/*
 * Copyright (C) 2006 The Guava Authors
 *
 * Licensed 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 com.google.common.util.concurrent;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;

import com.google.common.annotations.Beta;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.collect.ObjectArrays;
import com.google.common.collect.Sets;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.Set;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

A TimeLimiter that runs method calls in the background using an ExecutorService. If the time limit expires for a given method call, the thread running the call will be interrupted.
Author:Kevin Bourrillion, Jens Nyman
Since:1.0
/** * A TimeLimiter that runs method calls in the background using an {@link ExecutorService}. If the * time limit expires for a given method call, the thread running the call will be interrupted. * * @author Kevin Bourrillion * @author Jens Nyman * @since 1.0 */
@Beta @GwtIncompatible public final class SimpleTimeLimiter implements TimeLimiter { private final ExecutorService executor; private SimpleTimeLimiter(ExecutorService executor) { this.executor = checkNotNull(executor); }
Creates a TimeLimiter instance using the given executor service to execute method calls.

Warning: using a bounded executor may be counterproductive! If the thread pool fills up, any time callers spend waiting for a thread may count toward their time limit, and in this case the call may even time out before the target method is ever invoked.

Params:
Since:22.0
/** * Creates a TimeLimiter instance using the given executor service to execute method calls. * * <p><b>Warning:</b> using a bounded executor may be counterproductive! If the thread pool fills * up, any time callers spend waiting for a thread may count toward their time limit, and in this * case the call may even time out before the target method is ever invoked. * * @param executor the ExecutorService that will execute the method calls on the target objects; * for example, a {@link Executors#newCachedThreadPool()}. * @since 22.0 */
public static SimpleTimeLimiter create(ExecutorService executor) { return new SimpleTimeLimiter(executor); } @Override public <T> T newProxy( final T target, Class<T> interfaceType, final long timeoutDuration, final TimeUnit timeoutUnit) { checkNotNull(target); checkNotNull(interfaceType); checkNotNull(timeoutUnit); checkPositiveTimeout(timeoutDuration); checkArgument(interfaceType.isInterface(), "interfaceType must be an interface type"); final Set<Method> interruptibleMethods = findInterruptibleMethods(interfaceType); InvocationHandler handler = new InvocationHandler() { @Override public Object invoke(Object obj, final Method method, final Object[] args) throws Throwable { Callable<Object> callable = new Callable<Object>() { @Override public Object call() throws Exception { try { return method.invoke(target, args); } catch (InvocationTargetException e) { throw throwCause(e, false /* combineStackTraces */); } } }; return callWithTimeout( callable, timeoutDuration, timeoutUnit, interruptibleMethods.contains(method)); } }; return newProxy(interfaceType, handler); } // TODO: replace with version in common.reflect if and when it's open-sourced private static <T> T newProxy(Class<T> interfaceType, InvocationHandler handler) { Object object = Proxy.newProxyInstance( interfaceType.getClassLoader(), new Class<?>[] {interfaceType}, handler); return interfaceType.cast(object); } private <T> T callWithTimeout( Callable<T> callable, long timeoutDuration, TimeUnit timeoutUnit, boolean amInterruptible) throws Exception { checkNotNull(callable); checkNotNull(timeoutUnit); checkPositiveTimeout(timeoutDuration); Future<T> future = executor.submit(callable); try { if (amInterruptible) { try { return future.get(timeoutDuration, timeoutUnit); } catch (InterruptedException e) { future.cancel(true); throw e; } } else { return Uninterruptibles.getUninterruptibly(future, timeoutDuration, timeoutUnit); } } catch (ExecutionException e) { throw throwCause(e, true /* combineStackTraces */); } catch (TimeoutException e) { future.cancel(true); throw new UncheckedTimeoutException(e); } } @CanIgnoreReturnValue @Override public <T> T callWithTimeout(Callable<T> callable, long timeoutDuration, TimeUnit timeoutUnit) throws TimeoutException, InterruptedException, ExecutionException { checkNotNull(callable); checkNotNull(timeoutUnit); checkPositiveTimeout(timeoutDuration); Future<T> future = executor.submit(callable); try { return future.get(timeoutDuration, timeoutUnit); } catch (InterruptedException | TimeoutException e) { future.cancel(true /* mayInterruptIfRunning */); throw e; } catch (ExecutionException e) { wrapAndThrowExecutionExceptionOrError(e.getCause()); throw new AssertionError(); } } @CanIgnoreReturnValue @Override public <T> T callUninterruptiblyWithTimeout( Callable<T> callable, long timeoutDuration, TimeUnit timeoutUnit) throws TimeoutException, ExecutionException { checkNotNull(callable); checkNotNull(timeoutUnit); checkPositiveTimeout(timeoutDuration); Future<T> future = executor.submit(callable); try { return Uninterruptibles.getUninterruptibly(future, timeoutDuration, timeoutUnit); } catch (TimeoutException e) { future.cancel(true /* mayInterruptIfRunning */); throw e; } catch (ExecutionException e) { wrapAndThrowExecutionExceptionOrError(e.getCause()); throw new AssertionError(); } } @Override public void runWithTimeout(Runnable runnable, long timeoutDuration, TimeUnit timeoutUnit) throws TimeoutException, InterruptedException { checkNotNull(runnable); checkNotNull(timeoutUnit); checkPositiveTimeout(timeoutDuration); Future<?> future = executor.submit(runnable); try { future.get(timeoutDuration, timeoutUnit); } catch (InterruptedException | TimeoutException e) { future.cancel(true /* mayInterruptIfRunning */); throw e; } catch (ExecutionException e) { wrapAndThrowRuntimeExecutionExceptionOrError(e.getCause()); throw new AssertionError(); } } @Override public void runUninterruptiblyWithTimeout( Runnable runnable, long timeoutDuration, TimeUnit timeoutUnit) throws TimeoutException { checkNotNull(runnable); checkNotNull(timeoutUnit); checkPositiveTimeout(timeoutDuration); Future<?> future = executor.submit(runnable); try { Uninterruptibles.getUninterruptibly(future, timeoutDuration, timeoutUnit); } catch (TimeoutException e) { future.cancel(true /* mayInterruptIfRunning */); throw e; } catch (ExecutionException e) { wrapAndThrowRuntimeExecutionExceptionOrError(e.getCause()); throw new AssertionError(); } } private static Exception throwCause(Exception e, boolean combineStackTraces) throws Exception { Throwable cause = e.getCause(); if (cause == null) { throw e; } if (combineStackTraces) { StackTraceElement[] combined = ObjectArrays.concat(cause.getStackTrace(), e.getStackTrace(), StackTraceElement.class); cause.setStackTrace(combined); } if (cause instanceof Exception) { throw (Exception) cause; } if (cause instanceof Error) { throw (Error) cause; } // The cause is a weird kind of Throwable, so throw the outer exception. throw e; } private static Set<Method> findInterruptibleMethods(Class<?> interfaceType) { Set<Method> set = Sets.newHashSet(); for (Method m : interfaceType.getMethods()) { if (declaresInterruptedEx(m)) { set.add(m); } } return set; } private static boolean declaresInterruptedEx(Method method) { for (Class<?> exType : method.getExceptionTypes()) { // debate: == or isAssignableFrom? if (exType == InterruptedException.class) { return true; } } return false; } private void wrapAndThrowExecutionExceptionOrError(Throwable cause) throws ExecutionException { if (cause instanceof Error) { throw new ExecutionError((Error) cause); } else if (cause instanceof RuntimeException) { throw new UncheckedExecutionException(cause); } else { throw new ExecutionException(cause); } } private void wrapAndThrowRuntimeExecutionExceptionOrError(Throwable cause) { if (cause instanceof Error) { throw new ExecutionError((Error) cause); } else { throw new UncheckedExecutionException(cause); } } private static void checkPositiveTimeout(long timeoutDuration) { checkArgument(timeoutDuration > 0, "timeout must be positive: %s", timeoutDuration); } }