[프로그래머스][JAVA] 신규 아이디 추천 (String)

class Solution {
    public static String solution(String new_id) {
        String answer = new KAKAOID(new_id)
                .replaceToLowerCase()
                .filter()
                .toSingleDot()
                .deleteStartEndDot()
                .noBlank()
                .noGreaterThan16()
                .noLessThan2()
                .getResult();
        
        
        return answer;
    }
    
    private static class KAKAOID{
        private String s;
        public KAKAOID(String s) {
            this.s = s;
        } 
        
        private KAKAOID replaceToLowerCase() {
            s = s.toLowerCase();
            return this;
        }
        
        private KAKAOID filter() {
            s = s.replaceAll("[^a-z0-9_.-]","");
            return this;
        }
        
        private KAKAOID toSingleDot() {
            s = s.replaceAll("[.]{2,}",".");
            return this;
        }
        
        private KAKAOID deleteStartEndDot() {
            s = s.replaceAll("^[.]|[.]$","");
            return this;
        }
        
        private KAKAOID noBlank() {
            s = s.isEmpty()? "a" : s;
            return this;
        }
        
        private KAKAOID noGreaterThan16() {
            s = (s.length()>15)? s.substring(0,15) : s;
            s = s.replaceAll("[.]$", "");
            return this;
        }
        
        private KAKAOID noLessThan2() {
            StringBuilder sBuilder = new StringBuilder(s);
            while(sBuilder.length()<=2) {
                sBuilder = sBuilder.append(sBuilder.charAt(sBuilder.length()-1));
            }
            s = sBuilder.toString();
            return this;
        }
        
        
 
        public String getResult() {
            return s;
        }
 
        
    }
        
}

 

 

출처 :  https://techhan.github.io/algorithm/programmers-40/