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Question about the task

MVC (part 3)

Java Multithreading, Level 4, Lesson 14

Resolved

Where is the Mistake

To understand whether you're heading in the right direction, you need to see the data. Therefore,
1. In the view package, create a UsersView class that implements View. It will display the list of users.

2. Create a controller field, and a corresponding setter, in UsersView.

3. Implement the refresh method:
3.1. Display the phrase "All users:".
3.2. Display all of the users in dataModel.
Indent each user with a tab.
3.3. Display the following visual separator at the end
===================================================

4. I'm already interested in seeing what we've got.
Add to UsersView a public void fireShowAllUsersEvent() method that emulates a client event.
Access the controller and call the appropriate method to display all users.

5. The Solution class will emulate a user. Open the Solution class, go to the red method,
and use IDEA's hot keys to create a usersView property (field).
All you need is a setter. If you created a getter, delete it.

6. Run main. Oops, nothing is displayed :(
This is because the server sent the data, and it was updated in the DataModel, but the View doesn't know anything about it.
The View can't update itself. The Controller does that.
Go to the controller and update the View's data.
Remember, the data is stored in the Model.

7. Run main. I now have this output:
All users: User{name='A', id=1, level=1} User{name='B', id=2, level=1} ===================================================
Hooray! Let's keep going.

Requirements:

A UsersView class that implements the View interface must be created in the view package.
A private Controller controller field and corresponding setter must be created in the UsersView class.
The UsersView class's refresh method must be implemented according to the task conditions.
The UsersView class must have a public void fireShowAllUsersEvent() method that must call the onShowAllUsers() method on the controller.
A private UsersView usersView field and corresponding setter must be created in the Controller class. A getter must not be created for this field.
The userView object's refresh method must be called in the Controller class's onShowAllUsers() method with model.getDataModel() as the argument, after a call to the loadUsers() method.
Calling the main method must display information about each of the users that you added in the FakeModel class's loadUsers() method.

package com.codegym.task.task36.task3608.dao; import com.codegym.task.task36.task3608.bean.User; import com.codegym.task.task36.task3608.dao.mock.DataSource; import java.util.ArrayList; import java.util.List; public class UserDao { private DataSource dataSource = DataSource.getInstance(); public User getUserById(long id) { List<User> users = dataSource.getUsers(); for (User user : users) { if (user.getId() == id) { return user.clone(); } } return User.NULL_USER; } public List<User> getUsersByName(String name) { if (name == null || name.trim().isEmpty()) throw new IllegalArgumentException(); List<User> users = dataSource.getUsers(); List<User> result = new ArrayList<>(); for (User user : users) { if (name.equals(user.getName())) { addUserToResult(result, user); } } return result; } public List<User> getAllUsers() { List<User> users = dataSource.getUsers(); List<User> result = new ArrayList<>(); for (User user : users) { addUserToResult(result, user); } return result; } public List<User> getUsersByLevel(int level) { if (level < 1) throw new IllegalArgumentException(); List<User> users = dataSource.getUsers(); List<User> result = new ArrayList<>(); for (User user : users) { if (level == user.getLevel()) { addUserToResult(result, user); } } return result; } public void addUserToResult(List<User> result, User user) { User clone = user.clone(); // Skip invalid users if (clone != User.NULL_USER) { result.add(clone); } } public User createOrUpdate(User user) { return dataSource.createOrUpdate(user); } public User getUsersById(long userId) { if (userId < 1) throw new IllegalArgumentException(); List<User> users = dataSource.getUsers(); for (User user : users) { if (userId == user.getId()) { return user; } } return User.NULL_USER; } }

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Satya Vath

Level 31 , Vijayawada, India

24 May 2019, 10:07

Thanks EveryOne

Azja

Level 32 , Krakow, Poland

24 May 2019, 09:44

solution

Check if you have Solution class in your project. If no search "javarush.task" or something like that (should be somewhere under your project) and look for "javarush.task.3608 it might be different and there is solution class(click to get bigger)

Copy this to project folder, delete unused imports and insert imports from current project

Djole

Level 41 , Belgrade, Serbia

24 May 2019, 08:51

useful

did you add usersView.fireShowAllUsersEvent(); in Solution class?