Converting to/from JSON-LD

[imsdu]

Version

5.6.0

Feature

Since #3061 and #3501 , converting to and from JSON-LD is done via the RdfQuadConsumer from Titanium.

My problem is that those conversions are now contained in classes also responsible for reading and writing files when I would like to be able do those transformations in-memory (it was possible with JenaTitanium in the previous implementation).

Could the new conversion implementation be placed to a dedicated class to address my use case or are there strong arguments against it ?

Are you interested in contributing a solution yourself?

Yes

[rvesse]

This feels like an XY problem, though that may just be that the way you've phrased your question isn't sufficiently detailed/clear enough for me to understand what you are trying to achieve

My problem is that those conversions are now contained in classes also responsible for reading and writing files when I would like to be able do those transformations in-memory

Are you asking whether you can take a Jena Graph/DatasetGraph and obtain the JSON-LD as an in-memory string? And vice-versa?

If yes, then yes you can.

For the write path just pass in a ByteArrayOutputStream as the OutputStream to the writer APIs and then convert the byte[] back to a UTF-8 string i.e. new String(output.toByteArray(), StandardCharsets.UTF_8) as needed.

Similarly for the read-path Jena allows for providing input data as a string, or arbitrary InputStream implementation e.g. ByteArrayInputStream, as needed.

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If you are trying to do something else then you need to explain this more clearly, preferably with an example of what you did on previous Jena versions that you want to achieve with the current version

[imsdu]

Hello,
When converting between a Jena DatasetGraph and its JSON-LD representation, I want to get a JSON object to continue to work on it.
Same when converting between JSON-LD to a DatasetGraph, I am expecting a DatasetGraph.

I can do it through streams and get a string as you proposed and parse it back but it adds unnecessary complexity.
Note that what I would like was possible in 5.2: https://github.com/apache/jena/blob/jena-5.2.0/jena-arq/src/main/java/org/apache/jena/riot/system/JenaTitanium.java .

I hope it is a bit clearer :).

[afs]

The JenaTitanium.convert() operations? i.e. the public operations from JenaTitanium?

It is not a simple matter of digging that code out of git. The problem is that Titanium's com.apicatalog.rdf.RdfDataset is marked for removal.

`titanium-json-ld' 1.7.0+ is now a JSON-LD parser and the algorithms from the JSON-LD spec.

There is a new repo titanium-rdf-primitives (which is not currently a Jena dependency).

The RdfDataset in titanium-rdf-primitives is not the same. There are classes that look like they provide the original functionality.

If you want to explore bringing in a new JenaTitanium which is future-proof that would be great.

If your use case is covered by the JSON-LD transformation algorithms, then it is a matter of exposing them in a Jena way, which is different, but would also be great to have.