Hi Hernando,
FormatterToXML does not generate namespace declarations. Unfortunately,
it's not working from the nodes themselves -- it's just getting events
describing the nodes. For it to do what you want, it would have to keep
track of namespace declarations that are already in-scope, and emit
namespace declarations in the serialized XML when necessary.
That code would be fairly complex, and doesn't really fit in within the
event driven model of the serializers. When we move the serializers to the
SAX2 interfaces, we may be able to solve this problem more easily, but I
don't know how long that will take. However, code could be written in the
FormatterTreeWalker to handle this. That's where it really belongs,
because the walker is working with the nodes themselves.
Unfortunately, we have a SerializeNodeSet sample program which implies this
is possible. That's my fault -- I wrote that sample without thinking of
the implications of generating namespace declarations when necessary.
So, I suggest you create an enhancement request in Bugzilla and we can look
at figuring out what it would take to do this.
Dave
[EMAIL PROTECTED]
oftware.com To:
[email protected]
cc: (bcc: David N
Bertoni/Cambridge/IBM)
04/25/2003 07:28 AM Subject: Problem with
namespaces
Hi,
I'm experiencing a problem with an extension function that I implemented to
serialize the content of a set of nodes. I'm using the FormatterToXML class
in the Xalan API to produce XML text from a node set. The problem I'm
having is that the formatter looses all the namespace information in the
original document. The original prefixes are kept and that only makes
things worse because after the serialization takes place the result is not
well-formed. I was hoping it was only a matter of setting up some parameter
but I can't seem to make it work. The code of the serialization function
is:
XObjectPtr XMLNodeSerializer::execute(XPathExecutionContext&
executionContext,
XalanNode* context,
const XObjectArgVectorType& args,
const Locator* locator) const {
// Return an empty string if the arguments don't match.
if ((args.size() != 1) || args[0].null()) {
return executionContext.getXObjectFactory()
.createString(XalanDOMString(""));
}
const NodeRefListBase *nodeList = &args[0]->nodeset();
const NodeRefList::size_type nodeListLength = nodeList->getLength();
if (nodeListLength == 0) {
return executionContext.getXObjectFactory()
.createString(XalanDOMString(""));
}
XMLByteStream& outputStream = _stage.getStrStream();
XMLNodeSerializer* thisObject = const_cast<XMLNodeSerializer*>(this);
_stage.getStrStream().reset();
XalanTransformerOutputStream xalanOutputStream(thisObject, &write);
XalanOutputStreamPrintWriter streamWriter(xalanOutputStream);
FormatterToXML formatter(streamWriter, // Use our
stream writer
XalanDOMString(), // Use the
default version
false, // Indent the
output
0, // Indentation
size if 4 characters
XalanDOMString(NODE_ENCODING)); // Enconde the
result in UTF-16
if (_stage.isChunkFormattingEnabled()) {
formatter.setDoIndent(true);
formatter.setIndent(INDENTATION_SIZE);
}
// Don't write a header...
formatter.setShouldWriteXMLHeader(false);
formatter.setEscapeCData(false);
formatter.setStripCData(false);
// It's required that we do this...
formatter.startDocument();
FormatterTreeWalker treeWalker(formatter);
// Traverse the subtree of the document rooted at
// each node we've selected...
for (NodeRefList::size_type i = 0; i < nodeListLength; ++i) {
const XalanNode* const theNode = nodeList->item(i);
assert(theNode != 0);
const XalanNode::NodeType theNodeType =
theNode->getNodeType();
if (theNodeType != XalanNode::ATTRIBUTE_NODE) {
treeWalker.traverseSubtree(theNode);
}
}
// It's required that we do this...
formatter.endDocument();
// Make sure that the stream is NULL terminated;
XalanDOMChar nullChar = 0;
outputStream.write(&nullChar, sizeof(XalanDOMChar));
size_t serializedNodeLength = 0;
const char* serializedNode =
(const char*)outputStream.getContent(serializedNodeLength);
// When building the result string skip the byte order mark bytes.
return executionContext.getXObjectFactory()
.createString(XalanDOMString((const
XalanDOMChar*)(serializedNode+2)));
}
If I serialize the root element (asset:assetList) of the following
document:
<?xml version="1.0" encoding="UTF-8"?>
<asset:assetList xmlns:asset="http://www.cust.org/Asset"; xmlns:xsi="
http://www.w3.org/2001/XMLSchema-instance"; xsi:schemaLocation="
http://www.cust.org/Asset
I:\development\documentation\training\xmlpack\BestPractices\examples\asset.xsd"
xmlns:bla="
http://www.bla.com/BlaBlaBla";>
<asset:asset name="ASCL" xmlns:bla="http://www.bla.com/YadiYadiYa";>
<asset:assetDescription
type="short">Ascential</asset:assetDescription>
<asset:assetDescription type="long">Ascential Software
Corporation</asset:assetDescription>
<bla:bla>BlaBlaBla</bla:bla>
</asset:asset>
<asset:asset name="MSFT">
<asset:assetDescription
type="short">Microsoft</asset:assetDescription>
<asset:assetDescription type="long">Microsoft
Corporation</asset:assetDescription>
</asset:asset>
<asset:asset name="ORCL">
<asset:assetDescription
type="short">Oracle</asset:assetDescription>
<asset:assetDescription type="long">Oracle
Corporation</asset:assetDescription>
</asset:asset>
</asset:assetList>
I get:
<asset:assetList xsi:schemaLocation="http://www.cust.org/Asset
I:\development\documentation\training\xmlpack\BestPractices\examples\asset.xsd"
xmlns:xml="
http://www.w3.org/XML/1998/namespace";>
<asset:asset name="ASCL">
<asset:assetDescription
type="short">Ascential</asset:assetDescription>
<asset:assetDescription type="long">Ascential Software
Corporation</asset:assetDescription>
<bla:bla>BlaBlaBla</bla:bla>
</asset:asset>
<asset:asset name="MSFT">
<asset:assetDescription
type="short">Microsoft</asset:assetDescription>
<asset:assetDescription type="long">Microsoft
Corporation</asset:assetDescription>
</asset:asset>
<asset:asset name="ORCL">
<asset:assetDescription
type="short">Oracle</asset:assetDescription>
<asset:assetDescription type="long">Oracle
Corporation</asset:assetDescription>
</asset:asset>
</asset:assetList>
I assume the result is correct since I'm creating a new document and then
copying the node set to it, but my questions is. Do you have an idea of how
can I keep the namespace information? I was thinking of going to the
extreme of subclassing the FormatterTreeWalker class and keep track of
prefixes/namespaces as it walks the node list and force the namespace
information where it is first used. Would you suggest something different?
Many thanks,
Hernando Borda
Software Developer
Ascential Software Corp.
