[EMAIL PROTECTED] wrote:
>
> Hi Matt,
>
> Your error was not a fundamental error regarding XSLT. Rather, you were
> attempting to get at implementation classes by casting, which is always a
> bad thing to do. The implementations are hidden because you shouldn't rely
> on implementation-level behavior or APIs at the application level.
>
> XalanDocumentBuilder was designed as an abstraction to allow a source tree
> to be built through SAX events, rather than by parsing a document. You
> were mis-using it by casting to get at implementation classes.
>
> The other person was trying to modify the source tree, which is explicitly
> forbidden by the XSLT processing model. There is nothing in the XSLT
> recommendation that describes how this source tree is built, or any other
> such implementation-level details.
Well, actually what I was trying to do is to create new nodes and return
it as a nodeset.
I didn't mean to modify the XalanSourceTreeDocument object to which the
context node belongs to.
I've tried also to create another instance of XalanSourceTreeDocument
and invoke createTextNode(), but this also threw
NO_MODIFICATION_ALLOWED_ERR.
Which document class I can use to do such thing? Or is it completely
impossible?
I saw in Xalan-J's tokenize() function:
try
{
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
lDoc = db.newDocument();
}
catch(...) { ... }
NodeSet resultSet = new NodeSet();
while (lTokenizer.hasMoreTokens())
{
resultSet.addNode(lDoc.createTextNode(lTokenizer.nextToken()));
}
so I think it's also doable in Xalan C++.
rgds,
Edwin.
> Matthew James
> Hanson To:
> [email protected]
> <matthew.hanson@ cc: (bcc: David N
> Bertoni/CAM/Lotus)
> wcom.com> Subject: RE: createElement()
> inside external function
> segfaults
> 12/11/2001 02:13
> PM
>
>
>
> Using the SAX calls and const methods will be no problem! I assume, then,
> that my original strategy of building up a tree was actually a
> misunderstanding of XSLT, similar to the other post. What fundamental
> knowledge was I missing about XSLT?
>
> Thanks!
> Matt Hanson!
>
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]
> Sent: Tuesday, December 11, 2001 10:40 AM
> To: [email protected]
> Subject: RE: createElement() inside external function segfaults
>
> This is the exact same issue. XalanSourceTreeDocument does not support the
> standard DOM factory calls for creating nodes and modifying the tree. You
> need to build it through SAX events, because the tree must be built in
> document order. Allowing standard DOM calls would also allow random
> construction of the tree, which is not supported.
>
> Note that this does not affect _read-only_ access to the tree through DOM
> calls. This can be summarized by stating that most const methods of the
> XalanDOM hierarchy are supported, while _none_ of the non-const ones are
> supported.
>
> You can easily fix your code by calling the startElement() and endElement()
> member functions of XalanDocumentBuild, rather than creating a
> XalanSourceTreeElement instance and appending it.
>
> Dave
>
> Matthew James
> Hanson To:
> [email protected]
> <matthew.hanson@ cc: (bcc: David N
> Bertoni/CAM/Lotus)
> wcom.com> Subject: RE: createElement()
> inside external function
> segfaults
> 12/11/2001 11:53
> AM
>
> This issue may relate to a technique that I have been trying, but NOT part
> of an extension function. I have been trying to avoid using SAX events
> with
> XalanSourceTreeContentHandler. Rather, I was hoping I could have access to
> the underlying XalanSourceTreeDocument returned from
> XalanDefaultDocumentBuilder->getDocument(). No exceptions are thrown, but
> XalanSourceTreeDocument->createNodeElement(...) doesn't output my data.
> Here is the code:
>
> AttributesImpl attrs;
> XalanDOMString elemNm, attrNm, attrVal;
> const XalanDOMString attrType("CDATA");
>
> XalanDocumentBuilder* const docBldr =
> theXalanTransformer.createDocumentBuilder();
> if (docBldr)
> {
> XalanSourceTreeDocument * doc(static_cast <
> XalanSourceTreeDocument * >
> (docBldr->getDocument()));
> if (doc)
> {
> std::cout << "have
> XalanSourceTreeDocument\n";
> elemNm = "name1";
> attrNm = "attr1Nm";
> attrVal = "attr1Val";
> attrs.addAttribute(c_wstr(attrNm),
> c_wstr(attrType), c_wstr(attrVal));
> attrNm = "attr2Nm";
> attrVal = "attr2Val";
> attrs.addAttribute(c_wstr(attrNm),
> c_wstr(attrType), c_wstr(attrVal));
> XalanSourceTreeElement *
> element(doc->createElementNode(attrNm.c_str(),
> attrs));
> doc->appendChildNode(element);
> }
> }
>
> Am I also misunderstanding the usage of these classes. I hope really hope
> to have access to the underlying tree so that I can get attributes, values,
> of an element to be used by its child elements.
>
> Thanks!!!
>
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]
> Sent: Tuesday, December 11, 2001 9:30 AM
> To: [email protected]
> Subject: Re: createElement() inside external function segfaults
>
> It's not a bug in Xalan, it's a bug in your application and your
> understanding of XSLT.
>
> You are not allowed to modify the source tree in any way, including
> creating new nodes. The function you're calling is throwing an exception
> which you're not catching. See the class XalanDOMException and the source
> code for XalanSourceTreeDocument for more information on what's being
> thrown.
>
> Currently, there's no way in Xalan-C to create new nodes in an extension
> function. We can certainly make something like that available, but it
> wouldn't be through DOM APIs. Insteand, it would be through getting a SAX
> handler and sending events. If this functionality is important to you,
> then we should discuss the best way to implement this.
>
> Dave
>
> Edwin Pratomo
> <[EMAIL PROTECTED] To:
> [email protected]
> .org> cc:
> Sent by: Subject: createElement()
> inside external function segfaults
> [EMAIL PROTECTED]
> m
>
> 12/11/2001 09:56
> AM
>
> Hi,
>
> I tried to create new elements inside an external function, but
> createElement() segfaults:
>
> virtual XObjectPtr
> execute(
> XPathExecutionContext& executionContext,
> XalanNode* context,
> int /* opPos */,
> const XObjectArgVectorType& args)
> {
> XalanDocument *doc = context->getOwnerDocument();
> XalanElement *new_node = doc->createElement(XalanDOMString("foo"));
> ...
>
> Is this a bug? any workaround?
>
> rgds,
> Edwin.
>
> --
> CPAN home: http://search.cpan.org/search?author=edpratomo
--
CPAN home: http://search.cpan.org/search?author=edpratomo
