AGFederationSparqlReasoning.java

package com.franz.agbase.examples;

import com.franz.agbase.*;

public class AGFederationSparqlReasoning {

    /**
     * Demonstrates SPARQL over a federation with and without reasoning.
     * 
     * @param args unused
     * @throws AllegroGraphException
     */
    public static void main(String[] args) throws AllegroGraphException {
        
        // Connect to the default server, which must already be running.
        AllegroGraphConnection ags = new AllegroGraphConnection();
        try {
            ags.enable();
        } catch (Exception e) {
            throw new AllegroGraphException("Server connection problem.", e);
        }

        // Register namespaces
        // Future AllegroGraph instances on this connection will get this.
        ags.registerNamespace("ex", "http://example.org/");
        
        // Create triple stores for this example
        AllegroGraph ts1 = ags.renew("ontology", AGPaths.TRIPLE_STORES);
        AllegroGraph ts2 = ags.renew("facts", AGPaths.TRIPLE_STORES);
        
        // Create a federated store consisting of the first 2 open stores above 
        AllegroGraph[] parts = {ts1,ts2};
        AllegroGraph fed = ags.federate("federation", parts, true);

        // Add some ontology
        ts1.addStatement("!ex:SmallBlackDog","!rdfs:subClassOf","!ex:BlackDog");  
        ts1.addStatement("!ex:BlackDog","!rdfs:subClassOf","!ex:Dog");  
        ts1.addStatement("!ex:Dog","!rdfs:subClassOf","!ex:Mammal");  
        ts1.addStatement("!ex:Giraffe","!rdfs:subClassOf","!ex:Mammal");  
        ts1.addStatement("!ex:Lion","!rdfs:subClassOf","!ex:Mammal");  
        ts1.addStatement("!ex:Mammal","!rdfs:subClassOf","!ex:Animal");  
         
        // Add some facts 
        ts2.addStatement("!ex:Abbey","!rdf:type","!ex:BlackDog");
        
        String query = 
            "PREFIX ex: <http://example.org/>"
            + "PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> "
            + "SELECT ?class "
            + "WHERE { "
            + "  ex:Abbey rdf:type ?class . "
            + "}";
        
        // Sparql query over the federation without reasoning
        SPARQLQuery sq = new SPARQLQuery();
        sq.setTripleStore(fed);
        sq.setQuery(query);
        sq.setIncludeInferred(false);
        AGSparqlSelect.doSparqlSelect(sq);
        
        // Sparql query over the federation with RDFS++ reasoning
        sq.setIncludeInferred(true);
        AGSparqlSelect.doSparqlSelect(sq);
        
        // Close all stores and disconnect from the server
        fed.closeTripleStore();
        ts1.closeTripleStore();
        ts2.closeTripleStore();
        ags.disable();
    }
    
}

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