Question

Homework 3: Input Validation

1   Objectives

• control structures
• console-based user input using Scanner class
• writing complete programs using two classes: client and supplier

2   User Interface Specification

This is a console-based I/O program. Display should go to System.out (print or println) and the program will get user input using the Scanner class. The flow of execution should be as follows:

• When the program starts, display a one-line introduction to the user
• Display a menu with 5 options

1. validate zip code

2. validate SSN

3. validate password

4. instructions

0. quit

• Prompt the user to input an option
• Prompt the user for the required input and then display the results
• Repeat the main menu until the user enters the option to quit
• If the user enters an invalid menu option, print a helpful error message and re-prompt. Note, this could be either a wrong value or wrong data type.

3   Code Specifications

For this assignment, you will write two different classes. The goal is to separate the user interface code from the code that performs validation. The sample programs MyMath.java and TestMyMath.java are an essential reference.

In a supplier class named Validations, implement 3 static methods to perform these different validation tasks:

• validate that a String represents a valid zip code. A valid zip code is made up of 5 digits.
• validate that a String represents a 9-digit SSN. A valid SSN follows the pattern XXX-XX-XXXX, including the dashes.
• validate that a String represents 8 symbols, including letters (upper and lower case), numbers, and special symbols like #$&_.

Though I specify 3 public methods, you may have more if you choose to do some decomposition. Note that this Validations class does not need a 'main' method. However, you may write one for testing purposes if you wish. You must use parameter lists and return statements to move data in and out of these methods. No method in this class should use System.out.println or the Scanner class (except an optional test method). In other words, no method here should interact with the user; that's the job of the other class.

In a class named ValidateApp, create a console-based, menu-driven user interface that behaves like the one described above. This class must use a 'main' method to start things off. However, you are encouraged to decompose your solution to organize your code.

No class variables may be used; class constants are ok.

Your program should not throw any exceptions to the user. If a user enters an invalid menu option, the program should display a helpful error message and ask for new input.

You must implement your solution using loops, if statements, and switch-case.

4   Testing & Documentation

• As always, I recommend doing this in pieces. For example, you might choose to do the validation code first (testing as you go). Then focus on the user interface.
• Your documentation in both classes is an integral part to your solution since you are the designer/author of these classes.
  • Each class should have an overall description comment at the top
  • Be sure to include a java-doc for each method that describes what it does, describes the parameters and the return.
  • Make sure to include internal comments to guide the reader through your algorithms.

5   File Submission

There are two different .java files for this assignment: Validations.java and ValidateApp.java. You will need to compress them into one .zip file, or use BlueJ to make a .jar file.

6   Grading

Area	Pct
Design, correctness, implementation	90%
Documentation and style	10%
Total	100%

Achievement	Max Points
Compile/runtime errors	50%
Basic objects	100%

Answer 1

Program

import java.util.Scanner;

class Validations{
   //for verifying zip code
   public boolean validateZipCode(String str) {
       if(str.length()==5 && isNumeric(str))
           return true;
       else
           return false;
   }
   //for verifying SSN
   public boolean validateSSN(String str) {
       str = str.replaceAll("-","");
      
       if(str.length()==9 && isNumeric(str))
           return true;
      
       return false;
   }
   //for verifying password
   public boolean validatePassword(String str) {
       if(str.length()==8)
           return true;
       else
           return false;
   }
   //for checking the given string is number or not
   private static boolean isNumeric(String str) {
       try {
           Integer.parseInt(str);
           return true;
       }
       catch(NumberFormatException e) {
           return false;
       }
   }
}

public class ValidateApp {
   public static void main(String[] args) {
       Scanner sc = new Scanner(System.in);
       Validations obj = new Validations();
       String str, choice;
      
       System.out.println("**************Greeting User welcome to validation app**************");
       System.out.println();
       while(true) {//infinte loop
          
           System.out.println("1. validate zip code");
           System.out.println("2. validate SSN");
           System.out.println("3. validate password");
           System.out.println("4. instructions");
           System.out.println("0. quit");
           System.out.println();
          
           System.out.print("Enter your choice: "); choice = sc.nextLine();
           System.out.println();
          
           //switch case for handling user choice
           switch(choice) {
          
           case "0":
               System.out.println("Thank you for using this app");
               System.exit(0);
              
           case "1":
               System.out.print("Enter pin code: "); str = sc.nextLine();
               System.out.println();
               if(obj.validateZipCode(str))
                   System.out.println("The zip code "+str+" is valid");
               else
                   System.out.println("The zip code "+str+" is invalid");
              
               System.out.println();
               break;
              
           case "2":
               System.out.print("Enter SSN: "); str = sc.nextLine();
               System.out.println();
               if(obj.validateSSN(str))
                   System.out.println("The SSN "+str+" is valid");
               else
                   System.out.println("The SSN "+str+" is invalid");
              
               System.out.println();
               break;
              
           case "3":
               System.out.print("Enter password: "); str = sc.nextLine();
               System.out.println();
               if(obj.validatePassword(str))
                   System.out.println("The password "+str+" is valid");
               else
                   System.out.println("The password "+str+" is invalid");
              
               System.out.println();
               break;
              
           case "4":
               System.out.println("pin code is of 5 digits\n");
               System.out.println("SSN is of 9 digits\n");
               System.out.println("password is 8 symobols which include letters (upper and lower case), "
                       + "numbers, and special symbols like #$&_");          
               System.out.println();
               break;
              
           default://handling invalid user choice
               System.out.println("Invalid Input! Try Again");
               System.out.println();
               break;
           }
       }
   }
}

Output

<terminated> ValidateApp [Java Application] C\Program FilesJava\jre1.8.0_181binjavaw.exe (25-Apr-2019, 1:25:14 PM 1. validate zip code 2. validate SSN 3. validate password 4. instructions 0. quit Enter your choice: 1 Enter pin code: 12345 The zip code 12345 is valid 1. validate zip code 2. validate SSN 3. validate password 4. instructions 0. quit Enter your choice: 2 Enter SSN: 123-456-789 The SSN 123-456-789 is valid 1. validate zip code 2. validate SSN 3. validate password 4. instructions 0. quit Enter your choice: 0 Thank you for using this app