anyone do question 2? please Create a class named UserAccounts that maintains a

Question

anyone do question 2? please

Create a class named UserAccounts that maintains a

list of user accounts, with an appropriate constructor,and the following methods:

isEmpty()returns true if list is empty, and false otherwise

findPassword - returns the password for a given user name

changePassword- updates the password for a given username and password. If they do not match password does not update

addUser- passed a user object to add

deleteUser- deletes a user for a given user name and password. If they do not match user is not deleted

printUsers- prints a list of all usernames, username and password

Explanation / Answer

Hello there ,

Please find below code and the output for the application .

=======

/**
* This is a User class containing username and password.
* @author dipal.prajapati
*
*/
public class User {
private String userName;
private String password;

public User(String userName, String password) {
   super();
   this.userName = userName;
   this.password = password;
}

public String getUserName() {
   return userName;
}

public void setUserName(String userName) {
   this.userName = userName;
}

public String getPassword() {
   return password;
}

public void setPassword(String password) {
   this.password = password;
}

@Override
public String toString() {
   return "User [userName=" + userName + ", password=" + password + "]";
}

@Override
public boolean equals(Object obj){
if( obj != null && obj.getClass().equals(this.getClass())){
return ((User)obj).toString().equals(this.toString());
} else {
return false;
}
}

}

=============

import java.util.ArrayList;
import java.util.List;

/**
* This is a class maintains list of Users and provide basic functionalities.
* @author dipal.prajapati
*
*/
public class UserAccounts {
   List<User> listOfUsers = new ArrayList<User>();

   /**
   * It checks if the list is empty.
   * @return
   */
   public boolean isEmpty() {
       return listOfUsers.isEmpty();
   }

   /**
   * It returns the password for a given user name
   * @param userName
   * @return
   */
   public String findPassword(String userName) {
       String password = null;
       for (User user : listOfUsers) {
           if (user.getUserName() != null
                   && user.getUserName().equals(userName)) {
               password = user.getPassword();
           }
       }
       return password;
   }

   /**
   * It updates the password for a given username and password. If they do not match password does not update.
   * @param user
   * @param newPassword
   */
   public void changePassword(User user, String newPassword) {
       if (listOfUsers.contains(user)) {
           for (User currentUser : listOfUsers) {
               if (currentUser.equals(user)) {
                   currentUser.setPassword(newPassword);
                   System.out.println("Password updated:"+newPassword);
               }
           }
       } else {
           System.out.println("Usename or Password does not match.");
       }
   }

   /**
   * It adds the user to the list.
   * @param user
   */
   public void addUser(User user) {
       listOfUsers.add(user);
       System.out.println(user.toString()+" added.");
   }

   /**
   * It deletes a user for a given user name and password. If they do not match user is not deleted.
   * @param user
   */
   public void deleteUser(User user) {
       listOfUsers.remove(user);
       System.out.println(user.toString()+" deleted.");
   }

   /**
   * It prints a list of all user name and password;
   */
   public void printUsers() {
       System.out.println(listOfUsers.toString());
   }

   public static void main(String args[]) {
       UserAccounts userAccounts = new UserAccounts();
       System.out.println(" Is UserList empty? " + userAccounts.isEmpty());
      
       System.out.println(" Add User/s:");
       userAccounts.addUser(new User("John", "abc"));
       userAccounts.addUser(new User("Tommy", "xyz"));
       userAccounts.addUser(new User("Lee", "pqr"));
      
       System.out.println(" Is UserList empty? " + userAccounts.isEmpty());
      
       System.out.println(" Find passwrod for John:"+userAccounts.findPassword("John"));
      
       User user= new User("John", "abc");
       System.out.println(" Change Password for John:");
       userAccounts.changePassword(user, "ABC");
      
       System.out.println(" Delete user Tommy:");
       user= new User("Tommy", "xyz");
       userAccounts.deleteUser(user);
      
       System.out.println(" Print all Users:");
       userAccounts.printUsers();
   }
}

========

Output on execution:

Is UserList empty? true

Add User/s:
User [userName=John, password=abc] added.
User [userName=Tommy, password=xyz] added.
User [userName=Lee, password=pqr] added.

Is UserList empty? false

Find passwrod for John:abc

Change Password for John:
Password updated:ABC

Delete user Tommy:
User [userName=Tommy, password=xyz] deleted.

Print all Users:
[User [userName=John, password=ABC], User [userName=Lee, password=pqr]]

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