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Notifications for bidirectional references [message #129929]

Thu, 02 October 2008 02:25

chengdong

Messages: 17
Registered: July 2009

Junior Member

Case:

class A{
EList<B> links;
}

class B{
EList<A> revLinks;
}

The links and revLinks are set as bidirectional references.

The problem happens in following code:
1 A a;
2 B b1, b2;
3 ... call factory to create a and b1, b2 ...
4 a.getLinks().add(b1);
5 a.getLinks().add(b2);

There is inconsistency for line 4 and line5:
line 4: only fire 1 ViewerNotification for adding b1 to a
line 5: fire 2 ViewerNotifications for adding a to b1.revLinks and
adding b1 to a.links

Can someone explain this to me why there is different behavior in line 4
and 5? Is this a bug in EMF?

Thanks

-chengdong

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Re: Notifications for bidirectional references [message #129941 is a reply to message #129929]

Thu, 02 October 2008 12:10

Ed Merks

Messages: 33140
Registered: July 2009

Senior Member

This is a multi-part message in MIME format.
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Chengdong,

This is really an EMF question. Please use the EMF newsgroup next time.
<news://new.eclipse.org/eclipse.tools.emf>

news://new.eclipse.org/eclipse.tools.emf

chengdong wrote:
> Case:
> class A{
> EList<B> links;
> }
>
> class B{
> EList<A> revLinks;
> }
>
> The links and revLinks are set as bidirectional references.
>
> The problem happens in following code:
> 1 A a;
> 2 B b1, b2;
> 3 ... call factory to create a and b1, b2 ...
> 4 a.getLinks().add(b1);
> 5 a.getLinks().add(b2);
>
> There is inconsistency for line 4 and line5:
> line 4: only fire 1 ViewerNotification for adding b1 to a
> line 5: fire 2 ViewerNotifications for adding a to b1.revLinks and
> adding b1 to a.links
>
> Can someone explain this to me why there is different behavior in line
> 4 and 5? Is this a bug in EMF?
I don't really see how 5 affects b1 at all. In general, whether a
viewer notification is fired will depend on whether there's an adapter
attached to the b objects. If the b objects are new objects, they
likely don't have an adapter attached to them yet because nothing was
viewing them yet...
>
> Thanks
>
> -chengdong
>

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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html;charset=ISO-8859-15"
http-equiv="Content-Type">
</head>
<body bgcolor="#ffffff" text="#000000">
Chengdong,<br>
<br>
This is really an EMF question.

Ed Merks
Professional Support: https://www.macromodeling.com/

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