Override
+    public CompletionAwaitable<Void> thenRunAsync(final Runnable action) {
+        CompletionStage<Void> completionStage = originalStage.get().thenRunAsync(action);
+        return new CompletionAwaitable<Void>(() -> completionStage);
+    }
+
+    @Override
+    public CompletionAwaitable<Void> thenRunAsync(final Runnable action, final Executor executor) {
+        CompletionStage<Void> completionStage = originalStage.get().thenRunAsync(action, executor);
+        return new CompletionAwaitable<Void>(() -> completionStage);
+    }
+
+    @Override
+    public <U, V> CompletionAwaitable<V> thenCombine(final CompletionStage<? extends U> other,
+                                                     final BiFunction<? super T, ? super U, ? extends V> fn) {
+        CompletionStage<V> completionStage = originalStage.get().thenCombine(other, fn);
+        return new CompletionAwaitable<V>(() -> completionStage);
+    }
+
+    @Override
+    public <U, V> CompletionAwaitable<V> thenCombineAsync(final CompletionStage<? extends U> other,
+                                                          final BiFunction<? super T, ? super U, ? extends V> fn) {
+        CompletionStage<V> completionStage = originalStage.get().thenCombineAsync(other, fn);
+        return new CompletionAwaitable<V>(() -> completionStage);
+    }
+
+    @Override
+    public <U, V> CompletionAwaitable<V> thenCombineAsync(final CompletionStage<? extends U> other,
+                                                          final BiFunction<? super T, ? super U, ? extends V> fn,
+                                                          final Executor executor) {
+        CompletionStage<V> completionStage = originalStage.get().thenCombineAsync(other, fn, executor);
+        return new CompletionAwaitable<V>(() -> completionStage);
+    }
+
+    @Override
+    public <U> CompletionAwaitable<Void> thenAcceptBoth(final CompletionStage<? extends U> other,
+                                                        final BiConsumer<? super T, ? super U> action) {
+        CompletionStage<Void> completionStage = originalStage.get().thenAcceptBoth(other, action);
+        return new CompletionAwaitable<Void>(() -> completionStage);
+    }
+
+    @Override
+    public <U> CompletionAwaitable<Void> thenAcceptBothAsync(final CompletionStage<? extends U> other,
+                                                             final BiConsumer<? super T, ? super U> action) {
+        CompletionStage<Void> completionStage = originalStage.get().thenAcceptBothAsync(other, action);
+        return new CompletionAwaitable<Void>(() -> completionStage);
+    }
+
+    @Override
+    public <U> CompletionAwaitable<Void> thenAcceptBothAsync(final CompletionStage<? extends U> other,
+                                                             final BiConsumer<? super T, ? super U> action,
+                                                             final Executor executor) {
+        CompletionStage<Void> completionStage = originalStage.get().thenAcceptBothAsync(other, action, executor);
+        return new CompletionAwaitable<Void>(() -> completionStage);
+    }
+
+    @Override
+    public CompletionAwaitable<Void> runAfterBoth(final CompletionStage<?> other,
+                                                  final Runnable action) {
+        CompletionStage<Void> completionStage = originalStage.get().runAfterBoth(other, action);
+        return new CompletionAwaitable<Void>(() -> completionStage);
+    }
+
+    @Override
+    public CompletionAwaitable<Void> runAfterBothAsync(final CompletionStage<?> other,
+                                                       final Runnable action) {
+        CompletionStage<Void> completionStage = originalStage.get().runAfterBothAsync(other, action);
+        return new CompletionAwaitable<Void>(() -> completionStage);
+    }
+
+    @Override
+    public CompletionAwaitable<Void> runAfterBothAsync(final CompletionStage<?> other,
+                                                       final Runnable action,
+                                                       final Executor executor) {
+        CompletionStage<Void> completionStage = originalStage.get().runAfterBothAsync(other, action, executor);
+        return new CompletionAwaitable<Void>(() -> completionStage);
+    }
+
+    @Override
+    public <U> CompletionAwaitable<U> applyToEither(final CompletionStage<? extends T> other,
+                                                    final Function<? super T, U> fn) {
+        CompletionStage<U> completionStage = originalStage.get().applyToEither(other, fn);
+        return new CompletionAwaitable<U>(() -> completionStage);
+    }
+
+    @Override
+    public <U> CompletionAwaitable<U> applyToEitherAsync(final CompletionStage<? extends T> other,
+                                                         final Function<? super T, U> fn) {
+        CompletionStage<U> completionStage = originalStage.get().applyToEitherAsync(other, fn);
+        return new CompletionAwaitable<U>(() -> completionStage);
+    }
+
+    @Override
+    public <U> CompletionAwaitable<U> applyToEitherAsync(final CompletionStage<? extends T> other,
+                                                         final Function<? super T, U> fn,
+                                                         final Executor executor) {
+        CompletionStage<U> completionStage = originalStage.get().applyToEitherAsync(other, fn, executor);
+        return new CompletionAwaitable<U>(() -> completionStage);
+    }
+
+    @Override
+    public CompletionAwaitable<Void> acceptEither(final CompletionStage<? extends T> other,
+                                                  final Consumer<? super T> action) {
+        CompletionStage<Void> completionStage = originalStage.get().acceptEither(other, action);
+        return new CompletionAwaitable<Void>(() -> completionStage);
+    }
+
+    @Override
+    public CompletionAwaitable<Void> acceptEitherAsync(final CompletionStage<? extends T> other,
+                                                       final Consumer<? super T> action) {
+        CompletionStage<Void> completionStage = originalStage.get().acceptEitherAsync(other, action);
+        return new CompletionAwaitable<Void>(() -> completionStage);
+    }
+
+    @Override
+    public CompletionAwaitable<Void> acceptEitherAsync(final CompletionStage<? extends T> other,
+                                                       final Consumer<? super T> action,
+                                                       final Executor executor) {
+        CompletionStage<Void> completionStage = originalStage.get().acceptEitherAsync(other, action, executor);
+        return new CompletionAwaitable<Void>(() -> completionStage);
+    }
+
+    @Override
+    public CompletionAwaitable<Void> runAfterEither(final CompletionStage<?> other,
+                                                    final Runnable action) {
+        CompletionStage<Void> completionStage = originalStage.get().runAfterEither(other, action);
+        return new CompletionAwaitable<Void>(() -> completionStage);
+    }
+
+    @Override
+    public CompletionAwaitable<Void> runAfterEitherAsync(final CompletionStage<?> other,
+                                                         final Runnable action) {
+        CompletionStage<Void> completionStage = originalStage.get().runAfterEitherAsync(other, action);
+        return new CompletionAwaitable<Void>(() -> completionStage);
+    }
+
+    @Override
+    public CompletionAwaitable<Void> runAfterEitherAsync(final CompletionStage<?> other,
+                                                         final Runnable action, final Executor executor) {
+        CompletionStage<Void> completionStage = originalStage.get().runAfterEitherAsync(other, action, executor);
+        return new CompletionAwaitable<Void>(() -> completionStage);
+    }
+
+    @Override
+    public <U> CompletionAwaitable<U> thenCompose(final Function<? super T, ? extends CompletionStage<U>> fn) {
+        CompletionStage<U> completionStage = originalStage.get().thenCompose(fn);
+        return new CompletionAwaitable<U>(() -> completionStage);
+    }
+
+    @Override
+    public <U> CompletionAwaitable<U> thenComposeAsync(final Function<? super T, ? extends CompletionStage<U>> fn) {
+        CompletionStage<U> completionStage = originalStage.get().thenComposeAsync(fn);
+        return new CompletionAwaitable<U>(() -> completionStage);
+    }
+
+    @Override
+    public <U> CompletionAwaitable<U> thenComposeAsync(final Function<? super T, ? extends CompletionStage<U>> fn,
+                                                       final Executor executor) {
+        CompletionStage<U> completionStage = originalStage.get().thenComposeAsync(fn, executor);
+        return new CompletionAwaitable<U>(() -> completionStage);
+    }
+
+    @Override
+    public <U> CompletionAwaitable<U> handle(final BiFunction<? super T, Throwable, ? extends U> fn) {
+        CompletionStage<U> completionStage = originalStage.get().handle(fn);
+        return new CompletionAwaitable<U>(() -> completionStage);
+    }
+
+    @Override
+    public <U> CompletionAwaitable<U> handleAsync(final BiFunction<? super T, Throwable, ? extends U> fn) {
+        CompletionStage<U> completionStage = originalStage.get().handleAsync(fn);
+        return new CompletionAwaitable<U>(() -> completionStage);
+    }
+
+    @Override
+    public <U> CompletionAwaitable<U> handleAsync(final BiFunction<? super T, Throwable, ? extends U> fn,
+                                                  final Executor executor) {
+        CompletionStage<U> completionStage = originalStage.get().handleAsync(fn, executor);
+        return new CompletionAwaitable<U>(() -> completionStage);
+    }
+
+    @Override
+    public CompletionAwaitable<T> whenComplete(final BiConsumer<? super T, ? super Throwable> action) {
+        CompletionStage<T> completionStage = originalStage.get().whenComplete(action);
+        return new CompletionAwaitable<T>(() -> completionStage);
+    }
+
+    @Override
+    public CompletionAwaitable<T> whenCompleteAsync(final BiConsumer<? super T, ? super Throwable> action) {
+        CompletionStage<T> completionStage = originalStage.get().whenCompleteAsync(action);
+        return new CompletionAwaitable<T>(() -> completionStage);
+    }
+
+    @Override
+    public CompletionAwaitable<T> whenCompleteAsync(final BiConsumer<? super T, ? super Throwable> action,
+                                                    final Executor executor) {
+        CompletionStage<T> completionStage = originalStage.get().whenCompleteAsync(action, executor);
+        return new CompletionAwaitable<T>(() -> completionStage);
+    }
+
+    @Override
+    public CompletionAwaitable<T> exceptionally(final Function<Throwable, ? extends T> fn) {
+        CompletionStage<T> completionStage = originalStage.get().exceptionally(fn);
+        return new CompletionAwaitable<T>(() -> completionStage);
+    }
+
+    @Override
+    public CompletableFuture<T> toCompletableFuture() {
+        return originalStage.get().toCompletableFuture();
+    }
+}