Hi Phil,
Glad you got it working - emails with "SOLVED" in the title are always
nice to see!
Presumably, you are a snapshot build of Jena. Readers should all work
now and if your HTTP library messes up the reader from the HTTP response
inc charset I'd be very surprised but it does presume that the response
is complete and valid. HTTP has too many moving parts with "some
assembly required".
Andy
On 16/11/13 01:15, Phillip Rhodes wrote:
Andy, that works now, using the StringReader. Thank you very much
for the rapid reaction to this. It is greatly appreciated.
I will revisit reworking this to use an InputStream eventually, due to the
character encoding issues, but this helps me get a prototype out
quickly, given that
Groovy's RestClient gives me back a String instance when I request JSON, and the
most obvious way to bridge that into jena (when I first started
looking) appeared to be
using the StringReader. I guess I could have turned that into a
ByteArrayInputStream
had a I realized what was going on sooner. Oh well, live and learn.
Thanks again for the help, and - more generally - for all your work on Jena.
Phil
On Fri, Nov 15, 2013 at 8:42 AM, Phillip Rhodes
<[email protected]> wrote:
Ah, OK. I'll give that a try then. Thanks for the heads-up.
Phil
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On Fri, Nov 15, 2013 at 4:01 AM, Andy Seaborne <[email protected]> wrote:
On 15/11/13 05:59, Phillip Rhodes wrote:
FWIW... I just grabbed the Jena source, imported it into my workspace
and set my project to reference that, so I could debug into this as
it's running. What I see is the code getting to line 864 in RDFDataMgr
and executing this code:
parser = RiotReader.createParser(tokenizer, lang, base, output) ;
which returns null. The next line tries to use the null reference,
and hence the NPE.
Looking at RiotReader.createParser(), I don't see anything in there
that mentions JSON-LD at all. But the docs for java-jsonld say
something like:
"JenaJSONLD must be initialized so that the readers and writers are
registered with Jena." and I do call the init() method. But I don't
see how that registration process plays with this createParser() code.
I'm guessing things have just gotten out of sync between Jena and the
JSON-LD stuff?
The problem is reading from a reader (I should have noticed this earlier in
the thread).
If you use an InputStream it will work (= it does for me).
Readers are troublesome because they fix the charset before Jena gets a
chance set the encodign according to syntax. A FileReader is particularly
troublesome because it fixes the charset as the system default so if that is
not UTF-8 (and it isn't on Windows) it will not be UTF-8.
StringReader is only usecase but it currently follows a hardwired path
inside RDFDataMgr. The general ReaderRIOT interface does not have Readers.
Regrettably, I think I'll have to go and add Readers to ReaderRIOT (it only
results in parallel code - InputStream and Reader have no commonality) just
because of StringReader.
You should be able to pass the input stream from HTTP request to the
RDFDataMgr or model.read directly.
Andy
Phil
