| /* |
| * 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.sparql.core; |
| |
| import java.util.Iterator; |
| |
| import org.apache.jena.atlas.iterator.Iter; |
| import org.apache.jena.graph.Graph; |
| import org.apache.jena.graph.Node; |
| import org.apache.jena.query.ReadWrite; |
| import org.apache.jena.query.TxnType; |
| |
| /** A {@link DatasetGraph} class for support of {@link DatasetGraph DatasetGraphs} that do nothing. |
| * <ul> |
| * <li>No named graphs. |
| * <li>Empty default graph. |
| * <li>Empty union graph. |
| * <li>No update. ({@link DatasetGraphSink} overrides this) |
| * </ul> |
| * |
| * @see DatasetGraphSink |
| * @see DatasetGraphZero |
| */ |
| public abstract class DatasetGraphNull extends DatasetGraphBaseFind { |
| protected abstract Graph createGraph(); |
| private Graph dftGraph = createGraph(); |
| private Graph unionGraph = createGraph(); |
| |
| protected DatasetGraphNull() {} |
| |
| private Transactional txn = TransactionalNull.create(); |
| @Override public void begin() { txn.begin(); } |
| @Override public void begin(TxnType txnType) { txn.begin(txnType); } |
| @Override public void begin(ReadWrite mode) { txn.begin(mode); } |
| @Override public boolean promote(Promote txnType) { return txn.promote(txnType); } |
| @Override public void commit() { txn.commit(); } |
| @Override public void abort() { txn.abort(); } |
| @Override public boolean isInTransaction() { return txn.isInTransaction(); } |
| @Override public void end() { txn.end(); } |
| @Override public ReadWrite transactionMode() { return txn.transactionMode(); } |
| @Override public TxnType transactionType() { return txn.transactionType(); } |
| @Override public boolean supportsTransactions() { return true; } |
| @Override public boolean supportsTransactionAbort() { return true; } |
| |
| @Override |
| public Iterator<Node> listGraphNodes() { |
| return Iter.nullIterator(); |
| } |
| |
| @Override |
| protected Iterator<Quad> findInDftGraph(Node s, Node p, Node o) { |
| return Iter.nullIterator(); |
| } |
| |
| @Override |
| protected Iterator<Quad> findInSpecificNamedGraph(Node g, Node s, Node p, Node o) { |
| return Iter.nullIterator(); |
| } |
| |
| @Override |
| protected Iterator<Quad> findInAnyNamedGraphs(Node s, Node p, Node o) { |
| return Iter.nullIterator(); |
| } |
| |
| @Override |
| public Graph getDefaultGraph() { |
| return dftGraph; |
| } |
| |
| @Override |
| public Graph getUnionGraph() { |
| return unionGraph; |
| } |
| |
| @Override |
| public Graph getGraph(Node graphNode) { |
| if ( Quad.isDefaultGraph(graphNode) ) |
| return dftGraph; |
| if ( Quad.isUnionGraph(graphNode) ) |
| return getUnionGraph(); |
| return null; |
| } |
| |
| @Override |
| public void add(Quad quad) { unsupportedMethod(this, "add") ; } |
| |
| @Override |
| public void delete(Quad quad) { unsupportedMethod(this, "delete") ; } |
| |
| @Override |
| public void deleteAny(Node g, Node s, Node p, Node o) { |
| unsupportedMethod(this, "deleteAny"); |
| } |
| |
| @Override |
| public void setDefaultGraph(Graph g) { |
| unsupportedMethod(this, "setDefaultGraph"); |
| } |
| |
| @Override |
| public void addGraph(Node graphName, Graph graph) { |
| unsupportedMethod(this, "addGraph"); |
| } |
| |
| @Override |
| public void removeGraph(Node graphName) { |
| unsupportedMethod(this, "removeGraph"); |
| } |
| } |