Part I: Homework – please complete #5, Chapter 8 page 600. Java Book In this pro

Question

Part I: Homework – please complete #5, Chapter 8 page 600. Java Book

In this program, you will need to write your source code based on this UML for the PasswordVerifier.java, with the following attribute and members (private and public methods).

+ isValid(str : String) : boolean

-hasUpperCase(str : String) : boolean

-hasLowerCase(str : String) : boolean

-hasDigit(str : String) : boolean

Then write the PasswordDemo.java to verify the password is valid or invalid.

Please put all .java and .class files under Homework directory with screen shot of the PasswordDemo.class file below:

+ isValid(str : String) : boolean

-hasUpperCase(str : String) : boolean

-hasLowerCase(str : String) : boolean

-hasDigit(str : String) : boolean

Explanation / Answer

PasswordDemo.java

import java.util.Scanner;

public class PasswordDemo {

   public static void main(String[] args) {

       Scanner scan = new Scanner(System.in);
       System.out.println("Enter the password: ");
       String password = scan.next();
       if(PasswordVerifier.isValid(password)) {
           System.out.println("Given password is valid");
       }
       else {
           System.out.println("Given password is Invalid");
       }
   }

}

PasswordVerifier.java

public class PasswordVerifier {
   private static int MIN_PASSWORD_LENGHT = 6;
   public static boolean isValid(String str) {
       return str.length()>=MIN_PASSWORD_LENGHT && hasDigit(str) && hasUpperCase(str) && hasLowerCase(str);  
   }
   public static boolean hasUpperCase(String str) {
       for(int i=0; i<str.length(); i++){
           if(Character.isUpperCase(str.charAt(i))){
               return true;
           }
       }
       return false;
   }
   public static boolean hasLowerCase(String str) {
       for(int i=0; i<str.length(); i++){
           if(Character.isLowerCase(str.charAt(i))){
               return true;
           }
       }
       return false;
   }
   public static boolean hasDigit(String str) {
       for(int i=0; i<str.length(); i++){
           if(Character.isDigit(str.charAt(i))){
               return true;
           }
       }
       return false;
   }
}

Output:

Enter the password:
Password12!@
Given password is valid

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