private static boolean analyzeBranch(RegExpBranch branch) {
    final RegExpAtom[] atoms = branch.getAtoms();
    for (RegExpAtom atom : atoms) {
      if (!(atom instanceof RegExpChar) || ((RegExpChar)atom).getValue() == -1) {
        return false;
      }
      else if (((RegExpChar)atom).getType() != RegExpChar.Type.CHAR) {
        // this could probably allow more, such as escape sequences
        return false;
      }
    }
    return true;
  }
private static boolean analyzeBranch(RegExpBranch branch)