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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.io;

/*-
 * #%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 xyz.ottr.lutra.bottr.model.InstanceMap;
import xyz.ottr.lutra.bottr.parser.BInstanceMapParser;
import xyz.ottr.lutra.model.Instance;
import xyz.ottr.lutra.parser.InstanceParser;
import xyz.ottr.lutra.system.Result;
import xyz.ottr.lutra.system.ResultStream;
import xyz.ottr.lutra.wottr.io.RDFIO;

public class BInstanceReader implements InstanceParser {

    @Override
    public ResultStream apply(String file) {
                
        if (getInstanceStream(file).getStream().count() == 0) {
            return ResultStream.of(Result.error("Error reading BOTTR file: '" + file + "'"));
        } else {
            return getInstanceStream(file);
        }
            
    }
    
    private ResultStream getInstanceStream(String file) {
        return ResultStream.innerOf(file)
                .innerFlatMap(RDFIO.fileReader())
                .innerFlatMap(new BInstanceMapParser(file))
                .innerFlatMap(InstanceMap::get);
    }

}