SimpleCrypt/Crypto/src/ROT13.java

import static java.lang.Character.isLowerCase;
import static java.lang.Character.isUpperCase;
import static java.lang.Character.toLowerCase;

public class ROT13  {

    Character cs;
    Character cf;

    ROT13(Character cs, Character cf) {
        this.cs= cs;
        this.cf=cf;
    }

    ROT13() {
        this.cs='a';
        this.cf='m';
    }


    public String crypt(String text) throws UnsupportedOperationException {
      return encrypt(encrypt(text));
    }

    public String encrypt(String text) {
        String result = "";
        int rotator = cf-cs;
        boolean isUppercase = false;
        for(int i=0; i<text.length(); i++){
            isUppercase = Character.isUpperCase(text.charAt(i));
            int temp = Character.toLowerCase(text.charAt(i));
            if (temp<97|temp>122){
            } else if(temp+rotator < 122){
            temp = (int)text.charAt(i)+rotator;
            } else {
                temp = 96 + ((temp+rotator)-122);
            }
            if(isUppercase){temp=Character.toUpperCase(temp);}
            result+= (char)temp;
        }
        return result;
    }

    public String decrypt(String text) {

        String result = "";
        int rotator = cf-cs;
        boolean isUppercase = false;
        for(int i=0; i<text.length(); i++){
            isUppercase = Character.isUpperCase(text.charAt(i));
            int temp = Character.toLowerCase(text.charAt(i));
            if (temp<97|temp>122){
            } else if(temp-rotator > 97){
                temp = (int)text.charAt(i)-rotator;
            } else {
                temp = 122 - (96-(temp-rotator));
            }
            if(isUppercase){temp=Character.toUpperCase(temp);}
            result+= (char)temp;
        }
        return result;
    }

    public static String rotate(String s, Character c) {
        String result = "";
        String reference = s+s;
        int rotator = Character.toLowerCase(c)-'a';
        boolean isUppercase = false;
        for(int i=0; i<s.length(); i++){
          Character temp = reference.charAt(i+rotator);
            result+= temp;
        }
        return result;
    }

}