public class CustomerListModel<T> extends AbstractListModel<T> implements ComboBoxModel<T> {

    private T[] values;
    private T selection;

    public CustomerListModel(T[] values) {
        super();
        this.values = values;
    }

    @Override
    public int getSize() {
        return values.length;
    }

    @Override
    public T getElementAt(int index) {
        return values[index];
    }

    @Override
    public void setSelectedItem(Object anItem) {
        selection = (T)  anItem;
    }

    @Override
    public T getSelectedItem() {
        return selection;
    }
}

    @Override
    public void setSelectedItem(T anItem) {
        String cl = anItem.getClass().getName();
        selection = (T)  anItem;
    }