Hi Andy,
I get the exact same output (I'm running the latest code from the repo).
The way I understand the output is that it basically is a nameless graph
which *contains* the 3 named graphs described in the N-Quads, isn't it?
I agree, it is correct JSONLD-wise since the spec says you have to have one
default/nameless graph and zero to many named graphs (not sure why a
nameless default graph is required).
My question was whether we could have had the default nameless graph not as
a container to the named graphs? Maybe that does not make any sense, but I
was thinking maybe something like:
[
{ "@graph": {}},
{ "@graph": {},
"@id": "graph1"},
{ "@graph": {},
"@id": "graph2"},
{ "@graph": {},
"@id": "graph3"}
]
Thanks for your help,
Hubert
On Thu, May 22, 2014 at 11:19 AM, Andy Seaborne <[email protected]> wrote:
> On 22/05/14 18:04, Hubert Le Van Gong wrote:
>
>> I'm using whatever default setting there is.
>> How do I check this?
>>
>
> It's not the default.
>
> Exactly what are you seeing? I have run your example data (NQ) and get
> the quads only once.
>
> Code below: output:
>
> {
> "@graph" : [ {
>
> "@graph" : [ {
> "@id" : "_:b0",
> "http://an.example/predicate1"; : "object1"
> } ],
>
> "@id" : "http://example.org/graph1";
> }, {
> "@graph" : [ {
> "@id" : "_:b1",
> "http://an.example/predicate2"; : "object2"
> } ],
>
> "@id" : "http://example.org/graph2";
> }, {
> "@graph" : [ {
> "@id" : "http://one.example/subject3";,
> "http://one.example/predicate3"; : {
> "@id" : "http://one.example/object3";
> }
> } ],
> "@id" : "http://example.org/graph3";
> } ]
> }
>
> which isn't ideal pretty but is correct. "object1", "object2" and
> "object3" occur only once.
>
>
> "@graph" : [ {
>
> "@graph" : [ {
> "@id" : "_:b0",
> "http://an.example/predicate1"; : "object1"
>
> } ],
> "@id" : "http://example.org/graph1";
> },
> ...
> is a single named graph as written by jsonld-java.
> The inner "@graph" and "@id" are members of the same JSON {}-object.
>
> Andy
>
> PS Which version of Jena are you using?
> My example is from latest dev, jsonld-java v0.4
> The current snapshot artifacts are now up-to-date.
>
>
> package dev ;
>
> import java.io.ByteArrayInputStream ;
> import java.io.ByteArrayOutputStream ;
>
> import org.apache.jena.atlas.logging.LogCtl ;
> import org.apache.jena.riot.Lang ;
> import org.apache.jena.riot.RDFDataMgr ;
>
> import com.hp.hpl.jena.query.* ;
> import com.hp.hpl.jena.tdb.TDBFactory ;
>
> public class DevMain
> {
> static {
> LogCtl.setLog4j() ;
> }
>
> public static void main(String... argv) throws Exception {
> Dataset ds = TDBFactory.createDataset() ;
> RDFDataMgr.read(ds, "D.nq") ;
> ByteArrayOutputStream bout = new ByteArrayOutputStream() ;
> RDFDataMgr.write(bout, ds, Lang.JSONLD) ;
> bout.flush() ;
> RDFDataMgr.write(System.out, ds, Lang.JSONLD) ;
>
> ByteArrayInputStream bin = new
> ByteArrayInputStream(bout.toByteArray())
> ;
> Dataset ds1 = DatasetFactory.createMem() ;
> RDFDataMgr.read(ds1, bin, null, Lang.JSONLD) ;
> RDFDataMgr.write(System.out, ds1, Lang.TRIG) ;
> System.exit(0) ;
>
> }
>
>
>
>
>> Thanks,
>> Hubert
>>
>>
>>
>> On Thu, May 22, 2014 at 9:50 AM, Andy Seaborne <[email protected]> wrote:
>>
>> Do you have TDB defaultUnionGraph turned on?
>>>
>>> On 22 May 2014 16:51, Hubert Le Van Gong <[email protected]> wrote:
>>>
>>>> Cool, it worked fine.
>>>>
>>>> Just curious, I noticed that the named graphs end up embedded in the
>>>> required default (nameless) graph (see below).
>>>> Any particular reason to do this and not have the default graph empty,
>>>> followed by the named graphs?
>>>>
>>>> Cheers,
>>>> Hubert
>>>>
>>>> {
>>>> "@graph" :
>>>> [
>>>> {
>>>> "@graph" :
>>>> [...],
>>>> "@id" : "http://example.org/graph1";
>>>> },
>>>> {
>>>> "@graph" :
>>>> [...],
>>>> "@id" : "http://example.org/graph2";
>>>> },
>>>> ]
>>>> }
>>>>
>>>>
>>>> On Thu, May 22, 2014 at 4:16 AM, Andy Seaborne <[email protected]> wrote:
>>>>
>>>> On 22/05/14 03:03, Hubert Le Van Gong wrote:
>>>>>
>>>>> Greetings,
>>>>>>
>>>>>> I have a set of N-Quad statements that relate to different graphs. How
>>>>>>
>>>>> do
>>>
>>>> I
>>>>>> go about exporting all those statements into a single JSON-LD object?
>>>>>>
>>>>>> For instance, I would expect that something like:
>>>>>> <http://one.example/subject3> <http://one.example/predicate3> <
>>>>>> http://one.example/object3> <http://example.org/graph3> .
>>>>>> _:subject1 <http://an.example/predicate1> "object1" <
>>>>>> http://example.org/graph1> .
>>>>>> _:subject2 <http://an.example/predicate2> "object2" <
>>>>>> http://example.org/graph2> .
>>>>>>
>>>>>> would end up as the following JSON-LD (disclaimer: I'm not 100% sure
>>>>>>
>>>>> this
>>>
>>>> is correct, JSON-LD wise):
>>>>>>
>>>>>> [
>>>>>> {
>>>>>> "@context": {
>>>>>> "predicate3": "http://one.example/predicate3";
>>>>>> },
>>>>>> "@id": "http://example.org/graph3";,
>>>>>> "@graph":
>>>>>> [
>>>>>> {
>>>>>> "@id": "http://one.example/subject3";,
>>>>>> "predicate3": "http://one.example/object3";
>>>>>> }
>>>>>> ]
>>>>>> },
>>>>>> {
>>>>>> "@context": {
>>>>>> "predicate1": "http://an.example/predicate1";
>>>>>> },
>>>>>> "@id": "http://example.org/graph1";,
>>>>>> "@graph":
>>>>>> [
>>>>>> {
>>>>>> "@id": "_:b0",
>>>>>> "predicate1": "object1"
>>>>>> }
>>>>>> ]
>>>>>> },
>>>>>> {
>>>>>> "@context": {
>>>>>> "predicate2": "http://an.example/predicate2";
>>>>>> },
>>>>>> "@id": "http://example.org/graph2";,
>>>>>> "@graph":
>>>>>> [
>>>>>> {
>>>>>> "@id": "_:b0",
>>>>>> "predicate2": "object2"
>>>>>> }
>>>>>> ]
>>>>>> }
>>>>>> ]
>>>>>>
>>>>>>
>>>>>> So far, the approach I took was to load the n-quads using:
>>>>>> RDFDataMgr.read(dataset, in, RDFLanguages.NQUADS);
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>> and then iterate through the graph names, to get each model with:
>>>>>> Model model = dataset.getNamedModel(name);
>>>>>>
>>>>>> Something like model.write(out, RDFLanguages.strLangJSONLD); works
>>>>>>
>>>>> well to
>>>
>>>> convert the data to JSON-LD, however it does not add any graph info
>>>>>> (@graph).
>>>>>> While I could probably stitch those parts together, I was hoping for a
>>>>>> cleaner way to do this.
>>>>>>
>>>>>>
>>>>> If you write the whole dataset:
>>>>>
>>>>> RDFDataMgr.write(System.out, dataset, Lang.JSONLD) ;
>>>>>
>>>>> all the graphs will come out, named.
>>>>>
>>>>> If you want to print one graph, with it's name, create a separate
>>>>>
>>>> dataset,
>>>
>>>> put just that graph in it, as a named graph, and print that.
>>>>>
>>>>> Models don't have names - it's the container (dataset) that gives it
>>>>>
>>>> it's
>>>
>>>> name. It can have several names (be included several times, or in
>>>>>
>>>> several
>>>
>>>> places).
>>>>>
>>>>> Andy
>>>>>
>>>>>
>>>>>
>>>>> In particular, I tried to create a new model by uniting 2 models at a
>>>>>>
>>>>> time
>>>
>>>> but it did not quite work (although I do see @graph added)...
>>>>>>
>>>>>> Can anyone shed some light on the best approach for this?
>>>>>>
>>>>>> Cheers,
>>>>>> Hubert
>>>>>>
>>>>>> PS: my apologies if it's already been discussed before but I did not
>>>>>>
>>>>> find
>>>
>>>> anything on this particular topic in the list archive.
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>
>>
>
