1 /* 2 * Copyright (C) 2018 The Guava Authors 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except 5 * in compliance with the License. You may obtain a copy of the License at 6 * 7 * http://www.apache.org/licenses/LICENSE-2.0 8 * 9 * Unless required by applicable law or agreed to in writing, software distributed under the License 10 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express 11 * or implied. See the License for the specific language governing permissions and limitations under 12 * the License. 13 */ 14 15 package com.google.common.util.concurrent.internal; 16 17 /** 18 * Static utilities for {@link InternalFutureFailureAccess}. Most users will never need to use this 19 * class. 20 * 21 * <p>This class is GWT-compatible. 22 * 23 * @since {@code com.google.guava:failureaccess:1.0}, which was added as a dependency of Guava in 24 * Guava 27.0 25 */ 26 public final class InternalFutures { 27 /** 28 * Usually returns {@code null} but, if the given {@code Future} has failed, may <i>optionally</i> 29 * return the cause of the failure. "Failure" means specifically "completed with an exception"; it 30 * does not include "was cancelled." To be explicit: If this method returns a non-null value, 31 * then: 32 * 33 * <ul> 34 * <li>{@code isDone()} must return {@code true} 35 * <li>{@code isCancelled()} must return {@code false} 36 * <li>{@code get()} must not block, and it must throw an {@code ExecutionException} with the 37 * return value of this method as its cause 38 * </ul> 39 */ tryInternalFastPathGetFailure(InternalFutureFailureAccess future)40 public static Throwable tryInternalFastPathGetFailure(InternalFutureFailureAccess future) { 41 return future.tryInternalFastPathGetFailure(); 42 } 43 InternalFutures()44 private InternalFutures() {} 45 } 46