private static final String URL_REGEX = "^(https?://)" + "?(([0-9a-z_!~*'().&=+$%-]+: )?[0-9a-z_!~*'().&=+$%-]+@)?" //user@ + "(([0-9]{1,3}\\.){3}[0-9]{1,3}" // IP- 199.194.52.184 + "|" // allows either IP or domain + "([0-9a-z_!~*'()-]+\\.)*" // tertiary domain(s)- www. + "([0-9a-z][0-9a-z-]{0,61})?[0-9a-z]\\." // second level domain + "[a-z]{2,6})" // first level domain- .com or .museum + "(:[0-9]{1,4})?" // port number- :80 + "((/?)|" // a slash isn't required if there is no file name + "(/[0-9a-z_!~*'().;?:@&=+$,%#-]+)+/?)$";