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AGPrologFunctorQminus.java

package com.franz.agbase.examples;



import com.franz.agbase.*;



public class AGPrologFunctorQminus {



    /**

     * Demonstrates some basics of using functor q- in PrologSelect queries. 

     * 

     * @param unused

     * @throws AllegroGraphException 

     */

    public static void main(String[] args) throws AllegroGraphException {

        // Connect to server, which must already be running.

        AllegroGraphConnection ags = new AllegroGraphConnection();

        try {

            ags.enable();

        } catch (Exception e) {

            throw new AllegroGraphException("Server connection problem", e);

        }

        // Create a fresh triple-store for this example.

        AllegroGraph ts = ags.renew("functorqminus", AGPaths.TRIPLE_STORES);

        

        // Register your namespaces

        ts.registerNamespace("ex","http://example.org/");

        

        // Add some triples to the store

        ts.addStatement("!ex:a","!ex:owned-by","!ex:b");

        ts.addStatement("!ex:c","!ex:owns","!ex:d");

        ts.addStatement("!ex:jans","!ex:owns","!ex:birra");

        ts.addStatement("!ex:owned-by","!owl:inverseOf","!ex:owns");



        // index the store

        ts.indexAllTriples();

        

        // Set up a Prolog query object that does RDFS++ reasoning

        // over the store

        PrologSelectQuery q = new PrologSelectQuery();

        q.setTripleStore(ts);

        q.setIncludeInferred(true);



        // First a query with the q functor.  This will include inferred

        // results because the includeInferred setting is true.

        String[] vars = new String[]{"x","y"};

        String pquery = "(q ?x !ex:owns ?y)";

        q.setVariables(vars);

        q.setQuery(pquery);

        ValueSetIterator it = q.run();

        System.out.println("Results for " + pquery);

        AGUtils.showResults(it);



        // Now a query with the q- functor.  This returns results that don't

        // involve reasoner, overriding any "includeInferred" setting on the

        // the query (but just for this clause).  It allows disabling of

        // reasoning on a clause-by-clause basis for queries involving

        // multiple clauses.

        pquery = "(q- ?x !ex:owns ?y)";

        q.setVariables(vars);

        q.setQuery(pquery);

        it = q.run();

        System.out.println("Results for " + pquery);

        AGUtils.showResults(it);



        // Add some more triples to the store

        ts.addStatement("!ex:A","!rdfs:subClassOf", "!ex:B");

        ts.addStatement("!ex:B","!rdfs:subClassOf", "!ex:C");

        ts.addStatement("!ex:a","!rdf:type", "!ex:A");

        

        // index again

        ts.indexAllTriples();

        

        // Another query without reasoning using functor q- 

        pquery = "(q- ?x !rdf:type ?y)";

        q.setVariables(vars);

        q.setQuery(pquery);

        it = q.run();

        System.out.println("Results for " + pquery);

        AGUtils.showResults(it);



        // Now demonstrate reasoning with functor q

        pquery = "(q ?x !rdf:type ?y)";

        q.setVariables(vars);

        q.setQuery(pquery);

        it = q.run();

        System.out.println("Results for " + pquery);

        AGUtils.showResults(it);

        

        // Close the triple store and disconnect from the server.

        ts.closeTripleStore();

        ags.disable();

    }



}
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