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Asynchronous updates of Edges [message #1724340]

Tue, 23 February 2016 04:27

Eclipse User

I've create a JFace based ZestViewer based on domain objects for nodes and edges which are being displayed as expected. I'm using my own LabelProvider etc etc.

What I fail to understand is how changes in the domain objects arriving asynchronously from a background thread are supposed to be visualized in the graph viewer.

I've studied the behavior framework and checked the post about dynamic graph attributes but these use-cases change visuals based on actions from within the gef4 framework.

The behavior monitors the various selection/content/hide models but I can't see a subscription mechanisme between the MVC (content) model and the JFace content provider.

viewer.getAdapter(ContentModel.class).getContents().setAll(Collections.singletonList(createRootGraph(getContentProvider(), getLabelProvider())));

The line above shows how domain objects delivered by the domain specific content provider is being used to populate the graph/viewer with nodes and edges. Once this is done it looks to me that changes in the domain objects can not be detected except for calling a complete refresh which causes also a layout.

Looking at how hiding works I've tried to add a complete set of 'EdgeStatusBehavior'/Operation/Policy to support edge status changes but now I can't traverse back to the domain objects because I only have references to the ContentModel etc. The obvious solution would be to introduce something like a EdgeStatusModel but this would result in duplication of state which I don't think is the way forward.

I'm a bit lost at present: Perhaps someone can push me in the right direction.

Thanks in advance.

[Updated on: Wed, 24 February 2016 02:23] by Moderator

Re: Asynchronous updates of Edges [message #1725601 is a reply to message #1724340]

Fri, 04 March 2016 13:23

Eclipse User

Hi Johan,

the API is only designed for a complete refresh as the ZestContentViewer is lacking update methods for individual elements. Do you have ideas for a good API? If so, please open a Bugzilla. I will also think about this over the weekend.

Best regards,
Matthias

Re: Asynchronous updates of Edges [message #1731305 is a reply to message #1725601]

Wed, 04 May 2016 04:30

Eclipse User

Hey!
I think that I am facing a related problem. See https://www.eclipse.org/forums/index.php/t/1076280/

My issue is that I want to update the color of edges. This works in the case that refresh() is called on the viewer object, but as you mentioned this will also call complete Layout (which is in my case not inteded).
In the meantime I've tried to implement a workaround. The idea is to maintain a map storing the visuals for all edges (of type EdgeContentPart) in the current styleprovider and implementing a factory like behavior for the styleprovider aswell.
Same I did for for the nodes(NodeContentPart) and this works great. Sad thing is that this workaround works for nodes but not for edges since I am not able to get the current reference to the used color. I don't know how the EdgeAttributeMap is used by the styleProvider to influence this workaround.

If you have found n way to archive update behavior on edges please let me know.

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