Addon options for editing graphic models of dot language?

I am building a web application for use as a model based performance testing tool. This tool uses the
dot graphic description language
for generating the models. the functional requirements include to be able to create and edit these models not only by uploading dot language settings, but graphically manipulating the graph as well.

Any ideas for the best way vaadin might be able to handle this task based on the existing capabilities and add-ons?

Matti Tahvonen’s diagram builder (
https://vaadin.com/directory#addon/diagram-builder
) seems like it could perhaps accomplish this task? In this case it would require formatting the json output back and forth, so if drag and drop changes are made to the graph, then parse the json output into a format to be saved as in dot language; and when textual changes are made to a dot file, format that to the way the add-on writes the diagram?

Any ideas are welcome. If this addon would be the most appropriate or maybe I have not seen something that would work better?

Thank you!

Hi,
I need something like this, have you find a solution?

I am so far ending up using the above mentioned diagrambuilder addon. I needed to customize some functionality to suit my use case but for the most part this does the trick.