for (Guard guard = activeGuards; guard != null; guard = guard.next) {
      guard.condition.signalAll();
    }
  }

  /** Records that the current thread is about to wait on the specified guard. */
  @GuardedBy("lock")
  private void beginWaitingFor(Guard guard) {
    int waiters = guard.waiterCount++;
    if (waiters == 0) {
      // push guard onto activeGuards
      guard.next = activeGuards;

  private final Guard isStartable = new IsStartableGuard();

  @WeakOuter
  private final class IsStartableGuard extends Guard {
    IsStartableGuard() {
      super(AbstractService.this.monitor);
    }

    @Override
    public boolean isSatisfied() {
      return state() == NEW;
    }
  }

  private final Guard isStoppable = new IsStoppableGuard();

  @WeakOuter

    // (b) Waiting for the single guard to become satisfied.
    // (c) Occupying the monitor and awaiting the tearDownLatch.
    //
    // Except for (c), every thread should occupy the monitor very briefly, and every thread leaves
    // the monitor with the guard satisfied. Therefore as soon as tearDownLatch is triggered, we
    // should be able to enter the monitor, and then we set the guard to satisfied for the benefit

  private final Guard isStartable = new IsStartableGuard();

  @WeakOuter
  private final class IsStartableGuard extends Guard {
    IsStartableGuard() {
      super(AbstractService.this.monitor);
    }

    @Override
    public boolean isSatisfied() {
      return state() == NEW;
    }
  }

  private final Guard isStoppable = new IsStoppableGuard();

  @WeakOuter

   * found in any textbook.
   */

  /** Monitor guarding all access */
  final Monitor monitor;

  /** Guard for waiting takes */
  private final Monitor.Guard notEmpty;

  /** Guard for waiting puts */
  private final Monitor.Guard notFull;

  // Internal helper methods

  /** Circularly increment i. */
  final int inc(int i) {
    return (++i == items.length) ? 0 : i;
  }

     * which it is guaranteed that it can never become healthy.
     */
    final Monitor.Guard awaitHealthGuard = new AwaitHealthGuard();

    @WeakOuter
    final class AwaitHealthGuard extends Monitor.Guard {
      AwaitHealthGuard() {
        super(ServiceManagerState.this.monitor);
      }

      @Override

  private static final long serialVersionUID = 5595510919245408276L;

  final PriorityQueue<E> q;
  final Monitor monitor = new Monitor(true);
  private final Monitor.Guard notEmpty =
      new Monitor.Guard(monitor) {
        @Override
        public boolean isSatisfied() {
          return !q.isEmpty();
        }
      };

  /**

  @J2ktIncompatible
  @GwtIncompatible // lazyStackTraceIsLazy()
  public void testLazyStackTraceWorksInProd() {
    // TODO(b/64442212): Remove this guard once lazyStackTrace() works in Java 9+.
    Integer javaVersion = Ints.tryParse(JAVA_SPECIFICATION_VERSION.value());
    if (javaVersion != null && javaVersion >= 9) {
      return;
    }

  @J2ktIncompatible
  @GwtIncompatible // lazyStackTraceIsLazy()
  public void testLazyStackTraceWorksInProd() {
    // TODO(b/64442212): Remove this guard once lazyStackTrace() works in Java 9+.
    Integer javaVersion = Ints.tryParse(JAVA_SPECIFICATION_VERSION.value());
    if (javaVersion != null && javaVersion >= 9) {
      return;
    }

   *
   * <p>Copying is not an atomic operation - in the case of an I/O error, power loss, process
   * termination, or other problems, {@code to} may not be a complete copy of {@code from}. If you
   * need to guard against those conditions, you should employ other file-level synchronization.
   *
   * <p><b>Warning:</b> If {@code to} represents an existing file, that file will be overwritten