/*
* 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.mapreduce.transform;
import java.io.IOException;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.jena.graph.Node ;
import org.apache.jena.graph.Triple ;
import org.apache.jena.hadoop.rdf.types.QuadWritable;
import org.apache.jena.hadoop.rdf.types.TripleWritable;
import org.apache.jena.sparql.core.Quad ;
/**
* An abstract mapper which transforms triples into quads. Derived
* implementations may choose how the graph to which triples are assigned is
* decided.
* <p>
* Keys are left as is by this mapper.
* </p>
*
*
*
* @param <TKey>
*/
public abstract class AbstractTriplesToQuadsMapper<TKey> extends Mapper<TKey, TripleWritable, TKey, QuadWritable> {
@Override
protected final void map(TKey key, TripleWritable value, Context context) throws IOException, InterruptedException {
Triple triple = value.get();
Node graphNode = this.selectGraph(triple);
context.write(key, new QuadWritable(new Quad(graphNode, triple)));
}
/**
* Selects the graph name to use for converting the given triple into a quad
*
* @param triple
* Triple
* @return Tuple
*/
protected abstract Node selectGraph(Triple triple);
}