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;
      activeGuards = guard;

    // (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

  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;
    }

TensorFlow coding style.

#### General guidelines and philosophy for contribution

*   Include unit tests when you contribute new features, as they help to a)
    prove that your code works correctly, and b) guard against future breaking
    changes to lower the maintenance cost.
*   Bug fixes also generally require unit tests, because the presence of bugs
    usually indicates insufficient test coverage.