| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| package org.apache.clerezza.platform.graphprovider.content; |
| |
| import java.util.Arrays; |
| import java.util.HashSet; |
| import java.util.Set; |
| import java.util.concurrent.locks.ReentrantReadWriteLock; |
| import org.apache.clerezza.platform.Constants; |
| |
| import org.osgi.service.component.ComponentContext; |
| import org.apache.clerezza.rdf.core.MGraph; |
| import org.apache.clerezza.rdf.core.TripleCollection; |
| import org.apache.clerezza.rdf.core.UriRef; |
| import org.apache.clerezza.rdf.core.access.LockableMGraph; |
| import org.apache.clerezza.rdf.core.access.NoSuchEntityException; |
| import org.apache.clerezza.rdf.core.access.TcManager; |
| import org.apache.clerezza.rdf.utils.UnionMGraph; |
| |
| /** |
| * A service providing a method to retrieve a <code>UnionGraph</code> containing |
| * the ContentGraph and additional graphs. |
| * |
| * Over the Configuration Admin Service additional graphs can be added |
| * permanently. With the methods <code>addTemporaryAdditionGraph</code> and |
| * <code>removeTemporaryAdditionGraph</code> graphs can be added temporarily. |
| * Temporarily means that after restarting the org.apache.clerezza.platform.graphprovider.content |
| * bundle, these graphs will no longer be returned in the <code>UnionGraph</code>. |
| * |
| * @scr.component |
| * @scr.service interface="org.apache.clerezza.platform.graphprovider.content.ContentGraphProvider" |
| * |
| * @author rbn, mir |
| */ |
| public class ContentGraphProvider { |
| |
| |
| /** |
| * Service property header, which contains the URIs of additional |
| * <code>TripleCollection</code>s that are united as read-only to the Graph |
| * returned by <code>getContentGraph</code> |
| * |
| * @scr.property name="additions" values.name="" description="Contains |
| * additional TripleCollections that are added to the content |
| * graph for reading" |
| */ |
| public static final String CONTENT_ADDITIONS = "additions"; |
| |
| /** |
| * @scr.reference |
| */ |
| private TcManager tcManager; |
| |
| |
| |
| /** |
| * The URIs of the read-only addition-<code>TripleCollection</code>s |
| */ |
| private UriRef[] additions; |
| |
| private ReentrantReadWriteLock configLock = new ReentrantReadWriteLock(); |
| |
| protected void activate(ComponentContext context) { |
| GraphNameTransitioner.renameGraphsWithOldNames(tcManager); |
| try { |
| tcManager.getMGraph(Constants.CONTENT_GRAPH_URI); |
| } catch (NoSuchEntityException nsee) { |
| tcManager.createMGraph(Constants.CONTENT_GRAPH_URI); |
| } |
| String[] additionUriStrings = (String[]) context.getProperties().get( |
| CONTENT_ADDITIONS); |
| additions = new UriRef[additionUriStrings.length]; |
| for (int i = 0; i < additionUriStrings.length; i++) { |
| additions[i] = new UriRef(additionUriStrings[i]); |
| |
| } |
| } |
| |
| public LockableMGraph getContentGraph() { |
| configLock.readLock().lock(); |
| try { |
| TripleCollection[] united = new TripleCollection[additions.length + 1]; |
| int i = 0; |
| united[i++] = tcManager.getMGraph(Constants.CONTENT_GRAPH_URI); |
| for (UriRef uriRef : additions) { |
| united[i++] = tcManager.getTriples(uriRef); |
| } |
| return new UnionMGraph(united); |
| } finally { |
| configLock.readLock().unlock(); |
| } |
| } |
| |
| public void addTemporaryAdditionGraph(UriRef graphName) { |
| configLock.writeLock().lock(); |
| try { |
| Set<UriRef> additionsSet = new HashSet<UriRef>(Arrays |
| .asList(additions)); |
| additionsSet.add(graphName); |
| additions = additionsSet.toArray(new UriRef[additionsSet.size()]); |
| } finally { |
| configLock.writeLock().unlock(); |
| } |
| } |
| |
| public void removeTemporaryAdditionGraph(UriRef graphName) { |
| configLock.writeLock().lock(); |
| try { |
| Set<UriRef> additionsSet = new HashSet<UriRef>(Arrays |
| .asList(additions)); |
| additionsSet.remove(graphName); |
| additions = additionsSet.toArray(new UriRef[additionsSet.size()]); |
| } finally { |
| configLock.writeLock().unlock(); |
| } |
| } |
| } |