org.apache.jena.lang.csv.ReaderRIOTCSV Maven / Gradle / Ivy

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jena-csv is for getting CSVs into a form that is amenable to Jena SPARQL processing, and doing so in a way that is not specific to CSV files. It includes getting the right architecture in place for regular table shaped data, using the core abstraction of PropertyTable.

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/**
 * 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.lang.csv;

import java.io.InputStream;
import java.io.Reader;
import java.util.ArrayList;
import java.util.List;

import org.apache.jena.atlas.csv.CSVParser;
import org.apache.jena.atlas.lib.IRILib ;
import org.apache.jena.atlas.web.ContentType;
import org.apache.jena.datatypes.xsd.XSDDatatype ;
import org.apache.jena.graph.Node ;
import org.apache.jena.graph.NodeFactory ;
import org.apache.jena.riot.ReaderRIOT;
import org.apache.jena.riot.system.*;
import org.apache.jena.sparql.util.Context;

public class ReaderRIOTCSV implements ReaderRIOT {
    
    public static final String CSV_PREFIX = "http://w3c/future-csv-vocab/";
	public static final String CSV_ROW = CSV_PREFIX + "row";

	private InputStream input = null;
	private Reader reader = null;
	private String base;
	private String filename;
	private StreamRDF sink;
	private ParserProfile maker;

	public ReaderRIOTCSV(ErrorHandler errorHandler) {
		this.maker = RiotLib.createParserProfile(errorHandler);
	}

	@Override
    public void read(InputStream in, String baseURI, ContentType ct, StreamRDF output, Context context) {
	    this.input = in;
        this.reader = null;
        this.base = baseURI;
        this.filename = baseURI;
        this.sink = output;
	    parse();
	}

    @Override
    public void read(Reader reader, String baseURI, ContentType ct, StreamRDF output, Context context) {
        this.input = null;
        this.reader = reader;
        this.base = baseURI;
        this.filename = baseURI;
        this.sink = output;
        parse();
    }

	public void parse() {
		sink.start();
		CSVParser parser = (input != null) ? CSVParser.create(input) : CSVParser.create(reader);
		ArrayList predicates = new ArrayList<>();
		int rowNum = 0;
		for (List row : parser) {
			
			if (rowNum == 0) {
				for (String column : row) {
					String uri = IRIResolver.resolveString(filename) + "#"
							+ toSafeLocalname(column);
					Node predicate = this.maker.createURI(uri, rowNum, 0);
					predicates.add(predicate);
				}
			} else {
				//Node subject = this.profile.createBlankNode(null, -1, -1);
				Node subject = calculateSubject(rowNum, filename);
				Node predicateRow = this.maker.createURI(CSV_ROW, -1, -1);
				Node objectRow = this.maker.createTypedLiteral((rowNum + ""), XSDDatatype.XSDinteger, rowNum, 0);
				sink.triple(this.maker.createTriple(subject, predicateRow, objectRow, rowNum, 0));
				for (int col = 0; col < row.size() && col