/*
* 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.hadoop.rdf.io.output;
import java.io.IOException;
import java.io.Writer;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.mapreduce.RecordWriter;
import org.apache.jena.graph.Triple ;
import org.apache.jena.hadoop.rdf.io.registry.HadoopRdfIORegistry;
import org.apache.jena.hadoop.rdf.types.TripleWritable;
import org.apache.jena.riot.Lang;
import org.apache.jena.riot.RDFLanguages;
/**
* An output format for RDF triples that dynamically selects the appropriate triple
* writer to use based on the file extension of the output file.
* <p>
* For example this is useful when the output format may be controlled by a user
* supplied filename i.e. the desired RDF output format is not precisely known
* in advance
* </p>
*
* @param <TKey>
* Key type
*/
public abstract class TriplesOutputFormat<TKey> extends AbstractNodeTupleOutputFormat<TKey, Triple, TripleWritable> {
@Override
protected RecordWriter<TKey, TripleWritable> getRecordWriter(Writer writer, Configuration config, Path outputPath) throws IOException {
Lang lang = RDFLanguages.filenameToLang(outputPath.getName());
if (lang == null)
throw new IOException("There is no registered RDF language for the output file " + outputPath.toString());
if (!RDFLanguages.isTriples(lang)) throw new IOException(
lang.getName()
+ " is not a RDF triples format, perhaps you wanted QuadsOutputFormat or TriplesOrQuadsOutputFormat instead?");
// This will throw an appropriate error if the language does not support writing triples
return HadoopRdfIORegistry.<TKey>createTripleWriter(lang, writer, config);
}
}