import java.util.logging.Level;

/**
 * A list of listeners for implementing a concurrency friendly observable object.
 *
 * <p>Listeners are registered once via {@link #addListener} and then may be invoked by {@linkplain
 * #enqueue enqueueing} and then {@linkplain #dispatch dispatching} events.
 *
 * <p>The API of this class is designed to make it easy to achieve the following properties
 *
 * <ul>

  /**
   * The maximum number of requests to execute concurrently. Above this requests queue in memory,
   * waiting for the running calls to complete.
   *
   * If more than [maxRequests] requests are in flight when this is invoked, those requests will
   * remain in flight.
   */
  @get:Synchronized
  var maxRequests = 64
    set(maxRequests) {
      require(maxRequests >= 1) { "max < 1: $maxRequests" }
      synchronized(this) {

   * <p>This method should return promptly; prefer to do work on a different thread where it is
   * convenient. It is invoked exactly once on service shutdown, even when {@link #stopAsync} is
   * called multiple times.
   *
   * <p>If {@link #stopAsync} is called on a {@link State#STARTING} service, this method is not
   * invoked immediately. Instead, it will be deferred until after the service is {@link

import java.util.ConcurrentModificationException;
import java.util.Iterator;
import org.junit.Ignore;

/**
 * A generic JUnit test which tests {@code add(int, Object)} operations on a list. Can't be invoked
 * directly; please see {@link com.google.common.collect.testing.ListTestSuiteBuilder}.
 *
 * @author Chris Povirk
 */
@GwtCompatible

import com.google.common.annotations.GwtCompatible;
import org.junit.Ignore;

/**
 * A generic JUnit test which tests {@code get()} operations on a list. Can't be invoked directly;
 * please see {@link com.google.common.collect.testing.ListTestSuiteBuilder}.
 *
 * @author Chris Povirk
 */
@GwtCompatible

   * a duration in order to call a legacy API which requires a {@code long, TimeUnit} pair.
   */
  static long toNanosSaturated(Duration duration) {
    // Using a try/catch seems lazy, but the catch block will rarely get invoked (except for
    // durations longer than approximately +/- 292 years).
    try {
      return duration.toNanos();
    } catch (ArithmeticException tooBig) {

  @IgnoreJRERequirement
  static long toNanosSaturated(Duration duration) {
    // Using a try/catch seems lazy, but the catch block will rarely get invoked (except for
    // durations longer than approximately +/- 292 years).
    try {
      return duration.toNanos();
    } catch (ArithmeticException tooBig) {

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.testing.AbstractMapTester;
import org.junit.Ignore;

/**
 * A generic JUnit test which tests {@code size()} operations on a map. Can't be invoked directly;
 * please see {@link com.google.common.collect.testing.MapTestSuiteBuilder}.
 *
 * @author George van den Driessche
 */
@GwtCompatible

    @Override
    protected @Nullable Object handleInvocation(
        Object p, Method calledMethod, @Nullable Object[] args) throws Throwable {
      assertEquals(method, calledMethod);
      assertEquals(method + " invoked more than once.", 0, called.get());
      for (int i = 0; i < passedArgs.length; i++) {
        assertEquals(
            "Parameter #" + i + " of " + method + " not forwarded", passedArgs[i], args[i]);
      }

import com.google.common.collect.testing.features.CollectionSize;
import java.util.NoSuchElementException;
import org.junit.Ignore;

/**
 * A generic JUnit test which tests {@code element()} operations on a queue. Can't be invoked
 * directly; please see {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}.
 *
 * @author Jared Levy
 */
@GwtCompatible