Is it possible to get name of all the classes present in OWL file using JENA and store in the Array List?
OntModel base = ModelFactory.createOntologyModel(OntModelSpec.OWL_MEM, null);
OntModel model = ModelFactory.createOntologyModel(OntModelSpec.OWL_MEM_MICRO_RULE_INF, null);
String NS = "http://www.abc.com/abcportal/abc.owl" + "#";
base.read("file:abcInstance.owl");
ExtendedIterator<OntClass> iter = base.listClasses();
while ( iter.hasNext()){
System.out.println(iter.next());
}
Yes it is, see the Javadoc for OntModel.listClasses. You can easily copy the contents of the Iterator into an array or List. That you're asking the question suggests that you'll probably benefit from reading the Jena ontology API documentation
Related
I am new in the semantic web field, and i'm trying to create a java model using JENA to extract classes, subclass and/or comments from an OWL file..
any help/guidance on how to do such thing would be appreciated.
Thank you
You can do so with the Jena Ontology API. This API allows you to create an ontology model from owl file and then provides you access to all the information stored in the ontology as Java Classes.
Here is a quick introduction to Jena ontology. This introduction contains useful information on getting started with Jena Ontology.
The code generally looks like this:
String owlFile = "path_to_owl_file"; // the file can be on RDF or TTL format
/* We create the OntModel and specify what kind of reasoner we want to use
Depending on the reasoner you can acces different kind of information, so please read the introduction. */
OntModel model = ModelFactory.createOntologyModel(OntModelSpec.OWL_MEM);
/* Now we read the ontology file
The second parameter is the ontology base uri.
The third parameter can be TTL or N3 it represents the file format*/
model.read(owlFile, null, "RDF/XML");
/* Then you can acces the information using the OntModel methods
Let's access the ontology properties */
System.out.println("Listing the properties");
model.listOntProperties().forEachRemaining(System.out::println);
// let's access the classes local names and their subclasses
try {
base.listClasses().toSet().forEach(c -> {
System.out.println(c.getLocalName());
System.out.println("Listing subclasses of " + c.getLocalName());
c.listSubClasses().forEachRemaining(System.out::println);
});
} catch (Exception e) {
e.printStackTrace();
}
// Note that depending on the classes types, accessing some information might throw an exception.
Here is the Jena Ontology API JavaDoc.
I hope it was useful!
I have an input file in xml format and I need to convert it into a .rdf file that is based on an ontology model created.
Can anyone let me know what the suitable method is to do this using jena api in java?
Is your input file in some arbitrary XML format, or is it already serialized as RDF/XML? (ie: is the root tag of your document <rdf:RDF>?)
If it is in some arbitrary format, then you will need to define some rdf-based schema for representing your data. This is purely project-specific, and will require work on your part to define a way for a graph to apply to your data.
Once you have done that, then basic document construction is a topic for the Jena Tutorials. There is far too much material to cover here, but the basics of creating a statement should suffice:
final Model m = ModelFactory.createDefaultModel();
final Resource s = m.createResource("urn:ex:subject");
final Property p = m.createProperty("urn:ex:predicate");
final Resource o = m.createResource("urn:ex:object");
m.add(s,p,o);
try( final OutputStream out = Files.newOutputStream(Paths.createTempFile("tmp","rdf"), StandardOpenOptions.CREATE_NEW) ){
m.write(out, null, "RDF/XML");
}
The exercise of iterating over your XML and constructing the proper set of statements is left as an exercise for the reader.
If your data is already in RDF/XML, then you can directly read it in to a model:
// Assume you have an InputStream called 'in' pointing at your input data
final Model m = ModelFactory.createDefaultModel();
m.read(in, null, "RDF/XML"); // Assumed that there is no base
I am writing a DL query parser in Java. I need to use the method getObjectPropertyValues(). how to convert a string to OWL Object Property expression in Java , please give me a sample code.
If you are using the OWLAPI you can reuse the code from here for parsing a DL query:
https://github.com/owlcs/owlapi/wiki/DL-Queries-with-a-real-reasoner
You create an OWLObjectProperty using the aptly named OWLDataFactory.getOWLObjectProperty(IRI iri), and IRI has a constructor IRI(String). E.g., from the examples in the documentation:
OWLObjectProperty prop
= factory.getOWLObjectProperty(IRI.create(ontologyIRI + "#propA"));
I'm working on a way of programatically accessing a Lotus Notes database to gather information on embedded attachments of records over a given period.
My goal is to find records over a given period, then use Apache-POI to get metadata about document size, character count, etc.
The POI part works fine, and so far, I've been able to access the Lotus Notes records thanks to this help:
lotus notes search by date with Java api
and this answer also shows me how to download/copy the attachments:
How do I get all the attachments from a .nsf(lotus notes) file using java
from there I could use my POI code do my job and at the end, just delete the copied attachments. This approach, basically works, but I want to avoid the overhead of copying, saving and then at the end deleting my copy of these attached documents from the database.
I tried passing the result of the EmbeddedObject getSource() method as an input to my POI code and got a FileNotFoundException in the POI code that was expecting a String to make a File.
Is there a way of getting a File reference I can pass to POI, without copying and saving the attachment? Or, what I mean is, is it as simple as getting a File (+path) for the Lotus Notes EmbeddedObject attachment, and how do I do this?
I found the answer and posted it below.
Answering my own question...
...here's the solution I found a little while after posting the question above:
EmbeddedObject's getInputStream to the rescue...
//from the answer in the link in the question above　
Database db = agentContext.getCurrentDatabase();
DocumentCollection dc = db.getAllDocuments();
Document doc = dc.getFirstDocument();
boolean saveFlag = false;
while (doc != null) {
RichTextItem body =
(RichTextItem)doc.getFirstItem("Body");
System.out.println(doc.getItemValueString("Subject"));
Vector v = body.getEmbeddedObjects();
Enumeration e = embeddedObjs.elements();
while(e.hasMoreElements()){
EmbeddedObject eo = (EmbeddedObject)e.nextElement();
if(eo.getType() == EmbeddedObject.EMBED_ATTACHMENT){
//this next line gives Apache-POI access to the InputStream
InputStream is = eo.getInputStream();
POIFSFileSystem POIfs =
HWPFDocument.verifyAndBuildPOIFS(is);
POIOLE2TextExtractor extractor =
ExtractorFactory.createExtractor(POIfs);
System.out.println("extracted text: " + extractor.getText());
is.close(); //closing InputStream
}
eo.recycle(); //recycling EmbeddedObject
//thanks to rhsatrhs for the close() and recycle() tip!
I need a source code with java and jena (or other languages) that ables to extract triples from a RDF file that has multiple ontology.
There is a source code in This Page but this code needs to determine an ontology in source code.
I need a source code that itself read ontology from rdf files and print Sujects,Predicate and Objects as string in URL format.
This is my rdf file: My Files
Can anybody help me to solve this problem?
You just need to have the same code as in here:
How to extract RDF triples from xml file using existing Ontology in java?
But without the predicate that filters the statements. For example ...
FileManager fManager = FileManager.get();
Model model = fManager.loadModel("some_file.rdf");
SimpleSelector selector = new SimpleSelector(null, null, (RDFNode)null) {
public boolean selects(Statement s)
{ return true; }
}
StmtIterator iter = model.listStatements(selector);
while(it.hasNext()) {
Statement stmt = iter.nextStatement();
System.out.print(stmt.getSubject().toString());
System.out.print(stmt.getPredicate().toString());
System.out.println(stmt.getObject().toString());
}
If this is not what you need, please explain your question in further detail. I do not fully understand it.