ParseUtils.java

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/*
 * Gridarta MMORPG map editor for Crossfire, Daimonin and similar games.
 * Copyright (C) 2000-2023 The Gridarta Developers.
 *
 * 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 2 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, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
package net.sf.gridarta.utils.xml;
 
import java.io.IOException;
import java.io.InputStream;
import java.net.URISyntaxException;
import java.net.URL;
import nu.xom.Builder;
import nu.xom.DocType;
import nu.xom.Document;
import nu.xom.ParsingException;
import nu.xom.xinclude.XIncludeException;
import nu.xom.xinclude.XIncluder;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import org.xml.sax.ErrorHandler;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.XMLReaderFactory;
 
public class ParseUtils {
 
    private ParseUtils() {
    }
 
    @NotNull
    public static Document readXmlUrl(@NotNull final URL url, @NotNull final String rootElement, @NotNull final String systemId, @NotNull final String resourceName, @Nullable final ErrorHandler errorHandler) throws IOException, ParsingException, SAXException, URISyntaxException, XIncludeException {
        try (InputStream inputStream = url.openStream()) {
            return readXmlStream(inputStream, url.toURI().toASCIIString(), rootElement, systemId, resourceName, errorHandler);
        }
    }
 
    @NotNull
    private static Document readXmlStream(@NotNull final InputStream inputStream, @NotNull final String baseURI, @NotNull final String rootElement, @NotNull final String systemId, @NotNull final String resourceName, @Nullable final ErrorHandler errorHandler) throws IOException, ParsingException, SAXException, XIncludeException {
        final XMLReader xmlReader = XMLReaderFactory.createXMLReader();
        xmlReader.setEntityResolver(new FixedDtdEntityResolver(systemId, resourceName));
        if (errorHandler != null) {
            xmlReader.setErrorHandler(errorHandler);
        }
        final Builder builder = new Builder(xmlReader, true);
        final Document document;
        try (InputStream in2 = new FixedDtdInputStream(inputStream, rootElement, systemId)) {
            document = builder.build(in2, baseURI);
        }
        final DocType docType = document.getDocType();
        if (docType == null) {
            // using a FixedDtdInputStream ensures that a DOCTYPE declaration exists
            throw new AssertionError("document contains no DOCTYPE declaration");
        }
        final String documentSystemId = docType.getSystemID();
        if (documentSystemId == null) {
            throw new ParsingException("DOCTYPE declaration has no system ID; expecting '" + systemId + "'");
        }
        if (!documentSystemId.equals(systemId)) {
            throw new ParsingException("system ID in DOCTYPE declaration is '" + documentSystemId + "'; expecting '" + systemId + "'");
        }
        final String documentRootElement = docType.getRootElementName();
        if (!documentRootElement.equals(rootElement)) {
            throw new ParsingException("root element in DOCTYPE declaration is '" + documentRootElement + "'; expecting '" + rootElement + "'");
        }
        XIncluder.resolveInPlace(document, builder);
        return document;
    }
 
}