001/*
002 * Copyright (C) 2006 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
005 * in compliance with the License. You may obtain a copy of the License at
006 *
007 * http://www.apache.org/licenses/LICENSE-2.0
008 *
009 * Unless required by applicable law or agreed to in writing, software distributed under the License
010 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
011 * or implied. See the License for the specific language governing permissions and limitations under
012 * the License.
013 */
014
015package com.google.common.util.concurrent;
016
017import static com.google.common.base.Preconditions.checkArgument;
018import static com.google.common.base.Preconditions.checkNotNull;
019
020import com.google.common.annotations.Beta;
021import com.google.common.annotations.GwtIncompatible;
022import com.google.common.collect.ObjectArrays;
023import com.google.common.collect.Sets;
024import com.google.errorprone.annotations.CanIgnoreReturnValue;
025import java.lang.reflect.InvocationHandler;
026import java.lang.reflect.InvocationTargetException;
027import java.lang.reflect.Method;
028import java.lang.reflect.Proxy;
029import java.util.Set;
030import java.util.concurrent.Callable;
031import java.util.concurrent.ExecutionException;
032import java.util.concurrent.ExecutorService;
033import java.util.concurrent.Executors;
034import java.util.concurrent.Future;
035import java.util.concurrent.TimeUnit;
036import java.util.concurrent.TimeoutException;
037import javax.annotation.CheckForNull;
038import org.checkerframework.checker.nullness.qual.Nullable;
039
040/**
041 * A TimeLimiter that runs method calls in the background using an {@link ExecutorService}. If the
042 * time limit expires for a given method call, the thread running the call will be interrupted.
043 *
044 * @author Kevin Bourrillion
045 * @author Jens Nyman
046 * @since 1.0
047 */
048@Beta
049@GwtIncompatible
050@ElementTypesAreNonnullByDefault
051public final class SimpleTimeLimiter implements TimeLimiter {
052
053  private final ExecutorService executor;
054
055  private SimpleTimeLimiter(ExecutorService executor) {
056    this.executor = checkNotNull(executor);
057  }
058
059  /**
060   * Creates a TimeLimiter instance using the given executor service to execute method calls.
061   *
062   * <p><b>Warning:</b> using a bounded executor may be counterproductive! If the thread pool fills
063   * up, any time callers spend waiting for a thread may count toward their time limit, and in this
064   * case the call may even time out before the target method is ever invoked.
065   *
066   * @param executor the ExecutorService that will execute the method calls on the target objects;
067   *     for example, a {@link Executors#newCachedThreadPool()}.
068   * @since 22.0
069   */
070  public static SimpleTimeLimiter create(ExecutorService executor) {
071    return new SimpleTimeLimiter(executor);
072  }
073
074  @Override
075  public <T> T newProxy(
076      T target, Class<T> interfaceType, long timeoutDuration, TimeUnit timeoutUnit) {
077    checkNotNull(target);
078    checkNotNull(interfaceType);
079    checkNotNull(timeoutUnit);
080    checkPositiveTimeout(timeoutDuration);
081    checkArgument(interfaceType.isInterface(), "interfaceType must be an interface type");
082
083    Set<Method> interruptibleMethods = findInterruptibleMethods(interfaceType);
084
085    InvocationHandler handler =
086        new InvocationHandler() {
087          @Override
088          @CheckForNull
089          public Object invoke(Object obj, Method method, @CheckForNull @Nullable Object[] args)
090              throws Throwable {
091            Callable<@Nullable Object> callable =
092                () -> {
093                  try {
094                    return method.invoke(target, args);
095                  } catch (InvocationTargetException e) {
096                    throw throwCause(e, false /* combineStackTraces */);
097                  }
098                };
099            return callWithTimeout(
100                callable, timeoutDuration, timeoutUnit, interruptibleMethods.contains(method));
101          }
102        };
103    return newProxy(interfaceType, handler);
104  }
105
106  // TODO: replace with version in common.reflect if and when it's open-sourced
107  private static <T> T newProxy(Class<T> interfaceType, InvocationHandler handler) {
108    Object object =
109        Proxy.newProxyInstance(
110            interfaceType.getClassLoader(), new Class<?>[] {interfaceType}, handler);
111    return interfaceType.cast(object);
112  }
113
114  private <T extends @Nullable Object> T callWithTimeout(
115      Callable<T> callable, long timeoutDuration, TimeUnit timeoutUnit, boolean amInterruptible)
116      throws Exception {
117    checkNotNull(callable);
118    checkNotNull(timeoutUnit);
119    checkPositiveTimeout(timeoutDuration);
120
121    Future<T> future = executor.submit(callable);
122
123    try {
124      if (amInterruptible) {
125        try {
126          return future.get(timeoutDuration, timeoutUnit);
127        } catch (InterruptedException e) {
128          future.cancel(true);
129          throw e;
130        }
131      } else {
132        return Uninterruptibles.getUninterruptibly(future, timeoutDuration, timeoutUnit);
133      }
134    } catch (ExecutionException e) {
135      throw throwCause(e, true /* combineStackTraces */);
136    } catch (TimeoutException e) {
137      future.cancel(true);
138      throw new UncheckedTimeoutException(e);
139    }
140  }
141
142  @CanIgnoreReturnValue
143  @Override
144  public <T extends @Nullable Object> T callWithTimeout(
145      Callable<T> callable, long timeoutDuration, TimeUnit timeoutUnit)
146      throws TimeoutException, InterruptedException, ExecutionException {
147    checkNotNull(callable);
148    checkNotNull(timeoutUnit);
149    checkPositiveTimeout(timeoutDuration);
150
151    Future<T> future = executor.submit(callable);
152
153    try {
154      return future.get(timeoutDuration, timeoutUnit);
155    } catch (InterruptedException | TimeoutException e) {
156      future.cancel(true /* mayInterruptIfRunning */);
157      throw e;
158    } catch (ExecutionException e) {
159      wrapAndThrowExecutionExceptionOrError(e.getCause());
160      throw new AssertionError();
161    }
162  }
163
164  @CanIgnoreReturnValue
165  @Override
166  public <T extends @Nullable Object> T callUninterruptiblyWithTimeout(
167      Callable<T> callable, long timeoutDuration, TimeUnit timeoutUnit)
168      throws TimeoutException, ExecutionException {
169    checkNotNull(callable);
170    checkNotNull(timeoutUnit);
171    checkPositiveTimeout(timeoutDuration);
172
173    Future<T> future = executor.submit(callable);
174
175    try {
176      return Uninterruptibles.getUninterruptibly(future, timeoutDuration, timeoutUnit);
177    } catch (TimeoutException e) {
178      future.cancel(true /* mayInterruptIfRunning */);
179      throw e;
180    } catch (ExecutionException e) {
181      wrapAndThrowExecutionExceptionOrError(e.getCause());
182      throw new AssertionError();
183    }
184  }
185
186  @Override
187  public void runWithTimeout(Runnable runnable, long timeoutDuration, TimeUnit timeoutUnit)
188      throws TimeoutException, InterruptedException {
189    checkNotNull(runnable);
190    checkNotNull(timeoutUnit);
191    checkPositiveTimeout(timeoutDuration);
192
193    Future<?> future = executor.submit(runnable);
194
195    try {
196      future.get(timeoutDuration, timeoutUnit);
197    } catch (InterruptedException | TimeoutException e) {
198      future.cancel(true /* mayInterruptIfRunning */);
199      throw e;
200    } catch (ExecutionException e) {
201      wrapAndThrowRuntimeExecutionExceptionOrError(e.getCause());
202      throw new AssertionError();
203    }
204  }
205
206  @Override
207  public void runUninterruptiblyWithTimeout(
208      Runnable runnable, long timeoutDuration, TimeUnit timeoutUnit) throws TimeoutException {
209    checkNotNull(runnable);
210    checkNotNull(timeoutUnit);
211    checkPositiveTimeout(timeoutDuration);
212
213    Future<?> future = executor.submit(runnable);
214
215    try {
216      Uninterruptibles.getUninterruptibly(future, timeoutDuration, timeoutUnit);
217    } catch (TimeoutException e) {
218      future.cancel(true /* mayInterruptIfRunning */);
219      throw e;
220    } catch (ExecutionException e) {
221      wrapAndThrowRuntimeExecutionExceptionOrError(e.getCause());
222      throw new AssertionError();
223    }
224  }
225
226  private static Exception throwCause(Exception e, boolean combineStackTraces) throws Exception {
227    Throwable cause = e.getCause();
228    if (cause == null) {
229      throw e;
230    }
231    if (combineStackTraces) {
232      StackTraceElement[] combined =
233          ObjectArrays.concat(cause.getStackTrace(), e.getStackTrace(), StackTraceElement.class);
234      cause.setStackTrace(combined);
235    }
236    if (cause instanceof Exception) {
237      throw (Exception) cause;
238    }
239    if (cause instanceof Error) {
240      throw (Error) cause;
241    }
242    // The cause is a weird kind of Throwable, so throw the outer exception.
243    throw e;
244  }
245
246  private static Set<Method> findInterruptibleMethods(Class<?> interfaceType) {
247    Set<Method> set = Sets.newHashSet();
248    for (Method m : interfaceType.getMethods()) {
249      if (declaresInterruptedEx(m)) {
250        set.add(m);
251      }
252    }
253    return set;
254  }
255
256  private static boolean declaresInterruptedEx(Method method) {
257    for (Class<?> exType : method.getExceptionTypes()) {
258      // debate: == or isAssignableFrom?
259      if (exType == InterruptedException.class) {
260        return true;
261      }
262    }
263    return false;
264  }
265
266  private void wrapAndThrowExecutionExceptionOrError(Throwable cause) throws ExecutionException {
267    if (cause instanceof Error) {
268      throw new ExecutionError((Error) cause);
269    } else if (cause instanceof RuntimeException) {
270      throw new UncheckedExecutionException(cause);
271    } else {
272      throw new ExecutionException(cause);
273    }
274  }
275
276  private void wrapAndThrowRuntimeExecutionExceptionOrError(Throwable cause) {
277    if (cause instanceof Error) {
278      throw new ExecutionError((Error) cause);
279    } else {
280      throw new UncheckedExecutionException(cause);
281    }
282  }
283
284  private static void checkPositiveTimeout(long timeoutDuration) {
285    checkArgument(timeoutDuration > 0, "timeout must be positive: %s", timeoutDuration);
286  }
287}