[
https://issues.apache.org/jira/browse/JENA-1391?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16310286#comment-16310286
]
ASF GitHub Bot commented on JENA-1391:
--------------------------------------
Github user ajs6f commented on a diff in the pull request:
https://github.com/apache/jena/pull/337#discussion_r159527929
--- Diff:
jena-arq/src/main/java/org/apache/jena/sparql/util/ViewDatasetGraph.java ---
@@ -0,0 +1,225 @@
+/*
+ * 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.util;
+
+import static java.util.Objects.requireNonNull;
+import static org.apache.jena.atlas.iterator.Iter.count;
+import static org.apache.jena.atlas.iterator.Iter.map;
+import static
org.apache.jena.ext.com.google.common.collect.Iterators.concat;
+import static org.apache.jena.graph.Node.ANY;
+import static org.apache.jena.query.ReadWrite.READ;
+import static org.apache.jena.sparql.core.Quad.defaultGraphIRI;
+import static org.apache.jena.sparql.util.graph.GraphUtils.triples2quads;
+
+import java.util.Iterator;
+
+import org.apache.jena.atlas.lib.Pair;
+import org.apache.jena.graph.Graph;
+import org.apache.jena.graph.Node;
+import org.apache.jena.graph.compose.MultiUnion;
+import org.apache.jena.query.ReadWrite;
+import org.apache.jena.shared.Lock;
+import org.apache.jena.sparql.core.DatasetGraph;
+import org.apache.jena.sparql.core.Quad;
+
+public abstract class ViewDatasetGraph extends
Pair.OfSameType<DatasetGraph> implements DatasetGraph {
+
+ private Context context;
+
+ private final Lock lock;
+
+ public ViewDatasetGraph(DatasetGraph left, DatasetGraph right, Context
c) {
+ super(requireNonNull(left), requireNonNull(right));
+ this.context = requireNonNull(c);
+ this.lock = new PairLock(left.getLock(), right.getLock());
+ }
+
+ protected static void throwNoMutationAllowed() {
+ throw new UnsupportedOperationException("This view does not allow
mutation!");
+ }
+
+ @Override
+ public void commit() {
+ throwNoMutationAllowed();
+ }
+
+ @Override
+ public void begin(ReadWrite readWrite) {
+ switch (readWrite) {
+ case WRITE:
+ throwNoMutationAllowed();
+ case READ:
+ forEach(dsg -> dsg.begin(READ));
--- End diff --
Done.
> Add Convenience Methods to Dataset
> ----------------------------------
>
> Key: JENA-1391
> URL: https://issues.apache.org/jira/browse/JENA-1391
> Project: Apache Jena
> Issue Type: Improvement
> Components: ARQ
> Affects Versions: Jena 3.4.0
> Reporter: Adam Jacobs
> Assignee: A. Soroka
> Priority: Trivial
>
> The Dataset interface could provide several convenience methods similar to
> the Model interface, allowing usability of RDF quads on par with RDF triples.
> Specific examples include,
> # add(Dataset)
> # remove(Dataset)
> # union(Dataset)
> # intersection(Dataset)
> # difference(Dataset)
> # isEmpty()
> Following is a possible implementation of these methods.
> {code:java}
> default Dataset add(Dataset d) {
> this.getDefaultModel().add(d.getDefaultModel());
> d.listNames().forEachRemaining(name ->
> this.getNamedModel(name).add(d.getNamedModel(name)));
> return this;
> }
> default Dataset remove(Dataset d) {
> this.getDefaultModel().remove(d.getDefaultModel());
> d.listNames().forEachRemaining(name ->
> this.getNamedModel(name).remove(d.getNamedModel(name)));
> return this;
> }
> default Dataset union(Dataset d) {
> return DatasetFactory.create().add(this).add(d);
> }
> default Dataset difference(Dataset d) {
> Dataset output = DatasetFactory.create();
>
> output.setDefaultModel(this.getDefaultModel().difference(d.getDefaultModel()));
> this.listNames().forEachRemaining(name -> {
> Model difference =
> this.getNamedModel(name).difference(d.getNamedModel(name));
> if (!difference.isEmpty()) output.addNamedModel(name, difference);
> });
> return output;
> }
> default Dataset intersection(Dataset d) {
> Dataset output = DatasetFactory.create();
>
> output.setDefaultModel(this.getDefaultModel().intersection(d.getDefaultModel()));
> Set<String> names = this.names();
> names.retainAll(d.names());
> names.forEach(name -> {
> Model intersection =
> this.getNamedModel(name).intersection(d.getNamedModel(name));
> if (!intersection.isEmpty()) output.addNamedModel(name,
> intersection);
> });
> return output;
> }
> default Set<String> names() {
> Set<String> names = new HashSet<>();
> this.listNames().forEachRemaining(names::add);
> return names;
> }
> default boolean isEmpty() {
> return this.asDatasetGraph().isEmpty();
> }
> {code}
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