Step 0: From RDFS to Java code
To use RDFReactor, you need an ontology, like
For each object in the ontology, RDFReactor will generate a class with links between objects realised as Java properties.
 generating from RDFS
String rdfsFile = "./src/main/java/org/ontoware/semweb4j/lessons/lesson5/peopletag.rdfs.n3"; String outDir = "./src/main/java/"; String targetPackage = "org.ontoware.semweb4j.lessons.lesson5.gen"; String semantics = CodeGenerator.SEMANTICS_RDFS;
You will be able to use in future versions:
But semantics other than RDFS is currently not supported.
boolean skipBuiltins = true; boolean alwaysWriteToModel = true; String prefix = ""; CodeGenerator.generate(rdfsFile, outDir, targetPackage, semantics, skipBuiltins, alwaysWriteToModel, prefix);
outDir is where the files are put, targetPackage is written in the header of each file. If skipBuiltins is set to false, internal helper classes are re-built even if it's not necessary. Normally, you don't need this. The prefix String can be set to e.g. "gen_" to let all generated classes have that prefix.
The classes generated by running this code are ready-to-use. Remember: don't generate always before using the classes - if you didn't change the ontology, there is no need to rebuild the code!
 ontology used in example
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> . @prefix owl: <http://www.w3.org/2002/07/owl#> . @prefix xsd: <http://www.w3.org/2001/XMLSchema#> . @prefix foaf: <http://xmlns.com/foaf/0.1/#> . @prefix : <http://example.com/semweb4j#> . # classes :Person a rdfs:Class ; rdfs:label "Person" ; rdfs:comment "the 'atoms' of PeopleTag, people" ; owl:sameAs foaf:Person . :Tag a rdfs:Class ; rdfs:label "Tag" ; rdfs:comment "the tags which are assigned to people" . # properties of objects :name a rdf:Property ; rdfs:label "has name" ; rdfs:comment "a name of a person or tag" ; rdfs:subPropertyOf rdfs:label ; rdfs:domain :Person ; rdfs:domain :Tag ; rdfs:range rdfs:Literal . :tag a rdf:Property ; rdfs:label "has tag" ; rdfs:comment "a tag which has been assigned" ; rdfs:subPropertyOf rdfs:label ; rdfs:domain :Person ; rdfs:range :Tag . # relations between objects :knows a rdf:Property ; rdfs:label "knows" ; rdfs:comment "a known person" ; rdfs:domain :Person ; rdfs:range :Person ; owl:sameAs foaf:knows .
This is N3 notation. The OWL snippets aren't problematic for RDFReactor - with SEMANTICS.RDFS, they are just ignored.
JModel JPackage org.ontoware.semweb4j.lessons.lesson5.gen JClass Tag -> http://example.com/semweb4j#Tag extends: Thing, comment: the tags which are assigned to people Name (-1/-1) -> http://example.com/semweb4j#name, types: 'java.lang.String',. Inverse: Name. JClass Person -> http://example.com/semweb4j#Person extends: Thing, comment: the 'atoms' of PeopleTag, people Name (-1/-1) -> http://example.com/semweb4j#name, types: 'java.lang.String',. Inverse: Name. Tag (-1/-1) -> http://example.com/semweb4j#tag, types: 'Tag',. Inverse: Tag. Knows (-1/-1) -> http://example.com/semweb4j#knows, types: 'Person',. Inverse: Knows. JClass Thing -> http://www.w3.org/2000/01/rdf-schema#Class extends: org.ontoware.rdfreactor.schema.rdfschema.Class, comment: This class acts as a catch-all for all properties, for which no domain has specified. >>>>>> written to /home/konrad/workspace/semweb4j/tutorial/./src/main/java
The generated code is discussed in the next step.