Question

I’m trying to create a generic container which has a copy-constructor. I’m having trouble using the clone method even though I have coded it in. Here’s what I have so far:

public class MyBox<T> 
{
    private List<T> list;

    public MyBox()
    {
        list = new ArrayList<T>();
    }


    public void add(T item )
    {
        list.add(item);
    }

    public MyBox(MyBox<T> other) throws CloneNotSupportedException //this is giving me trouble
    {
        for(T item : other.list)
        {
            list.add((T) item.clone());
        }
    }
}

How can I get my copy-constructor to work?

Answer 1

Usually you don’t need to clone the item.

public MyBox(MyBox<T> other)
{
    list = new ArrayList<T>(other.list);
}

When you add an item from collection A to collection B, the item is now referenced by both two collection A and B.