DO NOT REPLY [Bug 17118] New: - XSLTInputHandler fails with InputSource and URL in constructor

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http://nagoya.apache.org/bugzilla/show_bug.cgi?id=17118

XSLTInputHandler fails with InputSource and URL in constructor

           Summary: XSLTInputHandler fails with InputSource and URL in
                    constructor
           Product: Fop
           Version: 0.20.5
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: Normal
          Priority: Other
         Component: general
        AssignedTo: fop-dev@xml.apache.org
        ReportedBy: i.pavkovic@bmiag.de


I noticed while using an XSLTInputHandler, that is does not work for other 
input sources than File:

String xmlURL = "test.xml", xslURL = "test.xsl";
XSLTInputHandler ih1 = new XSLTInputHandler(xmlURL,xmlURL);
XSLTInputHandler ih2 = new XSLTInputHandler(new InputSource(xmlURL),new 
InputSource(xslURL));
XSLTInputHandler ih3 = new XSLTInputHandler(new File(xmlURL),new File(xslURL));
Driver d = new Driver();
d.render(ih1.getParser(),ih1.getInputSource()); // fails!
d.render(ih2.getParser(),ih2.getInputSource()); // fails!
d.render(ih3.getParser(),ih3.getInputSource()); // works!

The failures are NullPointerExceptions. I assume, that TraxInputHandler.java 
(which is the delegation of XSLTInputHandler) is not fully compliant with other 
sources than file. Here is a version of TraxInpuHandler that should work.

/*
 * $Id: TraxInputHandler.java,v 1.1 2003/02/12 15:09:03 ilja Exp $
 * Copyright (C) 2001 The Apache Software Foundation. All rights reserved.
 * For details on use and redistribution please refer to the
 * LICENSE file included with these sources.
 */

package org.apache.fop.apps;

// Imported TraX classes
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.Transformer;
import javax.xml.transform.Source;
import javax.xml.transform.stream.StreamSource;
import javax.xml.transform.sax.SAXResult;
import javax.xml.transform.sax.SAXSource;
import javax.xml.transform.sax.SAXTransformerFactory;


// Imported SAX classes
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.XMLFilter;

// Imported java.io classes
import java.io.InputStream;
import java.io.IOException;
import java.io.File;

import org.apache.fop.apps.*;

/**
 * XSLTInputHandler basically takes an xmlfile and transforms it with an 
xsltfile
 * and the resulting xsl:fo document is input for Fop.
 */
public class TraxInputHandler extends InputHandler {
    private Transformer transformer;
    private StreamSource xmlSource;
    private StreamSource xsltSource;

    public TraxInputHandler(File xmlfile, File xsltfile)
      throws FOPException {
		xmlSource  = new StreamSource(xmlfile);
		xsltSource = new StreamSource(xsltfile);
		initTransformer();
    }

    public TraxInputHandler(String xmlURL, String xsltURL)
      throws FOPException {
        this.xmlSource  = new StreamSource(xmlURL);
        this.xsltSource = new StreamSource(xsltURL);
		initTransformer();
    }

    public TraxInputHandler(InputSource xmlSource, InputSource xsltSource) 
      throws FOPException {
        this.xmlSource  = new StreamSource(xmlSource.getByteStream(),
                                           xmlSource.getSystemId());
        this.xsltSource = new StreamSource(xsltSource.getByteStream(),
                                           xsltSource.getSystemId());
		initTransformer();
    }

	private void initTransformer() throws FOPException {
        try {
            transformer = TransformerFactory.newInstance().newTransformer
(xsltSource);
        }
        catch( Exception ex) {
            throw new FOPException(ex);
        }
	}

    /**
     * overwrites the method of the super class to return the xmlfile
     * @deprecated
     */
    public InputSource getInputSource() {
		InputSource is = new InputSource();
		is.setByteStream(xmlSource.getInputStream());
		is.setSystemId(xmlSource.getSystemId());
		return is;
    }

    /**
     * overwrites this method of the super class and returns an XMLFilter 
instead of a
     * simple XMLReader which allows chaining of transformations
     * @deprecated
     *
     */
    public XMLReader getParser() throws FOPException {
		return this.getXMLFilter(xsltSource);
    }

    /**
     * Creates from the transformer an instance of an XMLFilter which
     * then can be used in a chain with the XMLReader passed to Driver. This way
     * during the conversion of the xml file + xslt stylesheet the resulting
     * data is fed into Fop. This should help to avoid memory problems
     * @param xmlfile The xmlfile containing the text data
     * @param xsltfile An xslt stylesheet
     * @return XMLFilter an XMLFilter which can be chained together with other 
XMLReaders or XMLFilters
     */
    private static XMLFilter getXMLFilter(StreamSource xsltSource) throws 
FOPException {
        try {
            // Instantiate  a TransformerFactory.
            TransformerFactory tFactory = TransformerFactory.newInstance();
            // Determine whether the TransformerFactory supports The use uf 
SAXSource
            // and SAXResult
            if (tFactory.getFeature(SAXSource.FEATURE)
                    && tFactory.getFeature(SAXResult.FEATURE)) {
                // Cast the TransformerFactory to SAXTransformerFactory.
                SAXTransformerFactory saxTFactory =
                    ((SAXTransformerFactory)tFactory);
                // Create an XMLFilter for each stylesheet.
                XMLFilter xmlfilter =
                    saxTFactory.newXMLFilter(xsltSource);

                // Create an XMLReader.
                XMLReader parser = createParser();
                if (parser == null) {
                    throw new FOPException("Unable to create SAX parser");
                }

                // xmlFilter1 uses the XMLReader as its reader.
                xmlfilter.setParent(parser);
                return xmlfilter;
            } else {
                throw new FOPException("Your parser doesn't support the 
features SAXSource and SAXResult."
                                       + "\nMake sure you are using a xsl 
parser which supports TrAX");
            }
        } catch (FOPException fex) {
            throw fex;
        } catch (Exception ex) {
            throw new FOPException(ex);
        }
    }


    /**
     * Creates from the transformer an instance of an XMLFilter which
     * then can be used in a chain with the XMLReader passed to Driver. This way
     * during the conversion of the xml file + xslt stylesheet the resulting
     * data is fed into Fop. This should help to avoid memory problems
     * @param xmlfile The xmlfile containing the text data
     * @param xsltfile An xslt stylesheet
     * @return XMLFilter an XMLFilter which can be chained together with other 
XMLReaders or XMLFilters
     */
    public static XMLFilter getXMLFilter(File xmlfile,
                                         File xsltfile) throws FOPException {
		return getXMLFilter(new StreamSource(xsltfile));
    }

    public void run(Driver driver) throws FOPException {
        try {
            transformer.transform(xmlSource,
                                  new SAXResult(driver.getContentHandler()));
        } catch (Exception ex) {
            throw new FOPException(ex);
        }
    }

    public void setParameter(String name, Object value) {
        transformer.setParameter(name, value);
    }

}

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