| AbstractEditPart>>refreshChildren bug? [message #185972] |
Thu, 30 June 2005 22:31  |
 Emerson Murphy-Hill
Messages: 22
Registered: July 2009 |
Junior Member |
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Howdy Y'all,
This appears to be a bug to me, but I could easily be doing something
wrong. I have had a problem where, when I delete a node from a
container, some other element in the container gets deleted. Bad. I
think I have tracked down the problem...
The scenario:
I have a subclass of AbstractGraphicalEditPart that redefines
getChildren() and returns a new List every time (this is necessary
because I return a typed list, using covariance). Now
AbstractEditPart>>refreshChildren looks something like this:
protected void refreshChildren() {
...
List children = getChildren();
...
if (editPart != null)
reorderChild (editPart, i);
...
List trash = new ArrayList();
for (; i < children.size(); i++)
trash.add(children.get(i));
for (i = 0; i < trash.size(); i++) {
EditPart ep = (EditPart)trash.get(i);
removeChild(ep);
...
}
The problem is, reorderChild does the reordering on the children
*field*, which happens to reorder the children *local variable* iff the
two reference the same object. In my case, they do not, since
getChildren() returns a new List. When this happens, the wrong EditPart
gets added to the trash.
So I hope this makes sense. Am I right in thinking this is a bug?
Thanks!
e
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| Re: AbstractEditPart>>refreshChildren bug? [message #186005 is a reply to message #185972] |
Fri, 01 July 2005 02:13  |
Dazhen Gao
Messages: 21
Registered: July 2009 |
Junior Member |
|
|
I think the other element don't gets deleted.See layoutmanager of the
contend pane.Debuge the layout method, I guess the fit the wrong position.
Above is my guess.
"Emerson" <emerson@cs.pdx.edu> wrote in message
news:da1rnq$l5u$1@main1.eclipse.org...
> Howdy Y'all,
>
> This appears to be a bug to me, but I could easily be doing something
> wrong. I have had a problem where, when I delete a node from a container,
> some other element in the container gets deleted. Bad. I think I have
> tracked down the problem...
>
> The scenario:
>
> I have a subclass of AbstractGraphicalEditPart that redefines
> getChildren() and returns a new List every time (this is necessary because
> I return a typed list, using covariance). Now
> AbstractEditPart>>refreshChildren looks something like this:
>
> protected void refreshChildren() {
> ...
> List children = getChildren();
> ...
> if (editPart != null)
> reorderChild (editPart, i);
> ...
>
> List trash = new ArrayList();
> for (; i < children.size(); i++)
> trash.add(children.get(i));
> for (i = 0; i < trash.size(); i++) {
> EditPart ep = (EditPart)trash.get(i);
> removeChild(ep);
> ...
> }
>
> The problem is, reorderChild does the reordering on the children *field*,
> which happens to reorder the children *local variable* iff the two
> reference the same object. In my case, they do not, since getChildren()
> returns a new List. When this happens, the wrong EditPart gets added to
> the trash.
>
> So I hope this makes sense. Am I right in thinking this is a bug?
>
> Thanks!
>
> e
|
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| Re: AbstractEditPart>>refreshChildren bug? [message #186106 is a reply to message #186072] |
Fri, 01 July 2005 18:00 |
Emerson Murphy-Hill
Messages: 22
Registered: July 2009 |
Junior Member |
|
|
I think you are correct and your suggestion is a good strategy.
However, the reason for overriding getChildren() is because my EditPart
contains generic children. So My EditPart looks something like:
MyEditPart<ChildPartType extends EditPart>
extends GraphicalAbstractEditPart {
....
protected List<ChildPartType> getChildren(){
...//call super, and cast all children
}
....
}
From my perspective, in order to make up for the fact that EditPart is
not generic (yet!), this is a perfectly reasonable thing to do.
So I think my point still stands.
-e
Andreas Holtz wrote:
>
> You should always use getModelChildren() and let GEF creates (via your
> EditPartFactory) and order the corresponding Editparts. If you do it
> your way, you are responsible for the consistency between the children
> of your model and the children of your editpart.
> If you delete an editpart, you should not do this within your
> editpart-list, but within your model.
> the editparts should listen on changes on the model and refresh
> themselves when neccesary.
>
> Andreas
>
> PS: i hope, i did not tell you something, that you already know. but i
> don't understand, why you overwrite getChildren().
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