I have mostly completed the work. I still have to add code to handle exceptions and do some extensive testing.
Using the web app, one can now attach a PDI transformation to a project. The app will analyze if a rule engine step is in the transformation. In case there are multiple rule engine steps, the user can select which one to use.
Now, when the user writes rules or actions, he/she no longer needs to type in the field names and the field types manually but the fields are selectable from a dropdown. This is easier for the user and avoids typos or wrong field type selections.
And there are some minor features that I want to implement. E.g. a check that is run before exporting the project file if all rules are consistant.
The code, database schema and a war file is available on http://github/uwegeercken