Can't pass the last condition.

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I cannot pass the last condition. I get NullPointerException when I run the verification. I suppose that I haven't done everything correctly in the controller: public void onShowAllUsers(){ model.loadUsers(); usersView.refresh(model.getDataModel()); } Can someone please help?

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; import com.codegym.task.task36.task3608.bean.User; import com.codegym.task.task36.task3608.model.FakeModel; import com.codegym.task.task36.task3608.controller.Controller; import com.codegym.task.task36.task3608.view.View; import com.codegym.task.task36.task3608.view.UsersView; import com.codegym.task.task36.task3608.dao.mock.DataSource; import com.codegym.task.task36.task3608.model.Model; import com.codegym.task.task36.task3608.model.DataModel; import java.lang.NullPointerException; public class Solution { private UsersView usersView; public void setUsersView(UsersView usersView){ this.usersView = usersView; } public static void main(String[] args) throws NullPointerException { UsersView usersView = new UsersView(); usersView.fireShowAllUsersEvent(); } }

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Guadalupe Gagnon

Level 37 , Tampa, United States

27 April 2020, 15:13

useful

First, in the Usersview class get rid of line 10. Now the problems that you are experiencing come from following the code. In main a UserView object is created and calls fireShowAllUsersEvent(). If you go to the UserView class and look at that method it calls controller.onShowAllUsers();. At this point in the code 'controller' has not been set and will throw a null point exception. Furthermore, if you go to the Controller class you will see onShowAllUsers() calls 2 lines:

model.loadUsers();
usersView.refresh(model.getDataModel());

Both of these will throw null pointer exceptions if called before the variables model and usersView have been set. To fix this, in main: 1) You will want to create a controller and use it to set the corresponding field in the userView object and then 2) create a Model (FakeModel for this part of the task) and use it and the userView object to set each in the controller class. After these you should be able to do call usersView.fireShowAllUsersEvent(); and get the proper results.

Branka

Level 41 , Belgrade, Serbia

27 April 2020, 16:36

Thank you, thank you, thank you! It worked. I couldn't have done it without your hints. This one was really hard for me.

Guadalupe Gagnon

Level 37 , Tampa, United States

27 April 2020, 17:25

No problem, I still have your other questions saved to take a longer look at later.