eu.mondo.driver.fourstore.FourStoreGraphDriverReadOnly.java Source code

Introduction

Here is the source code for eu.mondo.driver.fourstore.FourStoreGraphDriverReadOnly.java

Source

/*******************************************************************************
 * Copyright (c) 2010-2014, Gabor Szarnyas, Istvan Rath and Daniel Varro
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 * Gabor Szarnyas - initial API and implementation
 *******************************************************************************/
package eu.mondo.driver.fourstore;

import java.io.BufferedReader;
import java.io.IOException;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.Multimap;

import eu.mondo.driver.graph.RDFGraphDriverReadOnly;
import eu.mondo.driver.graph.util.RDFUtil;

public class FourStoreGraphDriverReadOnly extends FourStoreGraphDriverQueryExecutor
        implements RDFGraphDriverReadOnly {

    protected static final String RDF_PREFIX = "http://www.w3.org/1999/02/22-rdf-syntax-ns#";
    protected static final String SPARQL_RDF_PREFIX = "PREFIX rdf: <" + RDF_PREFIX + "> ";

    public FourStoreGraphDriverReadOnly(final String connectionString) {
        super(connectionString);
    }

    @Override
    public long countVertices(final String type) throws IOException {
        final String query = SPARQL_RDF_PREFIX
                + String.format("SELECT (COUNT(?x) AS ?count) WHERE {?x rdf:type %s}", RDFUtil.brackets(type));
        final BufferedReader reader = runQuery(query);

        // skip the first line
        reader.readLine();

        final String line = reader.readLine();
        return Integer.parseInt(line);
    }

    @Override
    public long countEdges(final String type) throws IOException {
        final String query = String.format("SELECT (COUNT(?x) AS ?count) WHERE {?x %s ?y}", RDFUtil.brackets(type));
        final BufferedReader reader = runQuery(query);

        // skip the first line
        reader.readLine();

        final String line = reader.readLine();
        return Integer.parseInt(line);
    }

    @Override
    public long countProperties(final String type) throws IOException {
        return countEdges(type);
    }

    @Override
    public List<Long> collectVertices(final String type) throws IOException {
        final String queryString = String.format(SPARQL_RDF_PREFIX + "SELECT ?a WHERE { ?a rdf:type %s }",
                RDFUtil.brackets(type));
        return queryIds(queryString);
    }

    @Override
    public Multimap<Long, Long> collectEdges(final String type) throws IOException {
        final Multimap<Long, Long> edges = ArrayListMultimap.create();

        final String query = String.format("SELECT ?a ?b WHERE { ?a %s ?b }", RDFUtil.brackets(type));
        final BufferedReader reader = runQuery(query);

        // collecting ids
        final Pattern pattern = Pattern.compile("#x(.*?)>");
        String line;
        while ((line = reader.readLine()) != null) {
            final Matcher matcher = pattern.matcher(line);

            if (matcher.find()) {
                final String sourceString = matcher.group(1);
                if (matcher.find()) {
                    final String destinationString = matcher.group(1);
                    final Long source = new Long(sourceString);
                    final Long destination = new Long(destinationString);
                    edges.put(source, destination);
                }
            }
        }

        return edges;
    }

    @Override
    public Multimap<Long, String> collectProperties(final String type) throws IOException {
        final Multimap<Long, String> properties = ArrayListMultimap.create();

        final String query = String.format("SELECT ?a ?b WHERE { ?a %s ?b }", RDFUtil.brackets(type));
        final BufferedReader reader = runQuery(query);

        // example (tab-separated output)
        // @formatter:off
        // <http://www.semanticweb.org/ontologies/2011/1/TrainRequirementOntology.owl#x87947>   "653"^^<http://www.w3.org/2001/XMLSchema#int>
        // @formatter:on
        final String regex = "<.*x(\\d+)>\\t(.*)";
        final Pattern pattern = Pattern.compile(regex);

        String line;
        while ((line = reader.readLine()) != null) {
            final Matcher matcher = pattern.matcher(line);
            if (matcher.matches()) {
                final Long id = new Long(matcher.group(1));
                final String property = matcher.group(2);
                properties.put(id, property);
            }
        }
        return properties;
    }

}