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javardfjenasemantics

How to seperate one RDF model into two models in Jena?

Now I have a RDF data, which contain two resources(I don't know whether it is correct to call the staff in rdf:description a resource), Now I want to separate the two resource into two rdf data in Jena, I do not know how to use the API to do it, The data example:

<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:obs="http://localhost/SensorSchema/ontology#" > 
<rdf:Description rdf:about="http://localhost/SensorSchema/ontology#Observation_51709293_1_104519dd-63dc-4560-9286-8d621ce153c5">
    <obs:hasLatitude rdf:datatype="http://www.w3.org/2001/XMLSchema#double">65.00999166666666</obs:hasLatitude>
    <obs:hasDate rdf:datatype="http://www.w3.org/2001/XMLSchema#long">1365156000000</obs:hasDate>
    <obs:hasDirection rdf:datatype="http://www.w3.org/2001/XMLSchema#int">212</obs:hasDirection>
    <obs:hasVelocity rdf:datatype="http://www.w3.org/2001/XMLSchema#double">28.0</obs:hasVelocity>
    <obs:hasAcceleration rdf:datatype="http://www.w3.org/2001/XMLSchema#double">0.0</obs:hasAcceleration>
    <obs:hasLongitude rdf:datatype="http://www.w3.org/2001/XMLSchema#double">25.46780833333333</obs:hasLongitude>
    <obs:hasArea rdf:datatype="http://www.w3.org/2001/XMLSchema#int">38</obs:hasArea>
    <obs:hasDateTime>2013-04-05T13:00:00</obs:hasDateTime>
    <obs:hasSender rdf:datatype="http://www.w3.org/2001/XMLSchema#int">51709293</obs:hasSender>
    <rdf:type rdf:resource="http://localhost/SensorSchema/ontology#Observation"/>
    <obs:hasID rdf:datatype="http://www.w3.org/2001/XMLSchema#int">1</obs:hasID>
    <obs:hasDistance rdf:datatype="http://www.w3.org/2001/XMLSchema#double">0.0</obs:hasDistance>
</rdf:Description>
<rdf:Description rdf:about="http://localhost/SensorSchema/ontology#Observation_51709293_1_104519dd-63dc-4560-9286-8d621ce16666">
    <obs:hasLatitude rdf:datatype="http://www.w3.org/2001/XMLSchema#double">65.00999166666666</obs:hasLatitude>
    <obs:hasDate rdf:datatype="http://www.w3.org/2001/XMLSchema#long">1365156000000</obs:hasDate>
    <obs:hasDirection rdf:datatype="http://www.w3.org/2001/XMLSchema#int">500</obs:hasDirection>
    <obs:hasVelocity rdf:datatype="http://www.w3.org/2001/XMLSchema#double">28.0</obs:hasVelocity>
    <obs:hasAcceleration rdf:datatype="http://www.w3.org/2001/XMLSchema#double">0.0</obs:hasAcceleration>
    <obs:hasLongitude rdf:datatype="http://www.w3.org/2001/XMLSchema#double">25.46780833333333</obs:hasLongitude>
    <obs:hasArea rdf:datatype="http://www.w3.org/2001/XMLSchema#int">38</obs:hasArea>
    <obs:hasDateTime>2013-04-05T13:00:00</obs:hasDateTime>
    <obs:hasSender rdf:datatype="http://www.w3.org/2001/XMLSchema#int">51709293</obs:hasSender>
    <rdf:type rdf:resource="http://localhost/SensorSchema/ontology#Observation"/>
    <obs:hasID rdf:datatype="http://www.w3.org/2001/XMLSchema#int">1</obs:hasID>
    <obs:hasDistance rdf:datatype="http://www.w3.org/2001/XMLSchema#double">0.0</obs:hasDistance>
</rdf:Description>
</rdf:RDF>

I try to work like that:

ResIterator iter= OriginalModel.listSubjects();
int i=0;
    while(iter.hasNext()) {

        Resource subject = iter.next();
        Model[i].?? // add the whole resource
        i++;
}

but I don't know how to quickly add the resource to another model.

Solution

  • Once you have the subject, you can use listProperties to get a StmtIterator over the triples with that subject, and then you can use Model#add(StmtIterator) to add all those triples to a new Model.

    public void splitModels() throws IOException {
    // First, create a model and read the content 
    // into it.  You probably already have this part, 
    // but we need it for a working example.
    Model model = ModelFactory.createDefaultModel();
    try (InputStream in = SplitModelExample.class.getResourceAsStream("/example.rdf")) {
        RDFDataMgr.read(model, in, Lang.RDFXML);
    }

    // List the subjects in the model.
    ResIterator subjects = model.listSubjects();

    // For each subject, create another empty model that will 
    // contain the triples of which the subject is the subject.
    // The #listProperties() method returns a StmtIterator over
    // those triples, and Model#add(StmtIterator) adds all the
    // triples to a model.  Then we'll print out each submodel
    // to make sure we're getting what we expect.
    while (subjects.hasNext()) {
        Resource subject = subjects.next();
        Model subModel = ModelFactory.createDefaultModel();
        subModel.add(subject.listProperties());

        System.out.println("\n<!-- Submodel for "+subject+". -->");
        RDFDataMgr.write(System.out, subModel, Lang.RDFXML);
    }
}

    <!-- Submodel for http://localhost/SensorSchema/ontology#Observation_51709293_1_104519dd-63dc-4560-9286-8d621ce16666. -->
<rdf:RDF
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns:j.0="http://localhost/SensorSchema/ontology#">
  <j.0:Observation rdf:about="http://localhost/SensorSchema/ontology#Observation_51709293_1_104519dd-63dc-4560-9286-8d621ce16666">
    <j.0:hasLongitude rdf:datatype="http://www.w3.org/2001/XMLSchema#double"
    >25.46780833333333</j.0:hasLongitude>
    <j.0:hasLatitude rdf:datatype="http://www.w3.org/2001/XMLSchema#double"
    >65.00999166666666</j.0:hasLatitude>
    <j.0:hasVelocity rdf:datatype="http://www.w3.org/2001/XMLSchema#double"
    >28.0</j.0:hasVelocity>
    <j.0:hasID rdf:datatype="http://www.w3.org/2001/XMLSchema#int"
    >1</j.0:hasID>
    <j.0:hasDateTime>2013-04-05T13:00:00</j.0:hasDateTime>
    <j.0:hasDate rdf:datatype="http://www.w3.org/2001/XMLSchema#long"
    >1365156000000</j.0:hasDate>
    <j.0:hasDistance rdf:datatype="http://www.w3.org/2001/XMLSchema#double"
    >0.0</j.0:hasDistance>
    <j.0:hasSender rdf:datatype="http://www.w3.org/2001/XMLSchema#int"
    >51709293</j.0:hasSender>
    <j.0:hasAcceleration rdf:datatype="http://www.w3.org/2001/XMLSchema#double"
    >0.0</j.0:hasAcceleration>
    <j.0:hasArea rdf:datatype="http://www.w3.org/2001/XMLSchema#int"
    >38</j.0:hasArea>
    <j.0:hasDirection rdf:datatype="http://www.w3.org/2001/XMLSchema#int"
    >500</j.0:hasDirection>
  </j.0:Observation>
</rdf:RDF>


<!-- Submodel for http://localhost/SensorSchema/ontology#Observation_51709293_1_104519dd-63dc-4560-9286-8d621ce153c5. -->
<rdf:RDF
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns:j.0="http://localhost/SensorSchema/ontology#">
  <j.0:Observation rdf:about="http://localhost/SensorSchema/ontology#Observation_51709293_1_104519dd-63dc-4560-9286-8d621ce153c5">
    <j.0:hasLatitude rdf:datatype="http://www.w3.org/2001/XMLSchema#double"
    >65.00999166666666</j.0:hasLatitude>
    <j.0:hasDate rdf:datatype="http://www.w3.org/2001/XMLSchema#long"
    >1365156000000</j.0:hasDate>
    <j.0:hasDirection rdf:datatype="http://www.w3.org/2001/XMLSchema#int"
    >212</j.0:hasDirection>
    <j.0:hasVelocity rdf:datatype="http://www.w3.org/2001/XMLSchema#double"
    >28.0</j.0:hasVelocity>
    <j.0:hasAcceleration rdf:datatype="http://www.w3.org/2001/XMLSchema#double"
    >0.0</j.0:hasAcceleration>
    <j.0:hasLongitude rdf:datatype="http://www.w3.org/2001/XMLSchema#double"
    >25.46780833333333</j.0:hasLongitude>
    <j.0:hasArea rdf:datatype="http://www.w3.org/2001/XMLSchema#int"
    >38</j.0:hasArea>
    <j.0:hasDateTime>2013-04-05T13:00:00</j.0:hasDateTime>
    <j.0:hasSender rdf:datatype="http://www.w3.org/2001/XMLSchema#int"
    >51709293</j.0:hasSender>
    <j.0:hasID rdf:datatype="http://www.w3.org/2001/XMLSchema#int"
    >1</j.0:hasID>
    <j.0:hasDistance rdf:datatype="http://www.w3.org/2001/XMLSchema#double"
    >0.0</j.0:hasDistance>
  </j.0:Observation>
</rdf:RDF>