Version 7.16.0

Minor release: a substantially better Java generator, and a round of fixes to the generated web app driven by running a full acceptance suite against it. The Java work was contributed by Klausmp and palfner-sse (BESSER #595, #596) and reviewed and completed by the BESSER team. The rest came out of driving the Agentic-Low-Code-Benchmark hotel-booking suite through the generated interface, which surfaced a set of defects that only appear once an application is actually used.

One change can reject a model that was previously accepted: a class may no longer declare a method with the name of one of its attributes or association ends. See Model validation below.

Highlights

  • Java generator: enumerations are generated as Java enum files and used as the type of the attributes, parameters and return values that reference them; bidirectional associations emit a field on both sides; navigability is honoured, so a non-navigable end no longer produces a field; methods declared in the model are emitted as stubs; and the package name is now an explicit package_name parameter of JavaGenerator rather than being guessed from the output path. Method stubs throw UnsupportedOperationException so the generated sources compile whatever a method returns, and the test suite now compiles its output with javac when a JDK is available.

  • A 0..1 association end is a single object again: relationships are assigned after the class body, so SQLAlchemy never sees the Mapped_ annotation and inferred a collection from the foreign-key direction. An optional end read back as [] rather than None, which made a guard as ordinary as if self.invoice is not None always true — a booking could never produce its bill.

  • Association ends keep the names the diagram gives them: an association class exposed only its link rows, so self.rooms — the end name the model uses, and the one its own OCL constraints navigate — raised AttributeError at runtime. The ends are now reachable under their model names as read-only views over the link table, with writes still going through the association class.

  • A class’s methods are on the class: model methods existed only as bodies inlined into the endpoints exposing them, so a method calling another method of the same object failed on an object that, per the diagram, has it.

  • An optional association-class attribute stays optional: the link payload declared every attribute of the association class as required whatever the model said, so the request the form built was rejected for a value the interface never asked for.

  • A declined method is no longer reported as a success: a method that guards itself — refusing a second bill, a departure before arrival — reports that by returning false, and the page announced “Operation completed successfully” all the same. The confirmation is withheld and the result popup names the outcome.

  • Lookup options identify the record: the attribute shown for a related record preferred one literally named name, so two guests called Jane were indistinguishable in a dropdown. An attribute the model marks as a business identifier now wins, an email outranks a name, and every multi-select option carries the key of the record it stands for.

Model validation

DomainModel.validate() reports a method that shares its name with an attribute or an association end of the same class. Generated code reaches both through that one name, so one wins and the other becomes unreachable: a body reading self.check_out - self.check_in subtracted two methods instead of two dates, and the failure surfaced at runtime with nothing pointing back to the diagram. A model that does this now fails validation and has to rename one of the two.

Other fixes

  • The standalone web app tool (besser.utilities.web_modeling_editor.backend.tools.generate_web_app_from_json) reads the project export the editor writes today. A project keeps a list of diagrams per type and names the active one in currentDiagramIndices, which the generation router already honoured; the tool still expected a single diagram per type and failed on every current export.

  • The generated create form preselects the default values declared on the attributes, so an enumeration with a default arrives selected instead of empty.