public static String caseConvert(String str)
    {
        StringBuffer buf = new StringBuffer();
        int length = str.length();
        for( int i = 0; i < length; i++)
        {
            char ch = str.charAt(i);
            if(Character.isUpperCase(ch))
            {
                buf.append(Character.toLowerCase(ch));
            }
            else
            {
                buf.append(Character.toUpperCase(ch));
            }
        }
        return buf.toString();
    }