Thread: ArrayList as a parameter

I have five classes all together: Instructor, Student, Course, Section, and Testing.

In the section class, I have this:

public class Section {
    private Course course;
    private Instructor instructor;
    private ArrayList<Student> students;
 
    public Section() {
        super();
    }
 
    public Section(Course course) {
 
    }
 
    public Section(Course course, Instructor instructor) {
 
    }
 
    public Section(Course course, Instructor instructor, ArrayList<Student> students) {
 
    }
      // getters and setters
 
    public void setCourse(Course course)
      {
        this.course = course;
      }
 
    public Course getCourse()
      {
        return course;
      }
 
    public void setInstructor(Instructor instructor)
      {
        this.instructor = instructor;
      }
 
    public Instructor getInstructor()
      {
        return instructor;
      }
 
    public void setStudents(ArrayList<Student> students)
      {
        this.students = students;
      }
 
    public ArrayList<Student> getStudents()
      {
        return students;
      }
 
    public void addStudent(Student student)
      {
        students.add(student);  // add a student to the section roster
      }  
    }

In the main method, I want to create a Section object by accessing this constructor from the Section class:

public Section(Course course, Instructor instructor, ArrayList<Student> students) {
 
}

So I started with:

public class Testing01 {
    public static void main (String [] args) throws IOException {
 
        Section sec = new Section("Java Programming", "George Jones", /* ArrayList variable here*/); {
 
}
}
}

I would like the constructor to create the ArrayList, but I can not figure out how to code the parameter. It's not in my reading and I have scoured the Internet for the answer with no results. I really want to comprehend this, so can anyone walk me through this? I would be most appreciative.

Originally Posted by Norm

What class is the constructor in? The Testing01 class does not have a constructor.
What parameter does the constructor need to have to create the ArrayList?


Are you asking how to pass a variable to a constructor? Put the name inside the ()s
TheClass tc = new TheClass(theVariable);

I might be using the wrong words. I have the constructor in the Section class:

public Section(Course course, Instructor instructor, ArrayList<Student> students) {
 
    }

Am I missing information in the constructor? Is there supposed to be information in between the brackets?

Originally Posted by helloworld922

Creating an ArrayList isn't much different from creating any other object (you're already creating a Section object). Just pick a constructor and call new Constructor(params). Available ArrayList constructors: JavaDoc - ArrayList.


ex. ArrayList constructor with no parameters

new ArrayList<Student>()

Am I not able to use the constructor in the Section class to create the ArrayList variable?