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This Lutra submodule implements bOTTR (https://spec.ottr.xyz/bOTTR/0.1/). bOTTR is a mapping language for transforming data from relational databases, triplestores, CSV-files and other sources, into instances of templates. Lutra is the reference implementation of the OTTR framework. For more information about OTTR, see http://ottr.xyz.

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package xyz.ottr.lutra.bottr.source;

/*-
 * #%L
 * lutra-bottr
 * %%
 * Copyright (C) 2018 - 2019 University of Oslo
 * %%
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 2.1 of the
 * License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Lesser Public License for more details.
 * 
 * You should have received a copy of the GNU General Lesser Public
 * License along with this program.  If not, see
 * .
 * #L%
 */

import java.util.Collections;
import java.util.List;
import org.apache.jena.query.QueryExecution;
import org.apache.jena.query.QueryExecutionFactory;
import org.apache.jena.rdf.model.Model;
import org.apache.jena.rdf.model.ModelFactory;
import org.apache.jena.shared.PrefixMapping;
import xyz.ottr.lutra.system.Result;
import xyz.ottr.lutra.system.ResultStream;
import xyz.ottr.lutra.wottr.io.RDFIO;

public class RDFFileSource extends AbstractSPARQLSource {

    private final List modelURIs;

    public RDFFileSource(PrefixMapping prefixes, List modelURIs) {
        super(prefixes);
        this.modelURIs = Collections.unmodifiableList(modelURIs);
    }

    public RDFFileSource(List modelURIs) {
        this(PrefixMapping.Factory.create(), modelURIs);
    }

    private Result loadModels() {
        return ResultStream.innerOf(this.modelURIs)
                .innerFlatMap(RDFIO.fileReader())
                .aggregate()
                .map(stream -> stream.reduce(
                    ModelFactory.createDefaultModel(),
                    Model::add));
    }

    @Override
    protected Result getQueryExecution(String query) {
        return Result.zip(
            super.getQuery(query),
            loadModels(),
            QueryExecutionFactory::create);
    }

}