Week 5: Class hierarchies/06. Class gradebook

Write a category 'Gradebook' with the following properties
Attribute owner of type string
Attribute grades, whose type is a list. The list must be able to store objects of type Grade (the class can be found in the attached program)
A constructor that takes the owner as a parameter and sets the value of the attribute. The constructor also initializes the grade list.
The attributes must be 'protected' so that the client cannot see them, but any inheriting classes can.


import java.util.Random;
import java.lang.reflect.Field;
import java.util.ArrayList;

public class Test{
    public static void main(String[] args){
        final Random r = new Random();
        
        
        System.out.println("Testing class Gradebook...");
        Gradebook gb = new Gradebook("Gary Grader");
        
        System.out.println("Object created!");
        
        try {
            Field number = gb.getClass().getDeclaredField("owner");
            boolean numberPrivate = number.getModifiers() == 4;
            System.out.println("Owner is protected: " + numberPrivate);
        } catch (Exception e) {
            System.out.println("Attribute owner is not defined");
        }
        
        try {
            Field grades = gb.getClass().getDeclaredField("grades");
            boolean asPrivate = grades.getModifiers() == 4;
            System.out.println("Grades is protected: " + asPrivate);
            
            ArrayList<Grade> as = gb.grades;
            boolean isInitialized = gb != null;
            System.out.println("Grades is initialized: " + isInitialized);
        } catch (Exception e) {
            System.out.println("Attribute grades is not initialized");
        }
    }
}

class Grade {
    private String student;
    private int grade;
    
    public Grade(String student, int grade) {
        this.student = student;
        this.grade = grade;
    }

    public String getStudent() {
        return student;
    }

    public int getGrade() {
        return grade;
    }

}






//add
class Gradebook {
    protected String owner;
    protected ArrayList<Grade> grades;

    // constructor
    public Gradebook(String owner) {
        this.owner = owner;
        this.grades = new ArrayList<Grade>();
    }
}



Testing class Gradebook...
Object created!
Owner is protected: true
Grades is protected: true
Grades is initialized: true