Fix #628: implement hierarchical keywords

[tobiasdiez]

The automatic keywords group now supports hierarchical keywords.
The changes mainly concentrate on the keywords class...so this may have some unwanted side effects in other parts (but I didn't noticed anything unusual in my tests).

Note: Bib files containing an automatic keyword from prior 4.0 tests can no longer be opened and the lines containing AutomaticKeywordGroup have to be deleted.

• Change in CHANGELOG.md described
• Tests created for changes
• Screenshots added (for bigger UI changes)
• Manually tested changed features in running JabRef
• Check documentation status (Issue created for outdated help page at help.jabref.org?)
• If you changed the localization: Did you run gradle localizationUpdate?

[lenhard]

Not really using keywords I cannot meaningfully test this and someone else should jump in for that. The code looks good mostly except for some architecture thing: Do we really want the model to be depending on JavaFX classes? I vaguely remember discussing this and maybe I was overruled by the majority. If so, please point me to where this is documented. If not, please change your code :-)

[lenhard]

I know this is convenient, but I am strongly against it. We do not want the model to be dependent on a GUI technology. If you want this conversion to be done based on ObservableList, it will have to be done elsewhere.

[tobiasdiez]

I agree that we don't want to have GUI technology in our model and logic classes. However, these observable lists and properties have nothing to do with the GUI-related part of JavaFX - you can use them in a command line application if you want. An observable list is just a list with some built-in event listeners, i.e. a different form of List combined with the google event stuff. Similar the properties in in javafx.beans are just fields with event handlers.

Thus I strongly vote for allowing javafx.collections and beans in model and logic.

[lenhard]

Decision in devcall: make exception for javafx.collections.*

[lenhard]

Again, no javafx in model

[matthiasgeiger]

Note: Bib files containing an automatic keyword from prior 4.0 tests can no longer be opened and the lines containing AutomaticKeywordGroup have to be deleted.

Isn't there a possibility to migrate this? From a user point of view this is not really acceptable...

[tobiasdiez]

@matthiasgeiger I formulated it a bit awkwardly. Automatic keywords groups are a new feature in 4.0, so this only hits users of the current development version - not users of 3.8.2.