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
17package com.google.common.util.concurrent;
18
19import static java.util.concurrent.TimeUnit.NANOSECONDS;
20
21import com.google.common.annotations.Beta;
22import com.google.common.base.Preconditions;
23
24import java.util.concurrent.BlockingQueue;
25import java.util.concurrent.CountDownLatch;
26import java.util.concurrent.ExecutionException;
27import java.util.concurrent.Future;
28import java.util.concurrent.TimeUnit;
29import java.util.concurrent.TimeoutException;
30
31/**
32 * Utilities for treating interruptible operations as uninterruptible.
33 * In all cases, if a thread is interrupted during such a call, the call
34 * continues to block until the result is available or the timeout elapses,
35 * and only then re-interrupts the thread.
36 *
37 * @author Anthony Zana
38 * @since 10.0
39 */
40@Beta
41public final class Uninterruptibles {
42
43  // Implementation Note: As of 3-7-11, the logic for each blocking/timeout
44  // methods is identical, save for method being invoked.
45
46  /**
47   * Invokes {@code latch.}{@link CountDownLatch#await() await()}
48   * uninterruptibly.
49   */
50  public static void awaitUninterruptibly(CountDownLatch latch) {
51    boolean interrupted = false;
52    try {
53      while (true) {
54        try {
55          latch.await();
56          return;
57        } catch (InterruptedException e) {
58          interrupted = true;
59        }
60      }
61    } finally {
62      if (interrupted) {
63        Thread.currentThread().interrupt();
64      }
65    }
66  }
67
68  /**
69   * Invokes
70   * {@code latch.}{@link CountDownLatch#await(long, TimeUnit)
71   * await(timeout, unit)} uninterruptibly.
72   */
73  public static boolean awaitUninterruptibly(CountDownLatch latch,
74      long timeout, TimeUnit unit) {
75    boolean interrupted = false;
76    try {
77      long remainingNanos = unit.toNanos(timeout);
78      long end = System.nanoTime() + remainingNanos;
79
80      while (true) {
81        try {
82          // CountDownLatch treats negative timeouts just like zero.
83          return latch.await(remainingNanos, NANOSECONDS);
84        } catch (InterruptedException e) {
85          interrupted = true;
86          remainingNanos = end - System.nanoTime();
87        }
88      }
89    } finally {
90      if (interrupted) {
91        Thread.currentThread().interrupt();
92      }
93    }
94  }
95
96  /**
97   * Invokes {@code toJoin.}{@link Thread#join() join()} uninterruptibly.
98   */
99  public static void joinUninterruptibly(Thread toJoin) {
100    boolean interrupted = false;
101    try {
102      while (true) {
103        try {
104          toJoin.join();
105          return;
106        } catch (InterruptedException e) {
107          interrupted = true;
108        }
109      }
110    } finally {
111      if (interrupted) {
112        Thread.currentThread().interrupt();
113      }
114    }
115  }
116
117  /**
118   * Invokes {@code future.}{@link Future#get() get()} uninterruptibly.
119   * To get uninterruptibility and remove checked exceptions, see
120   * {@link Futures#getUnchecked}.
121   *
122   * <p>If instead, you wish to treat {@link InterruptedException} uniformly
123   * with other exceptions, see {@link Futures#get(Future, Class) Futures.get}
124   * or {@link Futures#makeChecked}.
125   *
126   * @throws ExecutionException if the computation threw an exception
127   * @throws CancellationException if the computation was cancelled
128   */
129  public static <V> V getUninterruptibly(Future<V> future)
130      throws ExecutionException {
131    boolean interrupted = false;
132    try {
133      while (true) {
134        try {
135          return future.get();
136        } catch (InterruptedException e) {
137          interrupted = true;
138        }
139      }
140    } finally {
141      if (interrupted) {
142        Thread.currentThread().interrupt();
143      }
144    }
145  }
146
147  /**
148   * Invokes
149   * {@code future.}{@link Future#get(long, TimeUnit) get(timeout, unit)}
150   * uninterruptibly.
151   *
152   * <p>If instead, you wish to treat {@link InterruptedException} uniformly
153   * with other exceptions, see {@link Futures#get(Future, Class) Futures.get}
154   * or {@link Futures#makeChecked}.
155   *
156   * @throws ExecutionException if the computation threw an exception
157   * @throws CancellationException if the computation was cancelled
158   * @throws TimeoutException if the wait timed out
159   */
160  public static <V> V getUninterruptibly(
161      Future<V> future, long timeout,  TimeUnit unit)
162          throws ExecutionException, TimeoutException {
163    boolean interrupted = false;
164    try {
165      long remainingNanos = unit.toNanos(timeout);
166      long end = System.nanoTime() + remainingNanos;
167
168      while (true) {
169        try {
170          // Future treats negative timeouts just like zero.
171          return future.get(remainingNanos, NANOSECONDS);
172        } catch (InterruptedException e) {
173          interrupted = true;
174          remainingNanos = end - System.nanoTime();
175        }
176      }
177    } finally {
178      if (interrupted) {
179        Thread.currentThread().interrupt();
180      }
181    }
182  }
183
184  /**
185   * Invokes
186   * {@code unit.}{@link TimeUnit#timedJoin(Thread, long)
187   * timedJoin(toJoin, timeout)} uninterruptibly.
188   */
189  public static void joinUninterruptibly(Thread toJoin,
190      long timeout, TimeUnit unit) {
191    Preconditions.checkNotNull(toJoin);
192    boolean interrupted = false;
193    try {
194      long remainingNanos = unit.toNanos(timeout);
195      long end = System.nanoTime() + remainingNanos;
196      while (true) {
197        try {
198          // TimeUnit.timedJoin() treats negative timeouts just like zero.
199          NANOSECONDS.timedJoin(toJoin, remainingNanos);
200          return;
201        } catch (InterruptedException e) {
202          interrupted = true;
203          remainingNanos = end - System.nanoTime();
204        }
205      }
206    } finally {
207      if (interrupted) {
208        Thread.currentThread().interrupt();
209      }
210    }
211  }
212
213  /**
214   * Invokes {@code queue.}{@link BlockingQueue#take() take()} uninterruptibly.
215   */
216  public static <E> E takeUninterruptibly(BlockingQueue<E> queue) {
217    boolean interrupted = false;
218    try {
219      while (true) {
220        try {
221          return queue.take();
222        } catch (InterruptedException e) {
223          interrupted = true;
224        }
225      }
226    } finally {
227      if (interrupted) {
228        Thread.currentThread().interrupt();
229      }
230    }
231  }
232
233  /**
234   * Invokes {@code queue.}{@link BlockingQueue#put(Object) put(element)}
235   * uninterruptibly.
236   *
237   * @throws ClassCastException if the class of the specified element prevents
238   *     it from being added to the given queue
239   * @throws IllegalArgumentException if some property of the specified element
240   *     prevents it from being added to the given queue
241   */
242  public static <E> void putUninterruptibly(BlockingQueue<E> queue, E element) {
243    boolean interrupted = false;
244    try {
245      while (true) {
246        try {
247          queue.put(element);
248          return;
249        } catch (InterruptedException e) {
250          interrupted = true;
251        }
252      }
253    } finally {
254      if (interrupted) {
255        Thread.currentThread().interrupt();
256      }
257    }
258  }
259
260  // TODO(user): Support Sleeper somehow (wrapper or interface method)?
261  /**
262   * Invokes {@code unit.}{@link TimeUnit#sleep(long) sleep(sleepFor)}
263   * uninterruptibly.
264   */
265  public static void sleepUninterruptibly(long sleepFor, TimeUnit unit) {
266    boolean interrupted = false;
267    try {
268      long remainingNanos = unit.toNanos(sleepFor);
269      long end = System.nanoTime() + remainingNanos;
270      while (true) {
271        try {
272          // TimeUnit.sleep() treats negative timeouts just like zero.
273          NANOSECONDS.sleep(remainingNanos);
274          return;
275        } catch (InterruptedException e) {
276          interrupted = true;
277          remainingNanos = end - System.nanoTime();
278        }
279      }
280    } finally {
281      if (interrupted) {
282        Thread.currentThread().interrupt();
283      }
284    }
285  }
286
287  // TODO(user): Add support for waitUninterruptibly.
288
289  private Uninterruptibles() {}
290}
291