}

  private void doClose(Closeable closeable, boolean swallowException) throws IOException {
    doClose(closeable, swallowException, !swallowException);
  }

  // Close the closeable using the Closeables, passing in the swallowException
  // parameter. expectThrown determines whether we expect an exception to
  // be thrown by Closeables.close;
  private void doClose(Closeable closeable, boolean swallowException, boolean expectThrown)

   * or extract a variable, and put the suppression on that. However, a local variable typically
   * doesn't work: Because nullness analyses typically infer the nullness of local variables,
   * there's no way to assign a {@code @Nullable T} to a field {@code T foo;} and instruct the
   * analysis that that means "plain {@code T}" rather than the inferred type {@code @Nullable T}.

                (v1, v2) -> {
                  throw new IllegalArgumentException("Multiple values for key: " + v1 + ", " + v2);
                }),
        (accum, t) -> {
          /*
           * We assign these to variables before calling checkNotNull to work around a bug in our
           * nullness checker.
           */
          K key = keyFunction.apply(t);
          V newValue = valueFunction.apply(t);

 *       #FileBackedOutputStream(int) the 1-arg constructor} or the {@linkplain
 *       #FileBackedOutputStream(int, boolean) 2-arg constructor} passing {@code false} in the
 *       second parameter.
 * </ul>
 *
 * <p>This class is thread-safe.
 *
 * @author Chris Nokleberg
 * @since 1.0
 */
@Beta
@J2ktIncompatible
@GwtIncompatible

   * <p>The returned object is serializable if {@code function} is serializable.
   *
   * @param function the function to be used for loading values; must never return {@code null}
   * @return a cache loader that loads values by passing each key to {@code function}
   */
  public static <K, V> CacheLoader<K, V> from(Function<K, V> function) {
    return new FunctionToCacheLoader<>(function);
  }

  /**

      fail("no exception thrown");
    } catch (IllegalArgumentException e) {
      assertThat(e).hasMessageThat().isEqualTo("A null C");
    }
  }

  @J2ktIncompatible // TODO(b/319404022): Allow passing null array as varargs
  public void testCheckArgument_singleNullArray_failure() {
    try {
      Preconditions.checkArgument(false, "A %s C", (Object[]) null);
      fail("no exception thrown");

 * </ul>
 *
 * @author Jens Nyman
 * @param <N> Node parameter type
 * @since 23.1
 */
@Beta
@DoNotMock(
    "Call forGraph or forTree, passing a lambda or a Graph with the desired edges (built with"
        + " GraphBuilder)")
@ElementTypesAreNonnullByDefault
public abstract class Traverser<N> {
  private final SuccessorsFunction<N> successorFunction;

   * aren't annotated nullable (according to the rules of {@link NullPointerTester}). In details:
   *
   * <ul>
   *   <li>All non-private static methods are checked such that passing null for any parameter
   *       that's not annotated nullable should throw {@link NullPointerException}.
   *   <li>If there is any non-private constructor or non-private static factory method declared by

   *     of this class typically expect for instances to have a non-null cause. At the moment, you
   *     can <i>usually</i> still preserve behavior by passing an explicit {@code null} cause. Note,
   *     however, that passing an explicit {@code null} cause prevents anyone from calling {@link
   *     #initCause} later, so it is not quite equivalent to using a constructor that omits the
   *     cause.
   */

    Ordering<Number> j = objects.compound(numbers.compound(objects)); // bad IDEA
    Ordering<Number> k = objects.compound(objects.compound(numbers));

    // You can also arbitrarily assign a more restricted type - not an intended
    // feature, exactly, but unavoidable (I think) and harmless
    Ordering<Integer> l = objects.compound(numbers);

    // This correctly doesn't work: