RDFReactor

From semanticweb.org

Jump to: navigation, search
RDFReactor
Logo of RDFReactor
rdfreactor.semweb4j.org = this page
Status: stable
Last release: 4.6.2 (2008-00-09)
License: BSD licenses
Affiliation: FZI
Web resources

RDFReactor views the RDF data model through object-oriented Java proxies. It makes using RDF easy for Java developers. Technically, it translates an ontology into corresponding Java classes.

  • 1. Think in objects, not statements - Read and write RDF data using familiar Java objects, e.g. use 
person.setName("Max Mustermann")

instead of 

addTriple( personURI, nameURI, "Max Mustermann" )
  • 2. Dynamic state - all state information is at all times only in the RDF model in the triple store of your choice
  • 3. Java interfaces are generated automatically from an RDF Schema. Code generation via Velocity templates.

Contents

[edit] About

License: Since 13.02.07: RDFReactor is released under the new BSD license. Alternative licensing is possible, just ask us.

Download releases from the release directory

Short changelog: (please see changelog of modules for detailed changes)

  • 4.6.2
    • Fixed two minor bugs (getAllInstance_as is now getAllInstances, removeAllPROP() is now available more often)
  • 4.6.1
    • Reduced memory consumption of generator (was 1.5 GB, now is 250M for certain ontologies)

Dependends on Java 5.0, RDF2Go, Jena or Sesame, Velocity

[edit] Modules

[edit] rdfreactor.runtime

This module is needed at runtime to make the generated classes work.

  • Maven reports including links to JavaDocs, changelog, source code as HTML, JUnit test results, developer team, dependencies, list of open TODO tags in the code, ...
  • Releases (consider downloding the distribution instead)
  • Anonymous Subversion (use https:// for developer access)

[edit] rdfreactor.generator

This modules is only needed to generate classes. At runtime, it is not needed.

  • Maven reports including links to JavaDocs, changelog, source code as HTML, JUnit test results, developer team, dependencies, list of open TODO tags in the code, ...
  • Releases (consider downloding the distribution instead)
  • Anonymous Subversion (use https:// for developer access)

Note that the memory consumption for this module can be quite high, e.g. up to 250M for some larger ontologies.

[edit] Documentation

  • List of open issues - check here if you have a problem or add a new one.

[edit] Introduction to use RDFReactor

The easiest way is to generate Java classes from an RDFS ontology by simply calling a very short Java program from within eclipse. Here you see such a mini-application. It will load an RDF schema from ./data/schema.n3, and generate .java files in src/gen. The generated classes will all have the package declaration org.ontoware.myproject and the ontology will be interpreted as RDFS semantics. Automatically, however, OWL cardinality constraints will be used, if present. The true,true at the end of the method call means that build-ins are skipped. If you set this to false, you re-generate classes for e.g. rdf:Resource, which is redundant. The second true triggers whether rdf:type statements are automatically written to the model. If you create a new Person p with p = new Person( model, someURI ) then automatically the statement (someURI, rdf:type, :Person) will be added to the model. 

package org.ontoware.rdfreactor.example;

import org.ontoware.rdf2go.Reasoning;
import org.ontoware.rdfreactor.generator.CodeGenerator;

public class GenerateSomething throws Exception {
 
	public static void main(String[] args) {
		// "./data/myschema.n3" - 
           // "src/gen" -
           // 
		CodeGenerator.generate("./data/myschema.n3", "src/gen",
				"org.ontoware.myproject", Reasoning.rdfs, true, true);
	}
}

[edit] Developer Workflow

Create API

  • Write or find an RDF Schema
  • Generate API 
CodeGenerator.generate("./data/schema.n3", "./src", "org.ontoware.rdfreactor.example","rdfs", true, true);

Use API - Set up RDFReactor 

// create an RDF2Go wrapper, e.g. around a Jena data model, which holds all data at runtime

Model m = ...

Use RDFReactor 

Person p1 = new Person(m, "http://www.example.com/ns/2005/#person1");
Person p2 = new Person(m, "http://www.example.com/ns/2005/#person2");
Person p3 = new Person(m, "http://www.example.com/ns/2005/#person3");
p1.setName("Joe");
p1.addKnows(p2);
p1.addKnows(p3);
p2.setName("Jim");
p3.setName("Jon");
               
Person[] p1friends = p1.getAllKnows();
for (int i = 0; i < p1friends.length; i  ) {
 System.out.println(p1.getName() " knows " p1friends[i].getName() );
}

[edit] Contact

Currently there is no mailinglist.

Acknowledgements

Retrieved from "http://semanticweb.org/wiki/RDFReactor"
Personal tools