| /* |
| * 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.jena.tdb2.store; |
| |
| import java.nio.file.Path; |
| import java.util.concurrent.atomic.AtomicReference; |
| |
| import org.apache.jena.atlas.lib.Cache; |
| import org.apache.jena.atlas.lib.CacheFactory; |
| import org.apache.jena.dboe.base.file.Location; |
| import org.apache.jena.graph.Graph; |
| import org.apache.jena.graph.Node; |
| import org.apache.jena.sparql.core.DatasetGraph; |
| import org.apache.jena.sparql.core.DatasetGraphWrapper; |
| import org.apache.jena.sparql.core.Quad; |
| |
| final |
| public class DatasetGraphSwitchable extends DatasetGraphWrapper |
| { |
| // QueryEngineFactoryWrapper has a QueryEngineFactory that is always loaded that |
| // executes on the unwrapped DSG (recursively). Unwrapping is via getBase, calling |
| // getWrapped() which is implemented with get(). |
| |
| // static { |
| // // QueryEngineRegistry.addFactory(factory()); |
| // } |
| |
| private final AtomicReference<DatasetGraph> dsgx = new AtomicReference<>(); |
| // Null for in-memory datasets. |
| private final Path basePath; |
| private final Location location; |
| |
| public DatasetGraphSwitchable(Path base, Location location, DatasetGraph dsg) { |
| // Don't use the slot in datasetGraphWrapper - use the AtomicReference |
| super(null, dsg.getContext()); |
| dsgx.set(dsg); |
| this.basePath = base; |
| this.location = location; |
| } |
| |
| /** Is this {@code DatasetGraphSwitchable} just a holder for a {@code DatasetGraph}? |
| * If so, it does not have a location on disk. |
| */ |
| public boolean hasContainerPath() { return basePath != null; } |
| |
| public Path getContainerPath() { return basePath; } |
| |
| public Location getLocation() { return location; } |
| |
| /** The dataset to use for redirection - can be overridden. |
| * It is also guaranteed that this is called only once per |
| * delegated call. Changes to the wrapped object can be |
| * made based on that contract. |
| */ |
| @Override |
| public DatasetGraph get() { return dsgx.get(); } |
| |
| /** Set the base {@link DatasetGraph}. |
| * Returns the old value. |
| */ |
| public DatasetGraph set(DatasetGraph dsg) { |
| return dsgx.getAndSet(dsg); |
| } |
| |
| /** Don't do anything on close. |
| * This would not be safe across switches. |
| */ |
| @Override |
| public void close() {} |
| |
| // /** Don't do anything on sync. */ |
| // @Override |
| // public void sync() { } |
| |
| /** If and only if the current value is the given old value, set the base {@link DatasetGraph} |
| * Returns true if a swap happened. |
| */ |
| public boolean change(DatasetGraph oldDSG, DatasetGraph newDSG) { |
| // No need to clear. ngCache.clear(); |
| return dsgx.compareAndSet(oldDSG, newDSG); |
| } |
| |
| private Graph dftGraph = GraphViewSwitchable.createDefaultGraphSwitchable(this); |
| |
| @Override |
| public Graph getDefaultGraph() { |
| return dftGraph; |
| } |
| |
| @Override |
| public Graph getUnionGraph() { |
| return GraphViewSwitchable.createUnionGraphSwitchable(this); |
| } |
| |
| // private Cache<Node, Graph> ngCache = CacheFactory.createCache(10); |
| private Cache<Node, Graph> ngCache = CacheFactory.createOneSlotCache(); |
| |
| @Override |
| public Graph getGraph(Node gn) { |
| Node key = ( gn != null ) ? gn : Quad.defaultGraphNodeGenerated; |
| return ngCache.getOrFill(key, ()->GraphViewSwitchable.createNamedGraphSwitchable(this, key)); |
| } |
| } |
| |