Inserting self defined object properties

For a school project, we have to use RDF and OWL to create a vacancy/applicant service. We are writing this service with Spring and Apache Jena. This service will contain persons that have certain skills and vacancies of companies that require some skills. We've created the ontologies, but we can't find out how to create a skill and link it to a person.

First we tried to make an hasSkill objectproperty directly to a foaf:person with the following code:

<owl:ObjectProperty rdf:about="foaf#hasSkill">

    <owl:domain owl:class="foaf#person" />

<owl:range owl:class="#Skill" />

</owl:ObjectProperty>

We tried inserting these skills using SparQL, but we couldn't find out how to link the created skill to an existing user. Another method we tried is accessing the property by code.

Resource user = userRepository.getUserResource(userID);

Property skill = model.createProperty("Skill");

Where the first line gets the user's resource by querrying it with SparQL.

The code defining the Skill-ontology:

<owl:Class owl:name="Skill">

<owl:Annotation>

    <owl:Label>Skill</owl:Label>

</owl:Annotation>

</owl:Class>



<owl:ObjectProperty rdf:about="http://localhost:8080/ontologies/Skill#SkillName">

  <owl:domain owl:class="Skill" />

  <owl:range owl:class="rdfs#literal"/>

</owl:ObjectProperty>



<owl:ObjectProperty rdf:about="http://localhost:8080/ontologies/Skill#CompetencyLevel">

  <owl:domain owl:class="Skill" />

  <owl:range owl:class="rdfs#literal" />

</owl:ObjectProperty>

The code defining our applicant ontology:

<owl:Class owl:name="Applicant">

    <owl:Annotation>

      <owl:Label>Applicant</owl:Label>

</owl:Annotation>

</owl:Class>



<owl:ObjectProperty rdf:about="http://localhost:8080/ontologies/Applicant#Person">

    <owl:domain owl:class="Applicant" />

  <owl:range owl:class="foaf#person" />

</owl:ObjectProperty>



<owl:ObjectProperty rdf:about="http://localhost:8080/ontologies/Degree#StudyField">

    <owl:domain owl:class="Applicant" />

    <owl:range owl:class="#Skill" />

</owl:ObjectProperty>

What we want to do is that an existing user can add skills to their profile. These skills then can be used to match vacancies to the applicant.

After the suggestion of AKSW, I tried to use the Resource class of Jena:

Property name = ResourceFactory.createProperty("", ns + "Skill#SkillName");

Property competencyLvl = ResourceFactory.createProperty("", ns + "Skill#CompetencyLevel");

Resource r = model.getModel().createResource("Skill")

            .addProperty(name, skillDetail.getSkillName())

            .addProperty(competencyLvl, skillDetail.getCompetencyLevel());



model.writeChanges();

The namespace (ns) is equal to "http://localhost:8080/ontologies/"
But this gives me the error that a required component is missing in the scheme.

edited Jan 2 at 16:38

asked Jan 2 at 14:17

Bram Kelchtermans

The class Resource provides all the methods you need, e.g. addProperty, addLiteral etc. - Javadoc or the Apache Jena doc is always your friend

– AKSW
Jan 2 at 14:28

@AKSW thanks for the response! I tried your suggestion, but the addProperty requires a property instance, which I created with the resourceFactory with namespace "" and for example localName ns + "Skill#SkillName. But i get an error that a required component is missing in the scheme

– Bram Kelchtermans
Jan 2 at 15:49

Can you please add the code that doesn't work to the question? It's easier for me to reproduce resp. find the mistake. Note, it has to be a proper URL, please also show the String you're passing to the resource factory.

– AKSW
Jan 2 at 16:01

@AKSW Done, thanks for your time!

– Bram Kelchtermans
Jan 2 at 16:04

Ok, so why ResourceFactory.createProperty("", ns + "Skill#SkillName"); ? The frist argument is supposed to be the namespace, you just pass "" . Look at the Javadoc again: createProperty(String namespace, String localName) - so, shouldn't it createProperty(ns, "Skill#SkillName") ?

– AKSW
Jan 2 at 16:37

|
show 5 more comments

First we tried to make an hasSkill objectproperty directly to a foaf:person with the following code:

<owl:ObjectProperty rdf:about="foaf#hasSkill">

    <owl:domain owl:class="foaf#person" />

<owl:range owl:class="#Skill" />

</owl:ObjectProperty>

We tried inserting these skills using SparQL, but we couldn't find out how to link the created skill to an existing user. Another method we tried is accessing the property by code.

Resource user = userRepository.getUserResource(userID);

Property skill = model.createProperty("Skill");

Where the first line gets the user's resource by querrying it with SparQL.

The code defining the Skill-ontology:

<owl:Class owl:name="Skill">

<owl:Annotation>

    <owl:Label>Skill</owl:Label>

</owl:Annotation>

</owl:Class>



<owl:ObjectProperty rdf:about="http://localhost:8080/ontologies/Skill#SkillName">

  <owl:domain owl:class="Skill" />

  <owl:range owl:class="rdfs#literal"/>

</owl:ObjectProperty>



<owl:ObjectProperty rdf:about="http://localhost:8080/ontologies/Skill#CompetencyLevel">

  <owl:domain owl:class="Skill" />

  <owl:range owl:class="rdfs#literal" />

</owl:ObjectProperty>

The code defining our applicant ontology:

<owl:Class owl:name="Applicant">

    <owl:Annotation>

      <owl:Label>Applicant</owl:Label>

</owl:Annotation>

</owl:Class>



<owl:ObjectProperty rdf:about="http://localhost:8080/ontologies/Applicant#Person">

    <owl:domain owl:class="Applicant" />

  <owl:range owl:class="foaf#person" />

</owl:ObjectProperty>



<owl:ObjectProperty rdf:about="http://localhost:8080/ontologies/Degree#StudyField">

    <owl:domain owl:class="Applicant" />

    <owl:range owl:class="#Skill" />

</owl:ObjectProperty>

What we want to do is that an existing user can add skills to their profile. These skills then can be used to match vacancies to the applicant.

After the suggestion of AKSW, I tried to use the Resource class of Jena:

Property name = ResourceFactory.createProperty("", ns + "Skill#SkillName");

Property competencyLvl = ResourceFactory.createProperty("", ns + "Skill#CompetencyLevel");

Resource r = model.getModel().createResource("Skill")

            .addProperty(name, skillDetail.getSkillName())

            .addProperty(competencyLvl, skillDetail.getCompetencyLevel());



model.writeChanges();

The namespace (ns) is equal to "http://localhost:8080/ontologies/"
But this gives me the error that a required component is missing in the scheme.

edited Jan 2 at 16:38

asked Jan 2 at 14:17

Bram Kelchtermans

The class Resource provides all the methods you need, e.g. addProperty, addLiteral etc. - Javadoc or the Apache Jena doc is always your friend

– AKSW
Jan 2 at 14:28

@AKSW thanks for the response! I tried your suggestion, but the addProperty requires a property instance, which I created with the resourceFactory with namespace "" and for example localName ns + "Skill#SkillName. But i get an error that a required component is missing in the scheme

– Bram Kelchtermans
Jan 2 at 15:49

Can you please add the code that doesn't work to the question? It's easier for me to reproduce resp. find the mistake. Note, it has to be a proper URL, please also show the String you're passing to the resource factory.

– AKSW
Jan 2 at 16:01

@AKSW Done, thanks for your time!

– Bram Kelchtermans
Jan 2 at 16:04

Ok, so why ResourceFactory.createProperty("", ns + "Skill#SkillName"); ? The frist argument is supposed to be the namespace, you just pass "" . Look at the Javadoc again: createProperty(String namespace, String localName) - so, shouldn't it createProperty(ns, "Skill#SkillName") ?

– AKSW
Jan 2 at 16:37

|
show 5 more comments

First we tried to make an hasSkill objectproperty directly to a foaf:person with the following code:

<owl:ObjectProperty rdf:about="foaf#hasSkill">

    <owl:domain owl:class="foaf#person" />

<owl:range owl:class="#Skill" />

</owl:ObjectProperty>

We tried inserting these skills using SparQL, but we couldn't find out how to link the created skill to an existing user. Another method we tried is accessing the property by code.

Resource user = userRepository.getUserResource(userID);

Property skill = model.createProperty("Skill");

Where the first line gets the user's resource by querrying it with SparQL.

The code defining the Skill-ontology:

<owl:Class owl:name="Skill">

<owl:Annotation>

    <owl:Label>Skill</owl:Label>

</owl:Annotation>

</owl:Class>



<owl:ObjectProperty rdf:about="http://localhost:8080/ontologies/Skill#SkillName">

  <owl:domain owl:class="Skill" />

  <owl:range owl:class="rdfs#literal"/>

</owl:ObjectProperty>



<owl:ObjectProperty rdf:about="http://localhost:8080/ontologies/Skill#CompetencyLevel">

  <owl:domain owl:class="Skill" />

  <owl:range owl:class="rdfs#literal" />

</owl:ObjectProperty>

The code defining our applicant ontology:

<owl:Class owl:name="Applicant">

    <owl:Annotation>

      <owl:Label>Applicant</owl:Label>

</owl:Annotation>

</owl:Class>



<owl:ObjectProperty rdf:about="http://localhost:8080/ontologies/Applicant#Person">

    <owl:domain owl:class="Applicant" />

  <owl:range owl:class="foaf#person" />

</owl:ObjectProperty>



<owl:ObjectProperty rdf:about="http://localhost:8080/ontologies/Degree#StudyField">

    <owl:domain owl:class="Applicant" />

    <owl:range owl:class="#Skill" />

</owl:ObjectProperty>

What we want to do is that an existing user can add skills to their profile. These skills then can be used to match vacancies to the applicant.

After the suggestion of AKSW, I tried to use the Resource class of Jena:

Property name = ResourceFactory.createProperty("", ns + "Skill#SkillName");

Property competencyLvl = ResourceFactory.createProperty("", ns + "Skill#CompetencyLevel");

Resource r = model.getModel().createResource("Skill")

            .addProperty(name, skillDetail.getSkillName())

            .addProperty(competencyLvl, skillDetail.getCompetencyLevel());



model.writeChanges();

The namespace (ns) is equal to "http://localhost:8080/ontologies/"
But this gives me the error that a required component is missing in the scheme.

edited Jan 2 at 16:38

asked Jan 2 at 14:17

Bram Kelchtermans

First we tried to make an hasSkill objectproperty directly to a foaf:person with the following code:

<owl:ObjectProperty rdf:about="foaf#hasSkill">

    <owl:domain owl:class="foaf#person" />

<owl:range owl:class="#Skill" />

</owl:ObjectProperty>

We tried inserting these skills using SparQL, but we couldn't find out how to link the created skill to an existing user. Another method we tried is accessing the property by code.

Resource user = userRepository.getUserResource(userID);

Property skill = model.createProperty("Skill");

Where the first line gets the user's resource by querrying it with SparQL.

The code defining the Skill-ontology:

<owl:Class owl:name="Skill">

<owl:Annotation>

    <owl:Label>Skill</owl:Label>

</owl:Annotation>

</owl:Class>



<owl:ObjectProperty rdf:about="http://localhost:8080/ontologies/Skill#SkillName">

  <owl:domain owl:class="Skill" />

  <owl:range owl:class="rdfs#literal"/>

</owl:ObjectProperty>



<owl:ObjectProperty rdf:about="http://localhost:8080/ontologies/Skill#CompetencyLevel">

  <owl:domain owl:class="Skill" />

  <owl:range owl:class="rdfs#literal" />

</owl:ObjectProperty>

The code defining our applicant ontology:

<owl:Class owl:name="Applicant">

    <owl:Annotation>

      <owl:Label>Applicant</owl:Label>

</owl:Annotation>

</owl:Class>



<owl:ObjectProperty rdf:about="http://localhost:8080/ontologies/Applicant#Person">

    <owl:domain owl:class="Applicant" />

  <owl:range owl:class="foaf#person" />

</owl:ObjectProperty>



<owl:ObjectProperty rdf:about="http://localhost:8080/ontologies/Degree#StudyField">

    <owl:domain owl:class="Applicant" />

    <owl:range owl:class="#Skill" />

</owl:ObjectProperty>

What we want to do is that an existing user can add skills to their profile. These skills then can be used to match vacancies to the applicant.

After the suggestion of AKSW, I tried to use the Resource class of Jena:

Property name = ResourceFactory.createProperty("", ns + "Skill#SkillName");

Property competencyLvl = ResourceFactory.createProperty("", ns + "Skill#CompetencyLevel");

Resource r = model.getModel().createResource("Skill")

            .addProperty(name, skillDetail.getSkillName())

            .addProperty(competencyLvl, skillDetail.getCompetencyLevel());



model.writeChanges();

The namespace (ns) is equal to "http://localhost:8080/ontologies/"
But this gives me the error that a required component is missing in the scheme.

java rdf jena owl foaf

edited Jan 2 at 16:38

asked Jan 2 at 14:17

Bram Kelchtermans

edited Jan 2 at 16:38

asked Jan 2 at 14:17

Bram Kelchtermans

edited Jan 2 at 16:38

asked Jan 2 at 14:17

Bram Kelchtermans

asked Jan 2 at 14:17

Bram Kelchtermans

asked Jan 2 at 14:17

Bram Kelchtermans

The class Resource provides all the methods you need, e.g. addProperty, addLiteral etc. - Javadoc or the Apache Jena doc is always your friend

– AKSW
Jan 2 at 14:28

@AKSW thanks for the response! I tried your suggestion, but the addProperty requires a property instance, which I created with the resourceFactory with namespace "" and for example localName ns + "Skill#SkillName. But i get an error that a required component is missing in the scheme

– Bram Kelchtermans
Jan 2 at 15:49

Can you please add the code that doesn't work to the question? It's easier for me to reproduce resp. find the mistake. Note, it has to be a proper URL, please also show the String you're passing to the resource factory.

– AKSW
Jan 2 at 16:01

@AKSW Done, thanks for your time!

– Bram Kelchtermans
Jan 2 at 16:04

Ok, so why ResourceFactory.createProperty("", ns + "Skill#SkillName"); ? The frist argument is supposed to be the namespace, you just pass "" . Look at the Javadoc again: createProperty(String namespace, String localName) - so, shouldn't it createProperty(ns, "Skill#SkillName") ?

– AKSW
Jan 2 at 16:37

|
show 5 more comments

The class Resource provides all the methods you need, e.g. addProperty, addLiteral etc. - Javadoc or the Apache Jena doc is always your friend

– AKSW
Jan 2 at 14:28

@AKSW thanks for the response! I tried your suggestion, but the addProperty requires a property instance, which I created with the resourceFactory with namespace "" and for example localName ns + "Skill#SkillName. But i get an error that a required component is missing in the scheme

– Bram Kelchtermans
Jan 2 at 15:49

Can you please add the code that doesn't work to the question? It's easier for me to reproduce resp. find the mistake. Note, it has to be a proper URL, please also show the String you're passing to the resource factory.

– AKSW
Jan 2 at 16:01

@AKSW Done, thanks for your time!

– Bram Kelchtermans
Jan 2 at 16:04

Ok, so why ResourceFactory.createProperty("", ns + "Skill#SkillName"); ? The frist argument is supposed to be the namespace, you just pass "" . Look at the Javadoc again: createProperty(String namespace, String localName) - so, shouldn't it createProperty(ns, "Skill#SkillName") ?

– AKSW
Jan 2 at 16:37

The class Resource provides all the methods you need, e.g. addProperty, addLiteral etc. - Javadoc or the Apache Jena doc is always your friend

– AKSW
Jan 2 at 14:28

@AKSW thanks for the response! I tried your suggestion, but the addProperty requires a property instance, which I created with the resourceFactory with namespace "" and for example localName ns + "Skill#SkillName. But i get an error that a required component is missing in the scheme

– Bram Kelchtermans
Jan 2 at 15:49

Can you please add the code that doesn't work to the question? It's easier for me to reproduce resp. find the mistake. Note, it has to be a proper URL, please also show the String you're passing to the resource factory.

– AKSW
Jan 2 at 16:01

@AKSW Done, thanks for your time!

– Bram Kelchtermans
Jan 2 at 16:04

Ok, so why ResourceFactory.createProperty("", ns + "Skill#SkillName"); ? The frist argument is supposed to be the namespace, you just pass "" . Look at the Javadoc again: createProperty(String namespace, String localName) - so, shouldn't it createProperty(ns, "Skill#SkillName") ?

– AKSW
Jan 2 at 16:37

|
show 5 more comments

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