001/*
002 * (C) Copyright 2006-2010 Nuxeo SAS (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 *     Nuxeo - initial API and implementation
016 *
017 * $Id$
018 */
019package org.nuxeo.ecm.platform.relations.core.listener;
020
021import java.util.List;
022
023import org.nuxeo.ecm.core.api.DocumentModel;
024import org.nuxeo.ecm.core.event.Event;
025import org.nuxeo.ecm.core.event.EventContext;
026import org.nuxeo.ecm.core.event.EventListener;
027import org.nuxeo.ecm.core.event.impl.DocumentEventContext;
028import org.nuxeo.ecm.platform.relations.api.Graph;
029import org.nuxeo.ecm.platform.relations.api.RelationManager;
030import org.nuxeo.ecm.platform.relations.api.Resource;
031import org.nuxeo.ecm.platform.relations.api.Statement;
032import org.nuxeo.ecm.platform.relations.api.util.RelationConstants;
033import org.nuxeo.runtime.api.Framework;
034
035/**
036 * Core Event listener that cleans relation on deleted documents; it should be executed after PublishRelationsListener
037 * so as to be able to copy relations from the deleted proxies.
038 *
039 * @author mcedica
040 */
041public class DeleteRelationsListener implements EventListener {
042
043    private RelationManager relationManager;
044
045    public void handleEvent(Event event) {
046        EventContext ctx = event.getContext();
047        if (ctx instanceof DocumentEventContext) {
048            DocumentEventContext docEventContext = (DocumentEventContext) ctx;
049            DocumentModel doc = docEventContext.getSourceDocument();
050            relationManager = getRelationManager();
051
052            // create resource from the document being deleted
053            Resource sourceResource = relationManager.getResource(RelationConstants.DOCUMENT_NAMESPACE, doc, null);
054
055            // remove all the relations from the default graf in which this
056            // document is an object in the statement
057            Graph graph = relationManager.getGraphByName(RelationConstants.GRAPH_NAME);
058            List<Statement> statementList = graph.getStatements(null, null, sourceResource);
059            graph.remove(statementList);
060
061            // remove all the relations in which this document is a subject in
062            // the statement
063            statementList = graph.getStatements(sourceResource, null, null);
064            graph.remove(statementList);
065        }
066    }
067
068    public RelationManager getRelationManager() {
069        if (relationManager == null) {
070            relationManager = Framework.getService(RelationManager.class);
071        }
072        return relationManager;
073    }
074
075}