| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 org.apache.cassandra.distributed.shared; |
| |
| import java.util.concurrent.CompletableFuture; |
| import java.util.concurrent.ExecutionException; |
| import java.util.concurrent.Future; |
| import java.util.concurrent.TimeUnit; |
| import java.util.concurrent.TimeoutException; |
| import java.util.function.Function; |
| |
| public final class FutureUtils { |
| private FutureUtils() { } |
| |
| public static <T> T waitOn(Future<T> f) |
| { |
| try |
| { |
| return f.get(); |
| } |
| catch (InterruptedException e) |
| { |
| Thread.currentThread().interrupt(); |
| throw new RuntimeException(e); |
| } |
| catch (ExecutionException e) |
| { |
| Throwable cause = e.getCause(); |
| if (cause instanceof Error) throw (Error) cause; |
| if (cause instanceof RuntimeException) throw (RuntimeException) cause; |
| throw new RuntimeException(cause); |
| } |
| } |
| |
| public static <A, B> Future<B> map(Future<A> future, Function<? super A, ? extends B> fn) { |
| if (future == null) throw new NullPointerException("Future is null"); |
| if (fn == null) throw new NullPointerException("Function is null"); |
| |
| if (future instanceof CompletableFuture) { |
| return ((CompletableFuture<A>) future).thenApply(fn); |
| } |
| return new MapFuture<>(future, fn); |
| } |
| |
| private static final class MapFuture<A, B> implements Future<B> |
| { |
| private final Future<A> parent; |
| private final Function<? super A, ? extends B> fn; |
| |
| private MapFuture(Future<A> parent, Function<? super A, ? extends B> fn) { |
| this.parent = parent; |
| this.fn = fn; |
| } |
| |
| @Override |
| public boolean cancel(boolean mayInterruptIfRunning) { |
| return parent.cancel(mayInterruptIfRunning); |
| } |
| |
| @Override |
| public boolean isCancelled() { |
| return parent.isCancelled(); |
| } |
| |
| @Override |
| public boolean isDone() { |
| return parent.isDone(); |
| } |
| |
| @Override |
| public B get() throws InterruptedException, ExecutionException { |
| return fn.apply(parent.get()); |
| } |
| |
| @Override |
| public B get(long timeout, TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException { |
| return fn.apply(parent.get(timeout, unit)); |
| } |
| } |
| } |