assertToStringWorks("CharMatcher.none()", CharMatcher.anyOf(""));
    assertToStringWorks("CharMatcher.is('\\u0031')", CharMatcher.anyOf("1"));
    assertToStringWorks("CharMatcher.isNot('\\u0031')", CharMatcher.isNot('1'));
    assertToStringWorks("CharMatcher.anyOf(\"\\u0031\\u0032\")", CharMatcher.anyOf("12"));
    assertToStringWorks("CharMatcher.anyOf(\"\\u0031\\u0032\\u0033\")", CharMatcher.anyOf("321"));

    assertToStringWorks("CharMatcher.none()", CharMatcher.anyOf(""));
    assertToStringWorks("CharMatcher.is('\\u0031')", CharMatcher.anyOf("1"));
    assertToStringWorks("CharMatcher.isNot('\\u0031')", CharMatcher.isNot('1'));
    assertToStringWorks("CharMatcher.anyOf(\"\\u0031\\u0032\")", CharMatcher.anyOf("12"));
    assertToStringWorks("CharMatcher.anyOf(\"\\u0031\\u0032\\u0033\")", CharMatcher.anyOf("321"));

            .or(CharMatcher.inRange('A', 'Z'))
            .or(CharMatcher.anyOf("äöüßÄÖÜ")),
        "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZäöüßÄÖÜ");

    public final CharMatcher matcher;
    public final String matchingChars;

    SampleMatcherConfig(String matchingChars) {
      this(CharMatcher.anyOf(matchingChars), matchingChars);
    }

    @Override
    public String toString() {
      return "CharMatcher.anyOf(\"" + showCharacter(match1) + showCharacter(match2) + "\")";
    }
  }

  /** Implementation of {@link #anyOf(CharSequence)} for three or more characters. */
  private static final class AnyOf extends CharMatcher {

    private final char[] chars;

    AnyOf(CharSequence chars) {
      this.chars = chars.toString().toCharArray();

    String jacksons = "arfo(Marlon)aorf, (Michael)orfa, afro(Jackie)orfa, ofar(Jemaine), aff(Tito)";
    Iterable<String> family =
        COMMA_SPLITTER
            .trimResults(CharMatcher.anyOf("afro").or(CharMatcher.whitespace()))
            .split(jacksons);
    assertThat(family)
        .containsExactly("(Marlon)", "(Michael)", "(Jackie)", "(Jemaine)", "(Tito)")
        .inOrder();
  }

 * versions.
 *
 * @author Catherine Berry
 * @since 5.0
 */
@GwtCompatible
@Immutable
public final class InternetDomainName {

  private static final CharMatcher DOTS_MATCHER = CharMatcher.anyOf(".\u3002\uFF0E\uFF61");
  private static final Splitter DOT_SPLITTER = Splitter.on('.');
  private static final Joiner DOT_JOINER = Joiner.on('.');

  /**