code: package it.unibz.inf.ontop.model.vocabulary;
  
  import org.apache.commons.rdf.api.IRI;
  import org.apache.commons.rdf.simple.SimpleRDF;
  
  public class OFN {
  
      // Adapted from https://graphdb.ontotext.com/free/devhub/time-functions.html
      public static final String PREFIX = "http://www.ontotext.com/sparql/functions/";
  
      /*
       * Time extension - duration arithmetic
       */
      public static final IRI WEEKS_BETWEEN;
  
      public static final IRI DAYS_BETWEEN;
  
      public static final IRI HOURS_BETWEEN;
  
      public static final IRI MINUTES_BETWEEN;
  
      public static final IRI SECONDS_BETWEEN;
  
      public static final IRI MILLIS_BETWEEN;
  
      static {
          org.apache.commons.rdf.api.RDF factory = new SimpleRDF();
  
          /*
           * Time extension - duration arithmetic
           */
          WEEKS_BETWEEN = factory.createIRI(PREFIX + "weeksBetween");
  
          DAYS_BETWEEN = factory.createIRI(PREFIX + "daysBetween");
  
          HOURS_BETWEEN = factory.createIRI(PREFIX + "hoursBetween");
  
          MINUTES_BETWEEN = factory.createIRI(PREFIX + "minutesBetween");
  
          SECONDS_BETWEEN = factory.createIRI(PREFIX + "secondsBetween");
  
          MILLIS_BETWEEN = factory.createIRI(PREFIX + "millisBetween");
      }
  }
  
  