generics + new = problem
HI All,
This problem is not new, I read a lot, but I still do not understand
if there's a solution or not (shame on me).
The problem is: I want to build a generic class that constructs new
instances of the type variable.
i.e.:
public interface IOCElement extends Serializable, ChangeEmitter {
public String getName();
}
public class GenericListModel<T extends IOCElement> extends
AbstractListModel
implements ComboBoxModel, ChangeListener {
static final long serialVersionUID = 1l;
private ArrayList<T> tList = null;
public GenericListModel() {
tList = new ArrayList<T>();
}
// AbstractListModel implementation
public Object getElementAt(int index) { return tList.get(index); }
public int getSize() { return tList.size(); }
// needed for FreeMarker
public ArrayList<T> getTasks() { return tList; }
// ComboBoxModel implementation
transient private int selectedItem = -1;
public Object getSelectedItem() { return (selectedItem>=0)?
get(selectedItem): null; }
public void setSelectedItem(Object anItem) { if (anItem instanceof
IOCElement) { selectedItem = pos(((IOCElement)anItem).getName()); } }
// API
public T get(int index) { return tList.get(index); }
public int add(String name) {
int index = 0;
if (tList.add(new T(name))) {
index = tList.size();
tList.get(index-1).addChangeListener(this);
selectedItem = -1;
fireIntervalAdded(this, index, index);
}
return index-1;
}
..... etc. etc.
Everything is ok BUT the line that reads:
if (tList.add(new T(name))) {
I understand that erasures make this difficult for the compiler, but:
Is there a way around this (possibly using newInstance(),
constructor() or whatever)?
Can someone tell me exactly what I should do? (if anything can be
done).
Thanks in Advance
Mauro