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physicsboy
physicsboy

Reputation: 6316

Take set of enums in a constructor and create list - Java

I am wanting to create a new student and instantiate them with a list of subjects that they are signed up for, but am unaware if it is possible or how to accomplish it?

I have initially put an ArrayList in the constructor, but I am certain that this is wrong.

The eventual outcome is that I have a student with Name, ID and an editable list of subjects that they are studying so that they can be added to and taken out of courses as and when...

Student.java

private String name;
private int id;
private static int counter;
private ArrayList<Subjects> subjects;

public Student(String name, ArrayList<Subjects> subjects) {
    this.name = name;
    this.subjects = subjects;
    counter++;
    id=counter;
}

School.java

  public class School {

    List<Student> students = new ArrayList<>();

    public void addStudent(String name, ArrayList<Subjects> subjects) {
        Student tempStudent = new Student(name,subjects);
        students.add(tempStudent);
    }
}

Run.java where my problems come...

 public class Run {

    public static void main(String[] args) {
        School school = new School();

        school.addStudent("ABC", Subjects.English.toString().......... );
    }
}

Subjects.java

public enum Subjects {
    Maths,
    English,
    Science
}

Upvotes: 1

Views: 333

Answers (2)

Maurice Perry
Maurice Perry

Reputation: 9651

Here's what I would do:

private String name;
private int id;
private static int counter;
private List<Subjects> subjects;

public Student(String name, Collection<Subjects> subjects) {
    this.name = name;
    this.subjects = new ArrayList<>(subjects);
    counter++;
    id=counter;
}

// second constructor for convenience
public Student(String name, Subjects... subjects) {
    this(name, Arrays.asList(subjects));
}

...

public class School {
    List<Student> students = new ArrayList<>();

    public void addStudent(String name, List<Subjects> subjects) {
        Student tempStudent = new Student(name,subjects);
        students.add(tempStudent);
    }

    public void addStudent(String name, Subjects... subjects) {
        Student tempStudent = new Student(name,subjects);
        students.add(tempStudent);
    }
}

Upvotes: 1

Murat Karag&#246;z
Murat Karag&#246;z

Reputation: 37584

You are no creating an Array nor adding an Enum. Change your Student class and every method associated with it to take a List and not an ArrayList e.g.

private List<Subjects> subjects;

Then you could use

 school.addStudent("ABC", Arrays.asList(Subjects.Maths, Subjects.English));

Upvotes: 2

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