hoot.services.controllers.osm.ChangesetUploadXmlValidator.java Source code

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Here is the source code for hoot.services.controllers.osm.ChangesetUploadXmlValidator.java

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/*
 * This file is part of Hootenanny.
 *
 * Hootenanny 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/>.
 *
 * --------------------------------------------------------------------
 *
 * The following copyright notices are generated automatically. If you
 * have a new notice to add, please use the format:
 * " * @copyright Copyright ..."
 * This will properly maintain the copyright information. DigitalGlobe
 * copyrights will be updated automatically.
 *
 * @copyright Copyright (C) 2016 DigitalGlobe (http://www.digitalglobe.com/)
 */
package hoot.services.controllers.osm;

import javax.xml.transform.TransformerException;

import org.apache.commons.lang3.StringUtils;
import org.apache.xpath.XPathAPI;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.w3c.dom.Document;

import hoot.services.utils.XmlDocumentBuilder;

/**
 * OSM changeset validator
 */
final class ChangesetUploadXmlValidator {
    private static final Logger logger = LoggerFactory.getLogger(ChangesetUploadXmlValidator.class);

    private ChangesetUploadXmlValidator() {
    }

    /**
     * Validates a changeset
     * 
     * @param changesetXml
     *            an OSM changeset for reviewed items
     */
    static Document parseAndValidate(String changesetXml) {
        Document changesetDiffDoc;
        try {
            logger.debug("Parsing changeset diff XML: {}", StringUtils.abbreviate(changesetXml, 1000));
            changesetDiffDoc = XmlDocumentBuilder.parse(changesetXml);
        } catch (Exception e) {
            throw new RuntimeException(
                    "Error parsing changeset diff data: " + changesetXml + " (" + e.getMessage() + ")", e);
        }

        try {
            if (XPathAPI.selectNodeList(changesetDiffDoc, "//osmChange").getLength() > 1) {
                throw new IllegalArgumentException("Only one changeset may be uploaded at a time.");
            }
        } catch (TransformerException e) {
            throw new RuntimeException("Error invoking XPathAPI!", e);
        }

        if (!changesetHasElements(changesetDiffDoc)) {
            throw new IllegalArgumentException("No items in uploaded changeset.");
        }

        return changesetDiffDoc;
    }

    /**
     * Determines whether a changeset DOM has any elements in it. (Strangely, I
     * couldn't figure out how to do this correctly with XPath).
     * 
     * @param changesetDiffDoc
     *            the changeset to check for elements
     * @return true if the changeset has elements; false otherwise
     */
    private static boolean changesetHasElements(Document changesetDiffDoc) {
        return (changesetDiffDoc.getElementsByTagName("node").getLength()
                + changesetDiffDoc.getElementsByTagName("way").getLength()
                + changesetDiffDoc.getElementsByTagName("relation").getLength()) > 0;
    }
}