Re: cannot find the namespace declarations from an extension function

I think that I have found an workaround :)
Instead of applying the transformation on a StreamSource object I am 
applying it on a DOMSource object and now the lookupNamespaceUri method 
works as expected.
Adrian.

Adrian Herscu wrote:
> Hi Michael and thanks for the response.
> Please see my comments between your lines.
> Regards,
> Adrian.
> 
> Michael Ludwig wrote:
> 
>>>     <gen:test func="lookupNamespaceUri">
>>
>> Now what's wrong with <xsl:value-of select="namespace-uri()"/> ?
>> No need to call an extension function here.
>>
>> To get the URIs for all the namespace nodes in scope, try:
>>
>>     <xsl:for-each select="namespace::node()">
>>       <NS><xsl:value-of select="."/></NS>
>>     </xsl:for-each>
>>
> 
> Please remember that this is just a simplified test case. My actual 
> problem is traversing relational data structures with less XSL code.
>  From the initial post:
> 
> <!-- key for looking up the wsdl:binding -->
> <variable name="binding-key">
>   <apply-templates select="." mode="binding-key" />
> </variable>
> 
> <for-each select="key('binding',$binding-key)">
> ...
> </for-each>
> 
> (this also requires some infrastructure code -- the definitions for the 
> keys and the templates; and these definitions are required for each 
> relational structure in the input model, so it is very easy to mess 
> things around resulting in hours of debugging)
> 
> Instead of that I was looking for an extension function that will enable 
> me to write something like that:
> <for-each select="myxslutils:ref(/wsdl:definitions/wsdl:binding,
>   'name', @binding, /wsdl:definitions/@targetNamespace)">
> ...
> </for-each>
> 
>>>       <!-- PROBLEM: works for 'wsdl' prefix,
>>>            for 'tns' and everything else,
>>>            e.g. 'soap', 'xsd', etc., returns null
>>>            -->
>>>       <value-of select="myext:lookupNamespaceUri(current(), 'tns')" />
>>
>> Note you don't need current() here, although there is no harm in doing
>> so. The current() function is used to get the context node *outside* an
>> XPath expression from inside that expression when moving away from the
>> context node, which you're not doing. So you can just use ".", the dot,
>> which is the context node (or context item in XSLT 2.0).
>>
>>>     public static String lookupNamespaceUri(final Node currentNode,
>>>             final String prefix) {
>>>         final String namespaceUri;
>>>
>>>         namespaceUri =
>>>             currentNode.getOwnerDocument().getDocumentElement()
>>>                 .lookupNamespaceURI(prefix);
>>>
>>>         return namespaceUri;
>>>     }
>>
>> I don't know why this doesn't return the expected result. A call to
>> getNodeName() works just fine.
>>
>> But then, maybe the expectation is wrong. An XSLT 1.0 processor isn't
>> obliged to respect your choice of prefixes for namespaces,
> 
> Hmmm... It appears that the parser completely ignores all 'xmlns' 
> attributes. The interesting thing is that it reads attributes from other 
> non-null namespaces.
> 
> Try to add a breakpoint on 
> http://svn.apache.org/viewvc/xalan/java/trunk/src/org/apache/xml/dtm/ref/DTMNodeProxy.java?view=markup 
> 
> line #1643
> 
>     public String lookupNamespaceURI(String specifiedPrefix) {
>     ...
>                 if (this.hasAttributes()) {
>                     NamedNodeMap map = this.getAttributes();
>                     int length = map.getLength();
>                     for (int i=0;i<length;i++) {
>     ...
> map.getLength returns 1 as if the 'targetNamespace' was the only 
> attribute. Tried to add
>   xmlns:foo="123"
>   foo:dummy="abc"
> to the wsdl:definitions and now the map.getLength returns 2 and the 
> foo:dummy attribute node node is recognized correctly.
> 
> 
> I tested this behavior with the Xerces parser, here is the test class:
> 
> package com.acme.apps;
> 
> import java.io.File;
> import java.io.IOException;
> 
> import javax.xml.parsers.DocumentBuilder;
> import javax.xml.parsers.DocumentBuilderFactory;
> import javax.xml.parsers.ParserConfigurationException;
> 
> import junit.framework.TestCase;
> 
> import org.w3c.dom.Document;
> import org.w3c.dom.Element;
> import org.xml.sax.SAXException;
> 
> public class XmlOperationsTest
>         extends TestCase {
> 
>     private static final String TEST_ROOT_DIR = "target/test-classes";
> 
>     private static final String TEST_XML =
>         "com/acme/apps/convert-temperature-service.wsdl";
> 
>     private static final File TEST_XML_FILE =
>         new File(TEST_ROOT_DIR, TEST_XML);
> 
>     public final void testLookupNamespaceUri()
>             throws ParserConfigurationException, SAXException,
>             IOException {
>         final DocumentBuilderFactory dbf =
>             DocumentBuilderFactory.newInstance();
>         dbf.setNamespaceAware(true);
>         final DocumentBuilder db = dbf.newDocumentBuilder();
>         final Document xml = db.parse(TEST_XML_FILE);
>         final Element documentElement = xml.getDocumentElement();
> 
>     /* NOTE: stepping inside the implementation of the method below
>     reveals that the 'xmlns:' prefixed attributes are counted as the
>     rest of attributes, which is different than the Xalan's parser
>     behavior. Therefore, I think this is a bug in Xalan. */
> 
>         final String tnsUri = documentElement.lookupNamespaceURI("tns");
> 
>         System.out.println(tnsUri);
> 
>         assertEquals("http://www.webserviceX.NET/", tnsUri);
>     }
> }
> 
>