001/*
002 * (C) Copyright 2006-2010 Nuxeo SA (http://nuxeo.com/) and others.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 *
016 * Contributors:
017 *     Nuxeo - initial API and implementation
018 *
019 * $Id$
020 */
021package org.nuxeo.ecm.platform.relations.core.listener;
022
023import java.util.List;
024
025import org.nuxeo.ecm.core.api.DocumentModel;
026import org.nuxeo.ecm.core.event.Event;
027import org.nuxeo.ecm.core.event.EventContext;
028import org.nuxeo.ecm.core.event.EventListener;
029import org.nuxeo.ecm.core.event.impl.DocumentEventContext;
030import org.nuxeo.ecm.platform.relations.api.Graph;
031import org.nuxeo.ecm.platform.relations.api.RelationManager;
032import org.nuxeo.ecm.platform.relations.api.Resource;
033import org.nuxeo.ecm.platform.relations.api.Statement;
034import org.nuxeo.ecm.platform.relations.api.util.RelationConstants;
035import org.nuxeo.runtime.api.Framework;
036
037/**
038 * Core Event listener that cleans relation on deleted documents; it should be executed after PublishRelationsListener
039 * so as to be able to copy relations from the deleted proxies.
040 *
041 * @author mcedica
042 */
043public class DeleteRelationsListener implements EventListener {
044
045    private RelationManager relationManager;
046
047    public void handleEvent(Event event) {
048        EventContext ctx = event.getContext();
049        if (ctx instanceof DocumentEventContext) {
050            DocumentEventContext docEventContext = (DocumentEventContext) ctx;
051            DocumentModel doc = docEventContext.getSourceDocument();
052            relationManager = getRelationManager();
053
054            // create resource from the document being deleted
055            Resource sourceResource = relationManager.getResource(RelationConstants.DOCUMENT_NAMESPACE, doc, null);
056
057            // remove all the relations from the default graf in which this
058            // document is an object in the statement
059            Graph graph = relationManager.getGraphByName(RelationConstants.GRAPH_NAME);
060            List<Statement> statementList = graph.getStatements(null, null, sourceResource);
061            graph.remove(statementList);
062
063            // remove all the relations in which this document is a subject in
064            // the statement
065            statementList = graph.getStatements(sourceResource, null, null);
066            graph.remove(statementList);
067        }
068    }
069
070    public RelationManager getRelationManager() {
071        if (relationManager == null) {
072            relationManager = Framework.getService(RelationManager.class);
073        }
074        return relationManager;
075    }
076
077}