How protege shows OWL axioms in readable format - owl

Question

I have owl file containing some axioms :
<rdfs:subClassOf>
<owl:Restriction>
<owl:onProperty rdf:resource="namespace#Gender"/>
<owl:hasValue>M</owl:hasValue>
</owl:Restriction>
</rdfs:subClassOf>
<rdfs:subClassOf>
<owl:Restriction>
<owl:onProperty rdf:resource="namespace#Address"/>
<owl:minQualifiedCardinality rdf:datatype="&xsd;nonNegativeInteger">1</owl:minQualifiedCardinality>
<owl:onDataRange rdf:resource="&xsd;string"/>
</owl:Restriction>
</rdfs:subClassOf>
For above two axioms protege shows readable string as :
Gender value "M"
Address min 1 xsd:string
The question is how protege generates these readable strings from OWL file ?
Also if I want to create new axiom from these strings how to do that ? (converting axiom to readable string and then convert readable string to axiom back)

Answer 1

The readable format you show is Manchester OWL syntax.
In order to output an ontology in this format, you can use owl api code:
OWLOntology ontology = ...// load or create the ontology
OutputStream out = ... // any output stream will do
ontology.getOWLOntologyManager().saveOntology(ontology, new ManchesterSyntaxDocumentFormat(), out);
out.close();
Parsing a full ontology in Manchester syntax format happens like any other ontology: ontologyManager.loadOntologyFromOntologyDocument() with an input file.
Parsing single axioms is possible but much harder, because the format relies on prefixes set once for a whole ontology; so a lot of setup code is required. I would not recommend doing that as a starter project.