Added DatasetGraphView
Project: http://git-wip-us.apache.org/repos/asf/incubator-commonsrdf/repo Commit: http://git-wip-us.apache.org/repos/asf/incubator-commonsrdf/commit/580484c9 Tree: http://git-wip-us.apache.org/repos/asf/incubator-commonsrdf/tree/580484c9 Diff: http://git-wip-us.apache.org/repos/asf/incubator-commonsrdf/diff/580484c9 Branch: refs/heads/master Commit: 580484c9d7d02d34b64e5276744c1f644dbbd2f2 Parents: 14e505e Author: Stian Soiland-Reyes <st...@apache.org> Authored: Tue Jun 14 16:44:24 2016 +0100 Committer: Stian Soiland-Reyes <st...@apache.org> Committed: Tue Jun 14 16:44:24 2016 +0100 ---------------------------------------------------------------------- .../commons/rdf/simple/DatasetGraphView.java | 138 +++++++++++++++++++ .../apache/commons/rdf/simple/DatasetImpl.java | 8 +- 2 files changed, 139 insertions(+), 7 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/incubator-commonsrdf/blob/580484c9/simple/src/main/java/org/apache/commons/rdf/simple/DatasetGraphView.java ---------------------------------------------------------------------- diff --git a/simple/src/main/java/org/apache/commons/rdf/simple/DatasetGraphView.java b/simple/src/main/java/org/apache/commons/rdf/simple/DatasetGraphView.java new file mode 100644 index 0000000..a347c3e --- /dev/null +++ b/simple/src/main/java/org/apache/commons/rdf/simple/DatasetGraphView.java @@ -0,0 +1,138 @@ +/** + * 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.commons.rdf.simple; + +import java.util.Optional; +import java.util.stream.Stream; + +import org.apache.commons.rdf.api.BlankNode; +import org.apache.commons.rdf.api.BlankNodeOrIRI; +import org.apache.commons.rdf.api.Dataset; +import org.apache.commons.rdf.api.Graph; +import org.apache.commons.rdf.api.IRI; +import org.apache.commons.rdf.api.Quad; +import org.apache.commons.rdf.api.RDFTerm; +import org.apache.commons.rdf.api.Triple; + +/** + * A {@link Graph} view on a {@link Dataset}. + * <p> + * This view is backed by a {@link Dataset}, and can be constructed in two ways: + * + * <dl> + * <dt>{@link #DatasetGraphView(Dataset)}</dt> + * <dd>Expose a <em>union graph</em> view of the Dataset, where all the + * {@link Quad}s of the Dataset is represented as a {@link Triple}. Adding + * triples will add them to the <em>default graph</em>, while removing triples + * will remove from all graphs.</dd> +* + * <dt>{@link #DatasetGraphView(Dataset, IRI)}</dt> + * <dd>Expose a particular graph of the Dataset, either named by an {@link IRI}, a + * {@link BlankNode}, or <code>null</code> for the <em>default graph</em>.</dd> + * </dl> + * <p> + * Changes in the Graph are reflected directly in the Dataset and vice versa. + * This class is thread-safe is the underlying Dataset is thread-safe. + */ +public class DatasetGraphView implements Graph { + + private final boolean unionGraph; + private final BlankNodeOrIRI namedGraph; + private final Dataset dataset; + + public DatasetGraphView(Dataset dataset) { + this.dataset = dataset; + this.namedGraph = null; + this.unionGraph = true; + } + + public DatasetGraphView(Dataset dataset, BlankNodeOrIRI namedGraph) { + this.dataset = dataset; + this.namedGraph = namedGraph; + this.unionGraph = false; + } + + @Override + public void close() throws Exception { + dataset.close(); + + } + + @Override + public void add(Triple triple) { + dataset.add(namedGraph, triple.getSubject(), triple.getPredicate(), triple.getObject()); + } + + @Override + public void add(BlankNodeOrIRI subject, IRI predicate, RDFTerm object) { + dataset.add(namedGraph, subject, predicate, object); + } + + @Override + public boolean contains(Triple triple) { + return dataset.contains(unionOrNamedGraph(), triple.getSubject(), triple.getPredicate(), triple.getObject()); + } + + private Optional<BlankNodeOrIRI> unionOrNamedGraph() { + if (unionGraph) { + return null; + } + return Optional.ofNullable(namedGraph); + } + + @Override + public boolean contains(BlankNodeOrIRI subject, IRI predicate, RDFTerm object) { + return dataset.contains(unionOrNamedGraph(), subject, predicate, object); + } + + @Override + public void remove(Triple triple) { + dataset.remove(unionOrNamedGraph(), triple.getSubject(), triple.getPredicate(), triple.getObject()); + } + + @Override + public void remove(BlankNodeOrIRI subject, IRI predicate, RDFTerm object) { + dataset.remove(unionOrNamedGraph(), subject, predicate, object); + } + + @Override + public void clear() { + dataset.remove(unionOrNamedGraph(), null, null, null); + } + + @Override + public long size() { + return stream().count(); + } + + @Override + public Stream<? extends Triple> stream() { + return stream(null, null, null); + } + + @Override + public Stream<? extends Triple> stream(BlankNodeOrIRI subject, IRI predicate, RDFTerm object) { + Stream<Triple> stream = dataset.stream(unionOrNamedGraph(), subject, predicate, object).map(Quad::asTriple); + if (unionGraph) { + // remove duplicates + return stream.distinct(); + } + return stream; + } + +} http://git-wip-us.apache.org/repos/asf/incubator-commonsrdf/blob/580484c9/simple/src/main/java/org/apache/commons/rdf/simple/DatasetImpl.java ---------------------------------------------------------------------- diff --git a/simple/src/main/java/org/apache/commons/rdf/simple/DatasetImpl.java b/simple/src/main/java/org/apache/commons/rdf/simple/DatasetImpl.java index 9de358f..c372012 100644 --- a/simple/src/main/java/org/apache/commons/rdf/simple/DatasetImpl.java +++ b/simple/src/main/java/org/apache/commons/rdf/simple/DatasetImpl.java @@ -204,13 +204,7 @@ final class DatasetImpl implements Dataset { @Override public Optional<Graph> getGraph(BlankNodeOrIRI graphName) { - // NOTE: Always returns a new copy - Graph g = new GraphImpl(factory); - stream(Optional.ofNullable(graphName), null, null, null) - .map(Quad::asTriple) - .sequential() - .forEach(g::add); - return Optional.of(g); + return Optional.of(new DatasetGraphView(this, graphName)); } @Override
