String[] array = new String[elements.length];
    int i = 0;
    for (Object e : elements) {
      array[i++] = (String) e;
    }
    return create(array);
  }

  protected abstract Queue<String> create(String[] elements);

  @Override
  public String[] createArray(int length) {
    return new String[length];
  }

  /** Returns the original element list, unchanged. */
  @Override

    String[] array = new String[elements.length];
    int i = 0;
    for (Object e : elements) {
      array[i++] = (String) e;
    }
    return create(array);
  }

  /**
   * Creates a new collection containing the given elements; implement this method instead of {@link
   * #create(Object...)}.
   */
  protected abstract List<String> create(String[] elements);

  @Override

            return StringUtil.EMPTY_STRINGS;
        }
        return split(value, ",").get(stream -> stream.filter(StringUtil::isNotBlank).map(String::trim).toArray(n -> new String[n]));
    }

    public static class OpenIdUser implements FessUser {

        private static final long serialVersionUID = 1L;

        protected final String name;

        protected String[] groups;

        protected String[] roles;

    @Override
    protected Set<String> create(String[] elements) {
      return ImmutableSet.copyOf(elements);
    }
  }

  public static class ImmutableSetUnsizedBuilderGenerator extends TestStringSetGenerator {
    @Override
    protected Set<String> create(String[] elements) {
      ImmutableSet.Builder<String> builder = ImmutableSet.builder();
      for (String e : elements) {
        builder.add(e);
      }

  private static final String DELTA = "\u0394";

  /** A domain part which is valid under lenient validation, but invalid under strict validation. */
  static final String LOTS_OF_DELTAS = Strings.repeat(DELTA, 62);

  private static final String ALMOST_TOO_MANY_LEVELS = Strings.repeat("a.", 127);

  private static final String ALMOST_TOO_LONG = Strings.repeat("aaaaa.", 40) + "1234567890.c";

  static final Integer NODE_NOT_IN_GRAPH = 1000;

  // TODO(user): Consider separating Strings that we've defined here to capture
  // identifiable substrings of expected error messages, from Strings that we've defined
  // here to provide error messages.
  // TODO(user): Some Strings used in the subclasses can be added as static Strings
  // here too.
  static final String ERROR_MODIFIABLE_SET = "Set returned is unexpectedly modifiable";

        assertNull(DocumentUtil.getValue(doc, "key2", String.class));
    }

    public void test_strings() {
        Map<String, Object> doc = new HashMap<>();
        doc.put("key1", new String[] { "aaa", "bbb" });
        assertArrayEquals(new String[] { "aaa", "bbb" }, DocumentUtil.getValue(doc, "key1", String[].class));
        assertEquals(Arrays.asList("aaa", "bbb"), (List<String>) DocumentUtil.getValue(doc, "key1", List.class));
    }

    Ordering<String> ordering = Ordering.natural();
    Ordering<Iterable<String>> lexy = ordering.lexicographical();

    ImmutableList<String> empty = ImmutableList.of();
    ImmutableList<String> a = ImmutableList.of("a");
    ImmutableList<String> aa = ImmutableList.of("a", "a");
    ImmutableList<String> ab = ImmutableList.of("a", "b");
    ImmutableList<String> b = ImmutableList.of("b");

    Ordering<String> ordering = Ordering.natural();
    Ordering<Iterable<String>> lexy = ordering.lexicographical();

    ImmutableList<String> empty = ImmutableList.of();
    ImmutableList<String> a = ImmutableList.of("a");
    ImmutableList<String> aa = ImmutableList.of("a", "a");
    ImmutableList<String> ab = ImmutableList.of("a", "b");
    ImmutableList<String> b = ImmutableList.of("b");

            if (fessConfig.hasNotification()) {
                final String toStrs = fessConfig.getNotificationTo();
                final String[] toAddresses;
                if (StringUtil.isNotBlank(toStrs)) {
                    toAddresses = toStrs.split(",");
                } else {
                    toAddresses = StringUtil.EMPTY_STRINGS;
                }