jena

问题 Is there a way to get the base namespace from a OWL ontology file, without using DOM or similar, but just using Jena's API? E.g., from an OWL file: <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:protege="http://protege.stanford.edu/plugins/owl/protege#" xmlns="http://www.owl-ontologies.com/Ontology1254827934.owl#" xmlns:xsp="http://www.owl-ontologies.com/2005/08/07/xsp.owl#" xmlns:owl="http://www.w3.org/2002/07/owl#" xmlns:xsd="http://www.w3.org/2001/XMLSchema#" xmlns

问题 I have a serious problem to get any reasoner up and running. Also the examples from the documentation: https://jena.apache.org/documentation/inference/ does not work here. I transferred the example into a unit test, so that the problem might be easier reproduced. Is reasoning limited to certain environment like a spatial JDK or so on, or am i getting something wrong? Thanks Here the example code (as java unit test): import static org.junit.Assert.assertNotNull; import java.io.PrintWriter;

问题 I have a local version of LinkedMDB that is in N-Triples format and want to query it. Now, I want to use Jena TDB, which can store the data that can be used for querying later. I checked the documentation for TDB Java API, but was unable to load the N-Triples file and then query with SPARQL. I've used the following code: String directory = "E:\\Applications\\tdb-0.8.9\\TDB-0.8.9\\bin\\tdb"; Dataset dataset = TDBFactory.createDataset(directory); // assume we want the default model, or we could

问题 Recently, I'm trying to approach semantic web using Jena to create RDF and make query. Now, I have successfully made a owl based RDF file in Jena. However, when I trying to use different ontologies (such as: cidoc-crm), I do not know how to import those ontologies to Jena. Does anyone know how to import them to Jena? Do I need to create a new ontology model? 回答1: Jena's OntModel interface provides a convenient way of working with ontologies (including RDFS ontologies). The following code

问题 I have got two RDF documents: http://dublincore.org/2012/06/14/dcterms.rdf http://xmlns.com/foaf/spec/index.rdf I would like to merge them into one file, e.g., purl_foaf.rdf . I am working in Java; how can I do this with Jena? 回答1: Jena has a built-in command line utility to do this: rdfcat. So, to join those two RDF files together and write the results as Turtle in the file purl_foaf.rdf , do the following from your command line. It should be on one line, but I've split it up for readability

问题 Suppose I have the following RDF data: @prefix : <urn:ex:> :m :A "a" :m :A "b" :m :A "c" :m :B "a" :m :B "b" What SPARQL query could I use to check whether the RDF model satisfies the following logical formula? ∀x A(X) → B(x) 回答1: SPARQL doesn't have conditionals or universal quantification, but does have existentials (does anything match this?), (implicit) conjunction and negation (in the 'absence' sense). So rewrite the question: ∀x A(x) → B(x) ⇒ ∀x ¬ ( A(x) ∧ ¬ B(x) ) ⇒ ¬ ∃x A(x) ∧ ¬ B(x)

问题 I am using Jena to query an owl file through Eclipse. I want to do some successive queries and every new query will use the results of the previous query. I want to do it in different ?SELECT and save every time the result of a query in order to use it again in a new query. I dont want to insert the values of the variables by myself but automatically occur from the queries. Any ideas whats a suitable way to achieve this? Thanks in advance 回答1: I think that there are two primary options here:

问题 I'm using the Jena framework to manipulate RDF files, but I can't find a way to validate a RDF with your respective RDFSchema. I'm trying this method bellow: Model mod1 = new ModelMem(); Model modSchema = new ModelMem(); String baseURI = "http://iec.ch/TC57/2007/network"; String rdfPath = "file:D:\\modelo.rdf"; InputStream model = FileManager.get().open(rdfPath); String rdfPathSchema = "file:D:\\Schema.rdf"; InputStream modelSchema = FileManager.get().open(rdfPathSchema); mod1.read(model,

问题 I am trying to extract RDF triples from XML files by using an existing ontology. I am using Java, and can use XPath to extract data from XML and Jena to read and write RDF documents and ontologies. How can I extract the relevant triples from the XML according to the existing ontology? 回答1: Forget about XPath to extract triples, it way easier and less problematic with Jena. You can use the interface SimpleSelector together with model.listStatements from Jena. In this example I am using

问题 I want to programmatically generate an ontology using OWL by supplying a vector. My goal is to be able to open the produced OWL file in Protégé and make use of Jena. Input Vector The vector which i want to pass: [[layer, network layer, data link layer, physical layer], [network, computer network], [data link], [ontology, ontology extraction]]. Expected Output The output should have the following tree-like hierarchy structure: layer -network layer -data link layer -physical layer network