All Downloads are FREE. Search and download functionalities are using the official Maven repository.
  • Log In
  • Register

    • com.google.common.util.concurrent.SimpleTimeLimiter Maven / Gradle / Ivy

    Go to download

    This artifact provides a single jar that contains all classes required to use remote Jakarta Enterprise Beans and Jakarta Messaging, including all dependencies. It is intended for use by those not using maven, maven users should just import the Jakarta Enterprise Beans and Jakarta Messaging BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

    There is a newer version: 35.0.0.Beta1
    Show newest version
    /*
 * 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.collect.ObjectArrays;
import com.google.common.collect.Sets;

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
 * {@link ExecutorService}.  If the time limit expires for a given method call,
 * the thread running the call will be interrupted.
 *
 * @author Kevin Bourrillion
 * @since 1.0
 */
@Beta
public final class SimpleTimeLimiter implements TimeLimiter {

  private final ExecutorService executor;

  /**
   * Constructs a TimeLimiter instance using the given executor service to
   * execute proxied 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.
   *
   * @param executor the ExecutorService that will execute the method calls on
   *     the target objects; for example, a {@link
   *     Executors#newCachedThreadPool()}.
   */
  public SimpleTimeLimiter(ExecutorService executor) {
    this.executor = checkNotNull(executor);
  }

  /**
   * Constructs a TimeLimiter instance using a {@link
   * Executors#newCachedThreadPool()} to execute proxied 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.
   */
  public SimpleTimeLimiter() {
    this(Executors.newCachedThreadPool());
  }

  @Override
  public  T newProxy(final T target, Class interfaceType,
      final long timeoutDuration, final TimeUnit timeoutUnit) {
    checkNotNull(target);
    checkNotNull(interfaceType);
    checkNotNull(timeoutUnit);
    checkArgument(timeoutDuration > 0, "bad timeout: %s", timeoutDuration);
    checkArgument(interfaceType.isInterface(),
        "interfaceType must be an interface type");

    final Set interruptibleMethods
        = findInterruptibleMethods(interfaceType);

    InvocationHandler handler = new InvocationHandler() {
      @Override
      public Object invoke(Object obj, final Method method, final Object[] args)
          throws Throwable {
        Callable callable = new Callable() {
          @Override
          public Object call() throws Exception {
            try {
              return method.invoke(target, args);
            } catch (InvocationTargetException e) {
              throwCause(e, false);
              throw new AssertionError("can't get here");
            }
          }
        };
        return callWithTimeout(callable, timeoutDuration, timeoutUnit,
            interruptibleMethods.contains(method));
      }
    };
    return newProxy(interfaceType, handler);
  }

  // TODO: should this actually throw only ExecutionException?
  @Override
  public  T callWithTimeout(Callable callable, long timeoutDuration,
      TimeUnit timeoutUnit, boolean amInterruptible) throws Exception {
    checkNotNull(callable);
    checkNotNull(timeoutUnit);
    checkArgument(timeoutDuration > 0, "timeout must be positive: %s",
        timeoutDuration);
    Future 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);
    } catch (TimeoutException e) {
      future.cancel(true);
      throw new UncheckedTimeoutException(e);
    }
  }

  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 findInterruptibleMethods(Class interfaceType) {
    Set 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;
  }

  // TODO: replace with version in common.reflect if and when it's open-sourced
  private static  T newProxy(
      Class interfaceType, InvocationHandler handler) {
    Object object = Proxy.newProxyInstance(interfaceType.getClassLoader(),
        new Class[] { interfaceType }, handler);
    return interfaceType.cast(object);
  }
}
    
    
    
    

    




    
    
    © 2015 - 2025 Weber Informatics LLC | Privacy Policy