Package org.exist.xquery.functions.fn

Source Code of org.exist.xquery.functions.fn.ParsingFunctions

/*
*  eXist Open Source Native XML Database
*  Copyright (C) 2001-09 The eXist Project
*  http://exist-db.org
*  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
*  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 Lesser General Public License for more details.
*  You should have received a copy of the GNU Lesser General Public License
*  along with this program; if not, write to the Free Software
*  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*  $Id$
*/
package org.exist.xquery.functions.fn;

import org.apache.log4j.Logger;
import org.exist.Namespaces;
import org.exist.dom.QName;
import org.exist.memtree.DocumentImpl;
import org.exist.memtree.MemTreeBuilder;
import org.exist.memtree.NodeImpl;
import org.exist.memtree.SAXAdapter;
import org.exist.validation.ValidationReport;
import org.exist.xquery.*;
import org.exist.xquery.functions.validation.Shared;
import org.exist.xquery.value.FunctionParameterSequenceType;
import org.exist.xquery.value.FunctionReturnSequenceType;
import org.exist.xquery.value.NodeValue;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.Type;
import org.exist.xquery.value.ValueSequence;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import java.io.IOException;
import java.io.StringReader;

public class ParsingFunctions extends BasicFunction {

  protected static final FunctionReturnSequenceType RESULT_TYPE_FOR_PARSE_XML = new FunctionReturnSequenceType(Type.DOCUMENT,
      Cardinality.ZERO_OR_ONE, "the parsed document");
  protected static final FunctionReturnSequenceType RESULT_TYPE_FOR_PARSE_XML_FRAGMENT = new FunctionReturnSequenceType(Type.ELEMENT,
      Cardinality.ZERO_OR_MORE, "the parsed document fragment")

  protected static final FunctionParameterSequenceType TO_BE_PARSED_PARAMETER = new FunctionParameterSequenceType(
      "arg", Type.STRING, Cardinality.ZERO_OR_ONE, "The string to be parsed");

  protected static final Logger logger = Logger.getLogger(ParsingFunctions.class);

  public final static FunctionSignature signatures[] = {
      new FunctionSignature(
          new QName("parse-xml", Function.BUILTIN_FUNCTION_NS),
          "This function takes as input an XML document represented as a string,"
              + " and returns the document node at the root of an XDM tree representing the parsed document.",
          new SequenceType[] { TO_BE_PARSED_PARAMETER }, RESULT_TYPE_FOR_PARSE_XML),
      new FunctionSignature(
          new QName("parse-xml-fragment", Function.BUILTIN_FUNCTION_NS),
          "This function takes as input an XML external entity represented as a string," +
          "and returns the document node at the root of an XDM tree representing the parsed document fragment.",
          new SequenceType[] { TO_BE_PARSED_PARAMETER }, RESULT_TYPE_FOR_PARSE_XML_FRAGMENT) };

  public ParsingFunctions(XQueryContext context, FunctionSignature signature) {
    super(context, signature);
  }

  public Sequence eval(Sequence[] args, Sequence contextSequence) throws XPathException {
   
    Sequence resultSequence;

    if (args[0].getItemCount() == 0) {
      return Sequence.EMPTY_SEQUENCE;
    }
    String xmlContent = args[0].itemAt(0).getStringValue();
    if (xmlContent.length() == 0) {
      return Sequence.EMPTY_SEQUENCE;
    }

    if (isCalledAs("parse-xml-fragment")) {
      xmlContent = "<root>" + xmlContent + "</root>";
    }
   
    final StringReader reader = new StringReader(xmlContent);
        final InputSource src = new InputSource(reader);
       
        return parse(src, context, args);
  }

    private Sequence parse(final InputSource src, XQueryContext theContext, Sequence[] args) throws XPathException {
        Sequence resultSequence;
        final ValidationReport report = new ValidationReport();
        final SAXAdapter adapter = new SAXAdapter(theContext);
        try {
            final SAXParserFactory factory = SAXParserFactory.newInstance();
            factory.setNamespaceAware(true);
                     
            XMLReader xr = null;
           
            if (xr == null) {
                final SAXParser parser = factory.newSAXParser();
                xr = parser.getXMLReader();
            }
           
            xr.setErrorHandler(report);
            xr.setContentHandler(adapter);
            xr.setProperty(Namespaces.SAX_LEXICAL_HANDLER, adapter);
            xr.parse(src);
           
        } catch (final ParserConfigurationException e) {
            throw new XPathException(this, ErrorCodes.EXXQDY0002, "Error while constructing XML parser: "  + e.getMessage(), args[0], e);
        } catch (final SAXException e) {
            logger.debug("Error while parsing XML: " + e.getMessage(), e);
        } catch (final IOException e) {
            throw new XPathException(this, ErrorCodes.FODC0006, ErrorCodes.FODC0006.getDescription() + ": " + e.getMessage(),
                    args[0], e);
        }
       
        if (report.isValid()) {
            if (isCalledAs("parse-xml-fragment")) {
                resultSequence = new ValueSequence();
                NodeList children = adapter.getDocument().getDocumentElement().getChildNodes();
                for (int i = 0, il = children.getLength(); i < il; i++) {
                    Node child = children.item(i);
                    resultSequence.add((NodeValue)child);
                }
               
                return resultSequence;
            } else {
                return (DocumentImpl) adapter.getDocument();
            }
        } else {
            final MemTreeBuilder builder = theContext.getDocumentBuilder();
            final NodeImpl result = Shared.writeReport(report, builder);
            throw new XPathException(this, ErrorCodes.FODC0006, ErrorCodes.FODC0006.getDescription() + ": " + report.toString(), result);
        }
    }
}
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