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[jwt-dev] support for multiple views

Hi all,


as announced, I’d like to start with the implementation of the new view mechanism during the next days. Since there still seems to be some discussion related to the final requirements of the features that should be supported in the end I’m going to start with a (hopefully) less controversial part of the implementation that can be done mostly independent from the rest of the views: The support for different positions in different views.

This feature will be very important once we have views like swimlanes which will give elements positions and dimensions that cannot be shared with “conventional” views and therefore this information cannot be shared between different views. Also, the user may want to arrange elements in a more business oriented view in a different manner than in a technical view (which often contains much more elements and may require more space between the elements). Therefore, the model should be able to store one position/dimension for each model element and each view.


The proposed implementation consists of:


- Removing Point and Dimension from the View package

- Adding a ViewData element to the View Package with attributes viewID, x, y, width, height

- Removing Location(Point) and Size(Dimension) from the GraphicalElement

- Adding ViewData as 0..* relationship to the GraphicalElement

- Adjusting the code, so the information in the ViewData element that corresponds to the current view is used

- Sourcing out the storage of these elements into a new file (e.g. *.workflowview) to prevent the core model file (*.workflow) from being cluttered with view-specific information

- Other view specific information (like References and ReferenceEdges) should also be put into this file


However, there are a few complications:


- This modification will cause incompatibility with the old file format (as will do any modification of the metamodel which makes it imcompatible with the previous one). We’ll need to implement transformations that convert the old files to the new format (Florian is already looking into this)

- If a view is used the first time, a dialog should be displayed to let the user import the initial positions for the elements from another view or use an automatic layouting algorithm

- It would probably also be nice if the positions of elements can be synchronized between different views, so that if the user moves an element in View1, it gets moved automatically to the same position in View2 (basically an emulation of what we have now, which will be still useful in some cases I guess)


As always, if someone has some suggestions or objections to this proposal, please do not hesitate to answer.