return delegate.floor(checkValid(e));
  }

  @Override
  public SortedSet<E> headSet(E toElement) {
    return headSet(toElement, false);
  }

  @Override
  public NavigableSet<E> headSet(E toElement, boolean inclusive) {
    return new SafeTreeSet<>(delegate.headSet(checkValid(toElement), inclusive));
  }

  @Override
  public @Nullable E higher(E e) {

     * @param o
     *            element whose presence in this set is to be tested.
     * @return true if this set contains the specified element.
     */
    @Override
    public boolean contains(final Object o) {
        return map.containsKey(o);
    }

    /**
     * Adds the specified element to this set if it is not already present.
     *
     * @param o
     *            element to be added to this set.

        assertTrue(iterator.hasNext(), "Should have first element");
        SmbResource first = iterator.next();
        assertNotNull(first, "First element should not be null");
        assertEquals("file1.txt", first.getName());

        assertTrue(iterator.hasNext(), "Should have second element");
        SmbResource second = iterator.next();
        assertNotNull(second, "Second element should not be null");

    E[] elements = createSamplesArray();
    E duplicate = elements[(elements.length / 2) - 1];
    elements[(elements.length / 2) + 1] = duplicate;
    return new ArrayWithDuplicate<>(elements, duplicate);
  }

  // Helper methods to improve readability of derived classes

  protected int getNumElements() {
    return getSubjectGenerator().getCollectionSize().getNumElements();
  }

    public abstract Builder<E> add(E element);

    @CanIgnoreReturnValue
    public Builder<E> add(E... elements) {
      checkNotNull(elements); // for GWT
      for (E element : elements) {
        add(checkNotNull(element));
      }
      return this;
    }

    @CanIgnoreReturnValue
    public Builder<E> addAll(Iterable<? extends E> elements) {
      checkNotNull(elements); // for GWT

  @JsMethod(name = "of")
  static <E> ImmutableSet<E> jsOf(E... elements) {
    return copyOf(elements);
  }

  @JsMethod
  public static <E> ImmutableSet<E> copyOf(E[] elements) {
    checkNotNull(elements);
    switch (elements.length) {
      case 0:
        return of();
      case 1:
        return of(elements[0]);
      default:
        return create(elements);
    }
  }

  }

  protected void expectMissingKeys(K... elements) {
    for (K element : elements) {
      assertFalse("Should not contain key " + element, getMap().containsKey(element));
    }
  }

  protected void expectMissingValues(V... elements) {
    for (V element : elements) {
      assertFalse("Should not contain value " + element, getMap().containsValue(element));
    }
  }

  /**

    @Override
    protected List<String> create(String[] elements) {
      String[] suffix = {"f", "g"};
      String[] all = new String[elements.length + suffix.length];
      arraycopy(elements, 0, all, 0, elements.length);
      arraycopy(suffix, 0, all, elements.length, suffix.length);
      return ImmutableList.copyOf(all).subList(0, elements.length);
    }
  }

  /**
   * Returns a new array that prepends {@code element} to {@code array}.
   *
   * @param element the element to prepend to the front of {@code array}
   * @param array the array of elements to append
   * @return an array whose size is one larger than {@code array}, with {@code element} occupying
   *     the first position, and the elements of {@code array} occupying the remaining elements.
   */

 *
 * String[] array = ...;
 * for (String element : iterable(array)) {
 *     ...
 * }
 * </pre>
 *
 * @author shot
 * @param <T> the type of array elements
 */
public class ArrayIterator<T> implements Iterator<T> {

    /** The array of elements to iterate over */
    protected final T[] items;

    /** The index of the currently referenced element */
    protected int index = 0;

    /**