<Swing Dev> 6179357: Generics: JList: getSelectedValues

[Florian Brunner]

So, does  everybody agree?

Would be great to also have opinions from someone working at Sun?

Pavel, especially your opinion is quite important since you will probably be 
the one who will have to eventually accept and commit my patch. :-)

-Florian

Am Dienstag, 30. Dezember 2008 schrieb Jonathan Giles:
> Florian,
>
> Your proposed solution of deprecating the old method and referring to
> the new method seems like a good idea to me.
>
> Cheers,
> Jonathan Giles
>
> Florian Brunner wrote:
> > Hi,
> >
> > I hope you all had a Merry Christmas! I started now to add generics to
> > ListModel and JList. While adding generics to the ListModel is quite
> > straightforward, I think, there are some issues with JList, I would
> > like to dicuss. I start here with the first issue: getSelectedValues
> >
> > Am I right, that there is no way to change the signature of this
> > method to:
> >
> > public E[] getSelectedValues()
> >
> > where E is the type parameter of the class?
> >
> > (Because of generic array creation, which is not supported by Java.)
> >
> > Here is the current implementation:
> >
> > public Object[] getSelectedValues() {
> >
> > ListSelectionModel sm = getSelectionModel();
> >
> > ListModel dm = getModel();
> >
> > int iMin = sm.getMinSelectionIndex();
> >
> > int iMax = sm.getMaxSelectionIndex();
> >
> > if ((iMin < 0) || (iMax < 0)) {
> >
> > return new Object[0];
> >
> > }
> >
> > Object[] rvTmp = new Object[1+ (iMax - iMin)];
> >
> > int n = 0;
> >
> > for(int i = iMin; i <= iMax; i++) {
> >
> > if (sm.isSelectedIndex(i)) {
> >
> > rvTmp[n++] = dm.getElementAt(i);
> >
> > }
> >
> > }
> >
> > Object[] rv = new Object[n];
> >
> > System.arraycopy(rvTmp, 0, rv, 0, n);
> >
> > return rv;
> >
> > }
> >
> > If this is not possible I propose to add a new method:
> >
> > public List<E> getSelectedItems()
> >
> > and deprecate getSelectedValues:
> >
> > ...
> >
> > * @deprecated As of JDK 1.7, replaced by {@link #getSelectedItems()}
> >
> > */
> >
> > @Deprecated
> >
> > public Object[] getSelectedValues() {
> >
> > ...
> >
> > }
> >
> > /**
> >
> > * Returns a list of all the selected items, in increasing order based
> >
> > * on their indices in the list.
> >
> > *
> >
> > * @return the selected items, or an empty list if nothing is selected
> >
> > * @see #isSelectedIndex
> >
> > * @see #getModel
> >
> > * @see #addListSelectionListener
> >
> > *
> >
> > * @since 1.7
> >
> > */
> >
> > public List<E> getSelectedItems() {
> >
> > ListSelectionModel sm = getSelectionModel();
> >
> > ListModel<? extends E> dm = getModel();
> >
> > int iMin = sm.getMinSelectionIndex();
> >
> > int iMax = sm.getMaxSelectionIndex();
> >
> > if ((iMin < 0) || (iMax < 0)) {
> >
> > return Collections.emptyList();
> >
> > }
> >
> > List<E> selectedItems = new ArrayList<E>();
> >
> > for(int i = iMin; i <= iMax; i++) {
> >
> > if (sm.isSelectedIndex(i)) {
> >
> > selectedItems.add(dm.getElementAt(i));
> >
> > }
> >
> > }
> >
> > return selectedItems;
> >
> > }
> >
> > Note: Ignore for now 'E' vs '? extends E', I will start another thread
> > for this. I'm just interested if you think it's a good idea to add the
> > getSelectedItems method and to deprecate getSelectedValues.
> >
> > So I wish you a Happy New Year and hope to hear from you soon.
> >
> > -Florian