On 11/05/15 20:28, Martynas Jusevičius wrote:
Thanks Andy.
I have a parser that works on String, but this time I want to do it
right and make it streaming and plug it into Jena at the low level.
It seems that I should be able to reuse some code from TokenizerText.
I understand StreamRDF is used to sink the triples, but what about
ParserProfile? I see LangTurtleBase uses it:
org.apache.jena.iri.IRI iri = profile.makeIRI(iriStr,
currLine, currCol) ;
How do I construct an instance of ParserProfile? Or is there an
alternative way to construct IRIs etc.?
RiotLib.profile
Andy
Martynas
On Mon, May 11, 2015 at 2:44 PM, Andy Seaborne <a...@apache.org> wrote:
On 10/05/15 21:48, Martynas Jusevičius wrote:
Hey all,
I want to refactor my RDF/POST parser into a Jena-compatible reader.
An example of the format can be found here:
http://www.lsrn.org/semweb/rdfpost.html#sec-examples
The documentation suggests implementing ReaderRIOT interface:
https://github.com/apache/jena/blob/master/jena-arq/src-examples/arq/examples/riot/ExRIOT_5.java
However, if I look at (what I think is) existing readers such as
Turtle for example, they do not seem to implement ReaderRIOT:
https://github.com/apache/jena/blob/master/jena-arq/src/main/java/org/apache/jena/riot/lang/LangTurtleBase.java
What is the explanation for that?
Hi Martynas,
It is historical - the Turtle derived parsers emerged with the RiotReader
interface and some code is/was around that used that interface.
ReaderRIOTLang is the cross-over code from the proper interface ReaderRIOT
to RiotReader. RiotReader is a fixed set of parsers.
This can be sorted out in Jena3.
Do I need to to tokenize the InputStream myself or is there some
machinery I can reuse?
The Turtle-world tokenizer is TokenizerText. It is turtle term specific.
Any tokenizing for a new language is often, in my experience, very sensitive
to the language details.
If you are used to javacc, and performance isn't critical at scale, that's a
good tool.
RIOT uses custom I/O for speed; Jena used to have a javacc parser for Turtle
but Turtle is sufficiently simple that a hand-written parser is doable. A
hand written tokenizer is for speed at scale (big file - about x2 than basic
javacc tokenizing) but you need large input to make it worthwhile. NTriples
dumps of databases make it worthwhile.
If you do rdfpost -> Turtle (string manipulation), then you can parse the
Turtle as normal. Downside: Error messages may be confusing as they refer
to the Turtle, not the input string.
Splitting up the query string, with all the HTTP escaping rules, can be done
with library code (see FusekiLib.parseQueryString [no longer used, but it
works without consuming the body, unlike the servlet operations which
combine form and query string processing] and probably lots of better code
examples on the web.
Andy
Martynas
graphityhq.com
