de.uzk.hki.da.model.RightsSectionURNMetsXmlReader.java Source code

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Here is the source code for de.uzk.hki.da.model.RightsSectionURNMetsXmlReader.java

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/*
  DA-NRW Software Suite | ContentBroker
  Copyright (C) 2013 Historisch-Kulturwissenschaftliche Informationsverarbeitung
  Universitt zu Kln
    
  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 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 Public License for more details.
    
  You should have received a copy of the GNU General Public License
  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package de.uzk.hki.da.model;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.text.ParseException;

import javax.xml.parsers.SAXParserFactory;

import org.apache.commons.io.input.BOMInputStream;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.xml.sax.ErrorHandler;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import org.xml.sax.XMLReader;

import de.uzk.hki.da.metadata.PremisXmlReaderNodeFactory;
import nu.xom.Attribute;
import nu.xom.Builder;
import nu.xom.Document;
import nu.xom.Element;
import nu.xom.Elements;
import nu.xom.NodeFactory;
import nu.xom.ParsingException;
import nu.xom.ValidityException;

/**
 * The Class MetsURNXmlReader.
 *
 * @author Thomas Kleinke
 */
public class RightsSectionURNMetsXmlReader {

    /** The Constant METS_NS. */
    private static final String METS_NS = "http://www.loc.gov/METS/";

    /** The Constant MODS_NS. */
    private static final String MODS_NS = "http://www.loc.gov/mods/v3";

    /** The logger. */
    private static Logger logger = LoggerFactory.getLogger(RightsSectionURNMetsXmlReader.class);

    /** The err. */
    private static ErrorHandler err = new ErrorHandler() {

        @Override
        public void error(SAXParseException e) throws SAXException {
            throw new SAXException("Error while parsing mets file", e);
        }

        @Override
        public void fatalError(SAXParseException e) throws SAXException {
            throw new SAXException("Fatal error while parsing mets file", e);
        }

        @Override
        public void warning(SAXParseException e) throws SAXException {
            logger.warn("Warning while parsing mets file", e);
        }
    };

    /**
     * Read urn.
     *
     * @param file the file
     * @return The URN specified in the METS file or null if the METS file doesn't specify an URN
     * @throws IOException Signals that an I/O exception has occurred.
     * @throws ParseException the parse exception
     * @author Thomas Kleinke
     */
    public String readURN(File file) throws IOException, ParseException {

        FileInputStream fileInputStream = new FileInputStream(file);
        BOMInputStream bomInputStream = new BOMInputStream(fileInputStream);

        XMLReader xmlReader = null;
        SAXParserFactory spf = SAXParserFactory.newInstance();
        try {
            xmlReader = spf.newSAXParser().getXMLReader();
        } catch (Exception e) {
            fileInputStream.close();
            bomInputStream.close();
            throw new IOException("Error creating SAX parser", e);
        }
        xmlReader.setErrorHandler(err);
        NodeFactory nodeFactory = new PremisXmlReaderNodeFactory();
        Builder parser = new Builder(xmlReader, false, nodeFactory);
        logger.trace("Successfully built builder and XML reader");

        try {
            String urn = null;

            Document doc = parser.build(bomInputStream);
            Element root = doc.getRootElement();

            Element dmdSecEl = root.getFirstChildElement("dmdSec", METS_NS);
            if (dmdSecEl == null)
                return null;

            Element mdWrapEl = dmdSecEl.getFirstChildElement("mdWrap", METS_NS);
            if (mdWrapEl == null)
                return null;

            Element xmlDataEl = mdWrapEl.getFirstChildElement("xmlData", METS_NS);
            if (xmlDataEl == null)
                return null;

            Element modsEl = xmlDataEl.getFirstChildElement("mods", MODS_NS);
            if (modsEl == null)
                return null;

            Elements identifierEls = modsEl.getChildElements("identifier", MODS_NS);
            for (int i = 0; i < identifierEls.size(); i++) {
                Element element = identifierEls.get(i);
                Attribute attribute = element.getAttribute("type");
                if (attribute.getValue().toLowerCase().equals("urn"))
                    urn = element.getValue();
            }

            if (urn != null && urn.equals(""))
                urn = null;

            return urn;
        } catch (ValidityException ve) {
            throw new IOException(ve);
        } catch (ParsingException pe) {
            throw new IOException(pe);
        } catch (IOException ie) {
            throw new IOException(ie);
        } finally {
            fileInputStream.close();
            bomInputStream.close();
        }
    }
}