private final Adder adder;

    FailsToForwardReturnValue(Adder adder) {
      this.adder = adder;
    }

    @Override
    public int add(int a, int b) {
      return adder.add(a, b) + 1;
    }

    @Override
    public String toString() {
      return adder.toString();
    }
  }

  private static class FailsToPropagateException implements Adder {

 * automate the process, often adding features like monitoring, debugging, and cancellation.
 * Examples of frameworks include:
 *
 * <ul>
 *   <li><a href="https://dagger.dev/producers.html">Dagger Producers</a>
 * </ul>
 *
 * <p>The main purpose of {@link #addListener addListener} is to support this chaining. You will

  private static final long serialVersionUID = 7249069246863182397L;

  /** Version of plus for use in retryUpdate */
  @Override
  final long fn(long v, long x) {
    return v + x;
  }

  /** Creates a new adder with initial sum of zero. */
  public LongAdder() {}

  /**
   * Adds the given value.
   *
   * @param x the value to add
   */
  @Override
  public void add(long x) {
    Cell[] as;
    long b, v;

        public Lock get() {
          return new ReentrantLock();
        }
      };

  @Param({"2", "8", "64", "1024", "65536"})
  int numStripes;

  @Param Impl impl;

  enum Impl {
    EAGER {
      @Override
      Striped<Lock> get(int stripes) {
        return Striped.lock(stripes);
      }
    },
    LAZY_SMALL {
      @Override
      Striped<Lock> get(int stripes) {

        public Lock get() {
          return new ReentrantLock();
        }
      };

  @Param({"2", "8", "64", "1024", "65536"})
  int numStripes;

  @Param Impl impl;

  enum Impl {
    EAGER {
      @Override
      Striped<Lock> get(int stripes) {
        return Striped.lock(stripes);
      }
    },
    LAZY_SMALL {
      @Override
      Striped<Lock> get(int stripes) {

    // we try hard to make them robust in practice.  We could additionally try to add in a system
    // load timeout multiplier.  Or we could try to use a CPU time bound instead of wall clock time
    // bound.  But these ideas are harder to implement.  We do not try to detect or handle a
    // user-specified -XX:+DisableExplicitGC.
    //
    // TODO(user): Consider using
    // java/lang/management/OperatingSystemMXBean.html#getSystemLoadAverage()

  }

  // enum singleton pattern
  private enum ToStringFunction implements Function<Object, String> {
    INSTANCE;

    @Override
    public String apply(Object o) {
      checkNotNull(o); // eager for GWT.
      return o.toString();
    }

    @Override
    public String toString() {
      return "Functions.toStringFunction()";
    }
  }

  /**
   * Returns the identity function.
   *

   * a good policy, especially because, in order for the test to pass, the
   * parameter must be misleadingly annotated as @Nullable. I suspect that
   * we'll want to remove @Nullable, add an eager checkNotNull, and loosen up
   * testRemove_nullAllowed.
   */
  @CanIgnoreReturnValue
  @Override
  public int remove(@CheckForNull Object element, int occurrences) {
    if (occurrences == 0) {

 * find it easier to use a framework. Frameworks automate the process, often adding features like
 * monitoring, debugging, and cancellation. Examples of frameworks include:
 *
 * <ul>
 *   <li><a href="https://dagger.dev/producers.html">Dagger Producers</a>
 * </ul>
 *
 * <p>If you do chain your operations manually, you may want to use {@link FluentFuture}.
 *
 * @author Kevin Bourrillion
 * @author Nishant Thakkar
 * @author Sven Mawson

    if (!expression) {
      throw new IllegalStateException(lenientFormat(errorMessageTemplate, p1, p2, p3, p4));
    }
  }

  /*
   * Preconditions.checkNotNull is *intended* for performing eager null checks on parameters that a
   * nullness checker can already "prove" are non-null. That means that the first parameter to
   * checkNotNull *should* be annotated to require it to be non-null.
   *