On 03/10/14 10:07, Wetz Peter wrote:
Andy, thanks for your suggestions again and thanks for pointing to the other
threads in order to have some sort of consistent access to my questions ;)
You could take the source code and change this (it's a trivial change) to add a
new format that is triples+time.
this sounds interesting to me. could you elaborate on that? with "add a new
format" do you mean a new serialization format in jena, i.e., a class like
LANG.NQUADS? Or do you mean something else?
I'd be glad if you could provide pointers on how to add a new format, i.e.,
triples+time.
Have a look at NQUADS - the parser is LangNQuads (actually LangNTuple),
Lang/RDFLanguages for contants and RDFParserRegistry/RDFWriterRegistry
for registration.
That will get you some machinery. I still think there is a bigger
question for you. Adding a time component to a triples is outside RDF
and indeed the "RDF way" is different (model the events, not the triples).
Access and manipulation of triples+time is going to be unnatural in a
pure RDF viewpoint by overloading the fourth field of a quad.
Andy
Thanks and best,
Peter
-----Ursprüngliche Nachricht-----
Von: Andy Seaborne [mailto:a...@apache.org]
Gesendet: Donnerstag, 02. Oktober 2014 22:54
An: users@jena.apache.org
Betreff: Re: AW: RDF Streaming timestamp annotated triples/quads in Jena:
Create a Quadruple in Jena and store it as a file, or outputstream
On 02/10/14 08:39, Wetz Peter wrote:
Thanks for your response and the pointers. I will definitely have a closer
look and am happy to mutually share advances in this area.
Meanwhile I could solve my technical and intial problem of storing a
quad in Jena. It's important to write the quad in a format which
supports quads, obviously. So one should use, e.g., N-QUADs. See below.
N-Quads requires a URI or bnode as the graph name. There are limits as to
how far the code will work when you go outside standard RDF.
You could take the source code and change this (it's a trivial change) to add a
new format that is triples+time. Or use Michel's suggestion, or use named
graphs and provenance about the graph.
My answer at:
http://answers.semanticweb.com/questions/30509/how-to-write-a-quad-
into-a-jena-graph-and-then-to-file
also comments on:
http://stackoverflow.com/questions/26145412/how-to-write-a-quad-into-a-
jena-graph-and-then-to-file
Andy
The running code looks like this:
DatasetGraph dsg = DatasetGraphFactory.createMem(); Triple e1 = new
Triple(subject, predicate, object); Quad quad1 = new Quad(timestamp,
e1); dsg.add(quad1); //and then write it into an output stream
OutputStream output; output = new
FileOutputStream("c:\\output-text.nq");
RDFDataMgr.write(output, dsg, Lang.NQ);
hth
best,
Peter
-----Ursprüngliche Nachricht-----
Von: Bohms, H.M. (Michel) [mailto:michel.bo...@tno.nl]
Gesendet: Donnerstag, 02. Oktober 2014 09:30
An: users@jena.apache.org
Cc: theo.riesw...@priva.nl; Taal, J. (Johan);
miguel.ol...@telvent.com; miguel.ol...@telvent.com; Leandro Madrazo
Agudin
Betreff: RE: RDF Streaming timestamp annotated triples/quads in Jena:
Create a Quadruple in Jena and store it as a file, or outputstream
Dear Peter,
Thanks for this very interesting info on streaming rdf, never heard
about it before.
In a running eu project (odysseus) we develop ontologies that deal
with dynamic properties (energy-related measurements by sensors etc.
in buildings and districts) involving time series, interval values,
units, time stamps etc. I included some ontology (depc)/dataset
(examples). Clearly having my worries wrt performance in case of
bigdata sets..so any base support on meta-level would help I guess...
In depc we use units (of QUDT) as underlying types for the properties.
We also dev. in parallel a more class-based approach
(http://vps16544.public.cloudvps.com/xwiki/bin/view/4.+VCON+Experimen
t
al+CBNL+MG+Extension/WebHome)
Where property instances can have more (meta-)info like unit, but in
future more value-info like timestamp/interval (unless of course
built-in on higher level like via RSP...
So, sorry not to be able to answer your question, but guess we share
a similar interest...
Greetings, Michel
Dr. ir. H.M. (Michel) Bohms
Sr. Research Scientist
Structural Reliability
T +31 (0)88 866 31 07
M +31 (0)63 038 12 20
E michel.bo...@tno.nl
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-----Original Message-----
From: Wetz Peter [mailto:peter.w...@tuwien.ac.at]
Sent: donderdag 2 oktober 2014 8:19
To: users@jena.apache.org
Subject: RDF Streaming timestamp annotated triples/quads in Jena:
Create a Quadruple in Jena and store it as a file, or outputstream
With Jena I want to create a quadruple to create triples + a
timestamp to store so called "streaming RDF data", which is an
upcoming area of interest in both research and industry.
For reference please see the RSP (RDF Stream Processing) Community
group over at the W3C which recently formed to eventually work out a
W3C Recommendation Draft on this topic: [1]. In their wiki they
define RDF streams as "streams consisting of RDF elements [...]
annotated by a minimum of one timestamp or interval." [2]
So, all I want to do is to be able to store a quadruple, i.e., a
Subject - Predicate - Object relation + a Timestamp. In one
implementation of such a RDF Stream Processor they are simply doing it
like this:
RdfQuadruple q = new RdfQuadruple(subject, predicate, object,
timestamp);
My question is, how this can be done similarly in Jena?
I thought about "abusing" the quad-feature for this. Yes, quads
actually are a feature for storing triples in named graphs, but I thought
about "abusing"
quads by just using a timestamp for the graph-node-parameter. I dont
know if this approach scales, but I just wanted to give it a try.
However, I am not able to get a running example. I can create a quad,
but then don't know how to store this in a DatasetGraph and writing it
into a file.
If someone could provide a running example of creating a quad +
storing it in a file, this would be highly appreciated. More
generally, if someone has a better idea to store quadruples, i.e.,
time annotated RDF triples, I am also happy to hear from you.
Best regards,
Peter
[1] http://www.w3.org/community/rsp/
[2]
http://www.w3.org/community/rsp/wiki/Concepts_and_Definitions#Scope
_of_the_Community_Group
