Multiple language literals cannot be accessed

[a3li]

In my ontology, have no assurance that the prefLabels have languages:

:thing1  skos:prefLabel
    "Thing" .

:thing2  skos:prefLabel
    "Thing"@en ;
    "Ding"@de .

So I'm trying to create a "LabelledModel" that can work with either:

@RdfProperty(value="skos:prefLabel", language="")
protected String skosPrefLabel;
@RdfProperty(value="skos:prefLabel", language="de")
protected String skosPrefLabelDE;
@RdfProperty(value="skos:prefLabel", language="en")
protected String skosPrefLabelEN;

Currently, RdfGenerator.fromRDF maintains the aAccessMap as PropertyURI -> Field 1:1 mapping. The way I understand the problem, I can only have one field linked to a property, whereas to capture the different language literals, I need multiple.

The current code threw exceptions trying to cast a String to a Collection?!
I tried to fix this in a3li/Empire@2f3723d
As I'm digging really deep into the core, I'd appreciate some comments before submitting a pull request.

[mhgrove]

Yes, the expectation originally was a 1:1 mapping from field unless specified otherwise via an annotation. Your commit seems ok, but I think there are cases where you don't know all the language tags you are interested in a priori. In those cases, you probably want all of them (on the bean), and a way at runtime to get a specific version w/ a given language.

So it might be the case that the normal behavior is fine, but that there is a new 'primitive' LanguageString which under the hood is a collection, but has a toString(final String theLanguage) method to get the string w/ the appropriate language. That might work for both use cases.

[a3li]

Sounds good as well.
Can you implement that 'primitive' or if not, give me a few hints on how to do it?

[mhgrove]

I can, but it won't be any time soon. If you need it in the near future, I'd recommend doing it yourself.

It should be pretty straightforward. ToObjectFunction handles, generally, RDF -> Java. Give the property->field mapping, it gets all the values for that property, so you have Collection<Value> and when the field is a Collection will turn that into a Collection<Object>

When the field is not a Collection, it tries to see if it's a list of literals, and if LANG_AWARE is enabled, it removes all literals which are not tagged w/ the correct language, otherwise, it removes all literals with a language tag.

It's probably there that you might put in the logic to do something smarter w/ the conversion of the list of lang-tagged literals.

ValueToObject mostly handles direct conversion of RDF Value -> Object, so it's possible something might go there, but you can probably get away with only modifying ToObjectFunction

The opposite conversion is easier, you'd just need an else if (LanguageString.class.isAssignableFrrom(aValue.class)) in RdfGenerator#asRdf(Object) and convert the object into the appropriate number of statements there.