Java Ceaser Cipher

Cypher.java

/**
 * -------------------------------------------
 * File name: Cypher.java
 * Project Name: Ceaser Cipher
 * Created By: Mackenly Jones
 * Date: 4/12/22
 * -------------------------------------------
 */

package CeaserCipher;

/**
 * Class Name: Cypher 
 * Purpose: Defines a Caesar cypher class
 * Date: Apr 12, 2022
 */
public class Cypher {

    // Instance Variables
    // Cypher key:
    private int cypher;

    // Parameterized Constructor
    public Cypher(int cypher) {
        this.cypher = cypher;
    }

    // Getters
    public int getCypherKey() {
        return this.cypher;
    }

    // Encrypt Method
    /**
     * doEncryption
     * Encrypts a string using the cypher key
     *      (doesn't support non-alphabetical values)
     *      (only supports the lower or upper case English alphabet)
     *      (unsupported characters are ignored)
     * @param s String to be encrypted
     * @return String encrypted
     */
    public String doEncryption(String s) {
        String s1 = "";
        // Loop through the string and perform the encryption
        for (int i = 0; i < s.length(); i++) {
            // Grab the character
            char c = s.charAt(i);
            // Find out if it's uppercase or lowercase
            // Chars represent numbers in ASCII, so we can do math on them
            // By offsetting the character by the cypher we can effectively shift the character
            if (Character.isUpperCase(c)) {
                c = (char) (c + this.cypher);
                // If we go past 'Z' we need to wrap around to 'A'
                if (c > 'Z') {
                    // There are 26 letters in the English alphabet
                    c = (char) (c - 26);
                }
            } else if (Character.isLowerCase(c)) {
                c = (char) (c + this.cypher);
                // If we go past 'z' we need to wrap around to 'a'
                if (c > 'z') {
                    // There are 26 letters in the English alphabet
                    c = (char) (c - 26);
                }
            }
            // Append the result to the output string
            s1 += c;
        }
        return s1;
    }

    // Decryption Method
    /**
     * doDecryption
     * Decrypts a string using the cypher key
     *      (doesn't support non-alphabetical values)
     *      (only supports the lower or upper case English alphabet)
     *      (unsupported characters are ignored)
     * @param s String to be decrypted
     * @return String decrypted
     */
    public String doDecryption(String s) {
        String s2 = "";
        // Loop through the string and perform the decryption
        for (int i = 0; i < s.length(); i++) {
            // Grab the character
            char c = s.charAt(i);
            // Find out if it's uppercase or lowercase
            // Chars represent numbers in ASCII, so we can do math on them
            // By offsetting the character by the cypher we can effectively shift the character using numbers
            if (Character.isUpperCase(c)) {
                c = (char) (c - this.cypher);
                // If we go past 'A' we need to wrap around to 'Z'
                if (c < 'A') {
                    // There are 26 letters in the English alphabet
                    c = (char) (c + 26);
                }
            } else if (Character.isLowerCase(c)) {
                c = (char) (c - this.cypher);
                // If we go past 'a' we need to wrap around to 'z'
                if (c < 'a') {
                    // There are 26 letters in the English alphabet
                    c = (char) (c + 26);
                }
            }
            // Append the result to the output string
            s2 += c;
        }
        return s2;
    }
}

Demo.java

/**
 * -------------------------------------------
 * File name: Demo.java
 * Project Name: Ceaser Cipher 
 * Created By: Mackenly Jones
 * Date: 4/12/22
 * -------------------------------------------
 */

package CeaserCipher;

import java.util.Scanner;

/**
 * Class Name: MyCypherDemo 
 * Purpose: Test the MyCypher class
 * Date: Apr 12, 2022
 */
public class CypherDemo {

    public static void main(String[] args) {
        //start code here:
        // Declare variables
        String input = "", encrypted = "", decrypted = "";

        // Print welcome message
        printWelcomeSignature("Mackenly Jones", "Problem 2", "CypherDemo");

        // Ask user for input
        input = inputHelper("Enter the input string: ");

        // Create a new cypher object
        Cypher cypher = new Cypher(13);

        // Print the encrypted string
        encrypted = cypher.doEncryption(input);
        System.out.println("Print the encrypted string: " + encrypted);

        // Print the decrypted string
        decrypted = cypher.doDecryption(encrypted);
        System.out.println("\nPrint the decrypted string: " + decrypted);

    } //end main

    /**
     * Method Name: printWelcomeSignature
     * Method Description: Takes some arguments and formats them into a welcome message and prints it
     * @param programmerName programmer to show up in message
     * @param problemName course name to show up in message
     * @param fileName project name to show in message
     * @author Mackenly Jones
     */
    public static void printWelcomeSignature(String programmerName, String problemName, String fileName) {
        int neededLen = 2 + programmerName.length() + 3 + problemName.length() + 3 + fileName.length() + 2;
        String topBorder = "/";
        String bottomBorder = "\\";
        for (int i = 0; i < neededLen; i++) {
            topBorder += "-";
            bottomBorder += "-";
        }
        topBorder = topBorder + "\\";
        bottomBorder = bottomBorder + "/";
        System.out.println(topBorder + "\n" + "|  " + programmerName + " - " + problemName + " - " + fileName + "  |" + "\n" + bottomBorder + "\n\n");
    }

    /**
     * inputHelper
     * Shows user a prompt and gets a string from the user
     * @param prompt - prompt to display to user
     * @return - returns the user's input
     */
    public static String inputHelper(String prompt) {
        System.out.print(prompt);
        Scanner input = new Scanner(System.in);
        return input.nextLine();
    }
}