1 /* 2 * Copyright (C) 2011 The Guava Authors 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.google.common.util.concurrent; 18 19 import static com.google.common.base.Preconditions.checkNotNull; 20 21 import com.google.common.annotations.GwtCompatible; 22 import java.util.concurrent.ExecutionException; 23 import java.util.concurrent.Future; 24 import java.util.concurrent.TimeUnit; 25 import java.util.concurrent.TimeoutException; 26 27 /** 28 * A {@link Future} implementation which always throws directly from calls to {@code get()} (i.e. 29 * not wrapped in {@code ExecutionException}. For just a normal failure, use {@link 30 * SettableFuture}). 31 * 32 * <p>Useful for testing the behavior of Future utilities against odd futures. 33 * 34 * @author Anthony Zana 35 */ 36 @GwtCompatible 37 final class UncheckedThrowingFuture<V> extends AbstractFuture<V> { 38 throwingError(Error error)39 public static <V> ListenableFuture<V> throwingError(Error error) { 40 UncheckedThrowingFuture<V> future = new UncheckedThrowingFuture<V>(); 41 future.complete(checkNotNull(error)); 42 return future; 43 } 44 throwingRuntimeException(RuntimeException e)45 public static <V> ListenableFuture<V> throwingRuntimeException(RuntimeException e) { 46 UncheckedThrowingFuture<V> future = new UncheckedThrowingFuture<V>(); 47 future.complete(checkNotNull(e)); 48 return future; 49 } 50 incomplete()51 public static <V> UncheckedThrowingFuture<V> incomplete() { 52 return new UncheckedThrowingFuture<V>(); 53 } 54 complete(RuntimeException e)55 public void complete(RuntimeException e) { 56 if (!super.setException(new WrapperException(checkNotNull(e)))) { 57 throw new IllegalStateException("Future was already complete: " + this); 58 } 59 } 60 complete(Error e)61 public void complete(Error e) { 62 if (!super.setException(new WrapperException(checkNotNull(e)))) { 63 throw new IllegalStateException("Future was already complete: " + this); 64 } 65 } 66 67 private static final class WrapperException extends Exception { WrapperException(Throwable t)68 WrapperException(Throwable t) { 69 super(t); 70 } 71 } 72 rethrow(ExecutionException e)73 private static void rethrow(ExecutionException e) throws ExecutionException { 74 Throwable wrapper = e.getCause(); 75 if (wrapper instanceof WrapperException) { 76 Throwable cause = wrapper.getCause(); 77 if (cause instanceof RuntimeException) { 78 throw (RuntimeException) cause; 79 } else if (cause instanceof Error) { 80 throw (Error) cause; 81 } 82 } 83 throw e; 84 } 85 86 @Override get()87 public V get() throws ExecutionException, InterruptedException { 88 try { 89 super.get(); 90 } catch (ExecutionException e) { 91 rethrow(e); 92 } 93 throw new AssertionError("Unreachable"); 94 } 95 96 @Override get(long timeout, TimeUnit unit)97 public V get(long timeout, TimeUnit unit) 98 throws InterruptedException, ExecutionException, TimeoutException { 99 try { 100 super.get(timeout, unit); 101 } catch (ExecutionException e) { 102 rethrow(e); 103 } 104 throw new AssertionError("Unreachable"); 105 } 106 } 107