* @throws IllegalArgumentException if {@code separatorPattern} matches the empty string
   */
  @GwtIncompatible // java.util.regex
  public static Splitter on(Pattern separatorPattern) {
    return onPatternInternal(new JdkPattern(separatorPattern));
  }

  /** Internal utility; see {@link #on(Pattern)} instead. */
  static Splitter onPatternInternal(CommonPattern separatorPattern) {
    checkArgument(

   *
   * @since 3.0
   */
  @GwtIncompatible // java.util.regex.Pattern
  public static Predicate<CharSequence> contains(Pattern pattern) {
    return new ContainsPatternPredicate(new JdkPattern(pattern));
  }

  // End public API, begin private implementation classes.

  private enum ObjectPredicate implements Predicate<@Nullable Object> {
    /**
     * @see Predicates#alwaysTrue()
     */

   *
   * @since 3.0
   */
  @GwtIncompatible // java.util.regex.Pattern
  public static Predicate<CharSequence> contains(Pattern pattern) {
    return new ContainsPatternPredicate(new JdkPattern(pattern));
  }

  // End public API, begin private implementation classes.

  private enum ObjectPredicate implements Predicate<@Nullable Object> {
    /**
     * @see Predicates#alwaysTrue()
     */

   * @throws IllegalArgumentException if {@code separatorPattern} matches the empty string
   */
  @GwtIncompatible // java.util.regex
  public static Splitter on(Pattern separatorPattern) {
    return onPatternInternal(new JdkPattern(separatorPattern));
  }

  /** Internal utility; see {@link #on(Pattern)} instead. */
  static Splitter onPatternInternal(CommonPattern separatorPattern) {
    checkArgument(