001/*
002 * (C) Copyright 2011 Nuxeo SA (http://nuxeo.com/) and contributors.
003 *
004 * All rights reserved. This program and the accompanying materials
005 * are made available under the terms of the GNU Lesser General Public License
006 * (LGPL) version 2.1 which accompanies this distribution, and is available at
007 * http://www.gnu.org/licenses/lgpl.html
008 *
009 * This library is distributed in the hope that it will be useful,
010 * but WITHOUT ANY WARRANTY; without even the implied warranty of
011 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
012 * Lesser General Public License for more details.
013 *
014 * Contributors:
015 *     Florent Guillaume
016 */
017package org.nuxeo.ecm.platform.relations.jena;
018
019import org.apache.commons.logging.Log;
020import org.apache.commons.logging.LogFactory;
021import org.nuxeo.ecm.core.api.CoreSession;
022import org.nuxeo.ecm.platform.relations.CoreGraphFactory;
023import org.nuxeo.ecm.platform.relations.api.Graph;
024import org.nuxeo.ecm.platform.relations.api.GraphDescription;
025import org.nuxeo.ecm.platform.relations.api.GraphFactory;
026import org.nuxeo.ecm.platform.relations.services.RelationService;
027import org.nuxeo.runtime.api.Framework;
028
029/**
030 * A factory that detects if a Jena graph or a core graph should be used, and remembers it for future invocations.
031 * <p>
032 * A Jena graph is used if it contains at least one relation for the given graph.
033 */
034public class JenaOrCoreGraphFactory implements GraphFactory {
035
036    private static final Log log = LogFactory.getLog(JenaOrCoreGraphFactory.class);
037
038    // used for tests
039    protected static JenaGraph testJenaGraph;
040
041    @Override
042    public Graph createGraph(GraphDescription graphDescription, CoreSession session) {
043        RelationService service = (RelationService) Framework.getRuntime().getComponent(RelationService.NAME);
044        String name = graphDescription.getName();
045
046        Graph graph;
047        if (testJenaGraph == null) {
048            graph = new JenaGraph();
049        } else {
050            // test mode, allows reuse of in-memory graph
051            graph = testJenaGraph;
052        }
053        graph.setDescription(graphDescription);
054        if (graph.size().longValue() > 0) {
055            // Jena graph already contains data, use it
056            service.graphFactories.remove(name);
057            service.graphRegistry.put(name, graph);
058            log.info("Graph " + name + " using Jena");
059        } else {
060            // use a core graph and remember this factory
061            GraphFactory factory = new CoreGraphFactory();
062            service.graphFactories.put(name, factory);
063            graph = factory.createGraph(graphDescription, session);
064            log.info("Graph " + name + " using Core");
065        }
066        return graph;
067    }
068
069}