| /* |
| * 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.any23.writer; |
| |
| import org.apache.any23.configuration.Settings; |
| import org.apache.any23.extractor.ExtractionContext; |
| import org.apache.any23.rdf.RDFUtils; |
| import org.eclipse.rdf4j.model.Resource; |
| import org.eclipse.rdf4j.model.IRI; |
| import org.eclipse.rdf4j.model.Value; |
| import org.eclipse.rdf4j.rio.RDFHandlerException; |
| import org.eclipse.rdf4j.rio.RDFWriter; |
| import org.eclipse.rdf4j.rio.RDFWriterFactory; |
| import org.eclipse.rdf4j.rio.WriterConfig; |
| |
| import java.io.BufferedWriter; |
| import java.io.Flushable; |
| import java.io.IOException; |
| import java.io.OutputStream; |
| import java.io.OutputStreamWriter; |
| import java.nio.charset.Charset; |
| import java.util.Locale; |
| import java.util.Optional; |
| |
| /** |
| * A {@link TripleHandler} that writes |
| * triples to a Sesame {@link org.eclipse.rdf4j.rio.RDFWriter}, |
| * eg for serialization using one of Sesame's writers. |
| * |
| * @author Richard Cyganiak (richard@cyganiak.de) |
| * @author Michele Mostarda (mostarda@fbk.eu) |
| * @author Hans Brende (hansbrende@apache.org) |
| */ |
| public abstract class RDFWriterTripleHandler extends TripleWriterHandler implements FormatWriter { |
| |
| private RDFWriter _writer; |
| private boolean writerStarted; |
| private final Flushable out; |
| private final TripleFormat format; |
| |
| /** |
| * The annotation flag. |
| */ |
| private boolean annotated = false; |
| |
| static TripleFormat format(RDFWriterFactory rdf4j) { |
| return TripleFormat.of(rdf4j.getRDFFormat()); |
| } |
| |
| RDFWriterTripleHandler(RDFWriterFactory rdf4j, TripleFormat format, OutputStream out, Settings settings) { |
| this.format = format; |
| Optional<Charset> charset = format.getCharset(); |
| RDFWriter w; |
| if (!charset.isPresent()) { |
| this.out = out; |
| w = _writer = rdf4j.getWriter(out); |
| } else { |
| //use buffered writer if format supports encoding |
| BufferedWriter buf = new BufferedWriter(new OutputStreamWriter(out, charset.get())); |
| this.out = buf; |
| w = _writer = rdf4j.getWriter(buf); |
| } |
| configure(w.getWriterConfig(), settings); |
| } |
| |
| abstract void configure(WriterConfig config, Settings settings); |
| |
| RDFWriter writer() throws TripleHandlerException { |
| RDFWriter w = _writer; |
| if (w == null) { |
| throw new TripleHandlerException("writer has been closed!"); |
| } |
| if (!writerStarted) { |
| writerStarted = true; |
| try { |
| w.startRDF(); |
| } catch (RDFHandlerException e) { |
| throw new TripleHandlerException("Error while starting document", e); |
| } |
| } |
| return w; |
| } |
| |
| /** |
| * If <code>true</code> then the produced <b>RDF</b> is annotated with |
| * the extractors used to generate the specific statements. |
| * |
| * @return the annotation flag value. |
| */ |
| @Override |
| public boolean isAnnotated() { |
| return annotated; |
| } |
| |
| /** |
| * Sets the <i>annotation</i> flag. |
| * |
| * @param f If <code>true</code> then the produced <b>RDF</b> is annotated with |
| * the extractors used to generate the specific statements. |
| */ |
| @Override |
| public void setAnnotated(boolean f) { |
| annotated = f; |
| } |
| |
| @Override |
| public void startDocument(IRI documentIRI) throws TripleHandlerException { |
| handleComment("OUTPUT FORMAT: " + format); |
| } |
| |
| @Override |
| public void openContext(ExtractionContext context) throws TripleHandlerException { |
| handleComment("BEGIN: " + context ); |
| } |
| |
| @Override |
| public void writeTriple(Resource s, IRI p, Value o, Resource g) |
| throws TripleHandlerException { |
| try { |
| writer().handleStatement(RDFUtils.quad(s, p, o, g)); |
| } catch (RDFHandlerException ex) { |
| throw new TripleHandlerException( |
| String.format(Locale.ROOT, "Error while receiving triple: %s %s %s %s", s, p, o, g), |
| ex |
| ); |
| } |
| } |
| |
| @Override |
| public void writeNamespace(String prefix, String uri) |
| throws TripleHandlerException { |
| try { |
| writer().handleNamespace(prefix, uri); |
| } catch (RDFHandlerException ex) { |
| throw new TripleHandlerException(String.format(Locale.ROOT, "Error while receiving namespace: %s:%s", prefix, uri), |
| ex |
| ); |
| } |
| } |
| |
| @Override |
| public void closeContext(ExtractionContext context) throws TripleHandlerException { |
| handleComment( "END: " + context ); |
| } |
| |
| @Override |
| public void close() throws TripleHandlerException { |
| RDFWriter writer = _writer; |
| if (writer == null) { |
| return; |
| } |
| _writer = null; |
| try { |
| if (!writerStarted) { |
| writer.startRDF(); |
| } |
| writer.endRDF(); //calls flush() |
| } catch (RDFHandlerException e) { |
| throw new TripleHandlerException("Error closing writer", e); |
| } |
| } |
| |
| @Override |
| public void endDocument(IRI documentIRI) throws TripleHandlerException { |
| try { |
| out.flush(); |
| } catch (IOException e) { |
| throw new TripleHandlerException("Error ending document", e); |
| } |
| } |
| |
| private void handleComment(String comment) throws TripleHandlerException { |
| if( !annotated ) return; |
| try { |
| writer().handleComment(comment); |
| } catch (RDFHandlerException rdfhe) { |
| throw new TripleHandlerException("Error while handing comment.", rdfhe); |
| } |
| } |
| } |