Research on optimization method of regular expression in data validation based on DFA

Regular expression is one of the most powerful input control technologies. However, processing regular expression for computer is difficult. This paper proposes a method to match token string by using the Min-DFA which is equal to regular expression. In this method, the input regular expression is converted into an equivalent NFA, and then, DFA. After that, a minimizing procedure can be executed. Finally, a Minimal DFA can be maintained by the system and can be used to matching the string which is equal with it. Examples showed that our method optimized the procedure of data validation.