On 11/7/2016 11:31 PM, Langer, Christoph wrote:
Hi Joe,
thanks for your comments.
Yes the customer does not really want to insert a null value but
create an empty text node. So they’ll fix their code anyway.
However, I thought it would be a good Idea to make the Serializer more
robust with regards to such null data. Especially given that it’s
possible via the DOM API to construct such null nodes. So I take you
support this endeavor?
Sure. Some null-checks are welcome.
Thanks,
Joe
Thanks
Christoph
*From:*huizhe wang [mailto:[email protected]]
*Sent:* Dienstag, 8. November 2016 06:01
*To:* Langer, Christoph <[email protected]>; Aleks Efimov
<[email protected]>; Lance Andersen <[email protected]>
*Cc:* [email protected]
*Subject:* Re: XALAN: Text node of value 'null' - Is this illegal or
does XSLTC have an issue here?
Looks like a null check-in is desirable. If the intention is to add a
text node, which I assume was his intention, he wouldn't want a null
node. If the intention is to create an empty element, then he didn't
need the line that added the null text node.
As far as DOM goes, it would have been better if it was clearer on how
null be handled (a DOMException probably). But for a 10+ yr old API,
the case is not enough to call for a change of the behavior.
Thanks,
Joe
On 11/7/2016 8:09 AM, Langer, Christoph wrote:
Hi Xalan experts,
I’ve recently handled a customer issue about Text Nodes of value
‘null’ inside a DOM, causing an exception during XALAN XSLT
transformation. The repro case is quite simple. Consider the
following small Java sample [1] which creates a DOM from a very
basic XML, inserts a text node with value null into the DOM and
then runs an identity transformation on it. Without inserting the
null Text node, it would run without issues. However, the
com.sun.org.apache.xml.internal.serializer.ToUnknownStream class
stumbles over the null value and the transformation throws an NPE
[2]. I believe this could be easily fixed by adding a null check
in the serializer and handling null like “”. However, would you
agree that it is a real issue worth fixing or should one rather
stress the point that Text Nodes of null are illegal? (Is that
true, anyway? Didn’t find any specification about that…) Please
let me know your opinion – and if you agree I would work on a fix.
Thanks in advance for comments
Christoph
[1] Sample code:
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.xml.sax.SAXException;
public class TestTransformWithNullText {
public static void main(String[] args) throws
ParserConfigurationException, SAXException, IOException,
TransformerException {
// create a small DOM
DocumentBuilder db =
DocumentBuilderFactory.newInstance().newDocumentBuilder();
Document doc = db.parse(new ByteArrayInputStream("<?xml
version=\"1.0\"?><DOCROOT/>".getBytes()));
// insert a bad element
Element e = doc.createElement("ERROR");
e.appendChild(doc.createTextNode(null));
doc.getDocumentElement().appendChild(e);
// transform
ByteArrayOutputStream bos = new ByteArrayOutputStream();
TransformerFactory.newInstance().newTransformer().transform(
new DOMSource(doc.getDocumentElement()), new StreamResult(bos));
System.out.println(bos);
}
}
[2] Exception encountered:
Exception in thread "main"
javax.xml.transform.TransformerException:
java.lang.NullPointerException
at
com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform([email protected]/TransformerImpl.java:789
<mailto:[email protected]/TransformerImpl.java:789>)
at
com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform([email protected]/TransformerImpl.java:376
<mailto:[email protected]/TransformerImpl.java:376>)
at
com.sap.cl.xml.test.transform.TestTransformWithNullText.main(TestTransformWithNullText.java:33)
Caused by: java.lang.NullPointerException
at
com.sun.org.apache.xml.internal.serializer.ToUnknownStream.characters([email protected]/ToUnknownStream.java:342
<mailto:[email protected]/ToUnknownStream.java:342>)
at
com.sun.org.apache.xalan.internal.xsltc.trax.DOM2TO.parse([email protected]/DOM2TO.java:244
<mailto:[email protected]/DOM2TO.java:244>)
at
com.sun.org.apache.xalan.internal.xsltc.trax.DOM2TO.parse([email protected]/DOM2TO.java:230
<mailto:[email protected]/DOM2TO.java:230>)
at
com.sun.org.apache.xalan.internal.xsltc.trax.DOM2TO.parse([email protected]/DOM2TO.java:230
<mailto:[email protected]/DOM2TO.java:230>)
at
com.sun.org.apache.xalan.internal.xsltc.trax.DOM2TO.parse([email protected]/DOM2TO.java:94
<mailto:[email protected]/DOM2TO.java:94>)
at
com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transformIdentity([email protected]/TransformerImpl.java:718
<mailto:[email protected]/TransformerImpl.java:718>)
at
com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform([email protected]/TransformerImpl.java:780
<mailto:[email protected]/TransformerImpl.java:780>)
... 2 more
---------
java.lang.NullPointerException
at
com.sun.org.apache.xml.internal.serializer.ToUnknownStream.characters([email protected]/ToUnknownStream.java:342
<mailto:[email protected]/ToUnknownStream.java:342>)
at
com.sun.org.apache.xalan.internal.xsltc.trax.DOM2TO.parse([email protected]/DOM2TO.java:244
<mailto:[email protected]/DOM2TO.java:244>)
at
com.sun.org.apache.xalan.internal.xsltc.trax.DOM2TO.parse([email protected]/DOM2TO.java:230
<mailto:[email protected]/DOM2TO.java:230>)
at
com.sun.org.apache.xalan.internal.xsltc.trax.DOM2TO.parse([email protected]/DOM2TO.java:230
<mailto:[email protected]/DOM2TO.java:230>)
at
com.sun.org.apache.xalan.internal.xsltc.trax.DOM2TO.parse([email protected]/DOM2TO.java:94
<mailto:[email protected]/DOM2TO.java:94>)
at
com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transformIdentity([email protected]/TransformerImpl.java:718
<mailto:[email protected]/TransformerImpl.java:718>)
at
com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform([email protected]/TransformerImpl.java:780
<mailto:[email protected]/TransformerImpl.java:780>)
at
com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform([email protected]/TransformerImpl.java:376
<mailto:[email protected]/TransformerImpl.java:376>)
at
com.sap.cl.xml.test.transform.TestTransformWithNullText.main(TestTransformWithNullText.java:33)
