AGRangeQueries.java

package com.franz.agbase.examples;

import com.franz.agbase.*;

public class AGRangeQueries {

    /**
     * Demonstrates some basics of range queries. 
     *
     * @param args 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
        AllegroGraph ts = ags.renew("rangequeries", AGPaths.TRIPLE_STORES);

        // Register your namespaces
        ts.registerNamespace("ex","http://example.org/");
        
        // Add some triples to the store using encoded literals
        // Encoded literals are necessary when performing range queries 
        ts.addStatement("!ex:person1","!ex:age", ts.createEncodedLiteral(28,"int"));
        ts.addStatement("!ex:person2","!ex:age", ts.createEncodedLiteral(30,"int"));
        ts.addStatement("!ex:person3","!ex:age", ts.createEncodedLiteral(32,"int"));
        ts.addStatement("!ex:person4","!ex:age", ts.createEncodedLiteral(40,"int"));
        ts.addStatement("!ex:person5","!ex:age", ts.createEncodedLiteral(42,"int"));
        
        // Retrieve triples by matching a range of objects
        EncodedLiteral low = ts.createEncodedLiteral(30,"int");
        EncodedLiteral high = ts.createEncodedLiteral(40,"int");
        System.out.println("Retrieving triples with range 30 <= ex:age <= 40");
        TriplesIterator it = ts.getStatements(null, "!ex:age", low, high, null, null);
        AGUtils.showTriples(it);

        // Close the triple store and disconnect from the server
        ts.closeTripleStore();
        ags.disable();
    }

}

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