/**
* Extension element for piping an XML document through a series of 1 or more transformations.
*
* <pre>Common usage pattern: A stylesheet transforms a listing of documents to be
* transformed into a TOC. For each document in the listing calls the pipeDocument
* extension element to pipe that document through a series of 1 or more stylesheets
* to the desired output document.
*
* Syntax:
* <xsl:stylesheet version="1.0"
* xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
* xmlns:pipe="http://xml.apache.org/xalan/PipeDocument"
* extension-element-prefixes="pipe">
* ...
* <pipe:pipeDocument source="source.xml" target="target.xml">
* <stylesheet href="ss1.xsl">
* <param name="param1" value="value1"/>
* </stylesheet>
* <stylesheet href="ss2.xsl">
* <param name="param1" value="value1"/>
* <param name="param2" value="value2"/>
* </stylesheet>
* <stylesheet href="ss1.xsl"/>
* </pipe:pipeDocument>
*
* Notes:</pre>
*
* <ul>
* <li>The base URI for the source attribute is the XML "listing" document.
* <li/>
* <li>The target attribute is taken as is (base is the current user directory).
* <li/>
* <li>The stylsheet containg the extension element is the base URI for the stylesheet hrefs.
* <li/>
* </ul>
*/
public void pipeDocument(XSLProcessorContext context, ElemExtensionCall elem)
throws TransformerException, TransformerConfigurationException, SAXException, IOException,
FileNotFoundException {
SAXTransformerFactory saxTFactory = (SAXTransformerFactory) TransformerFactory.newInstance();
// XML doc to transform.
String source = elem.getAttribute("source", context.getContextNode(), context.getTransformer());
TransformerImpl transImpl = context.getTransformer();
// Base URI for input doc, so base for relative URI to XML doc to transform.
String baseURLOfSource = transImpl.getBaseURLOfSource();
// Absolute URI for XML doc to transform.
String absSourceURL = SystemIDResolver.getAbsoluteURI(source, baseURLOfSource);
// Transformation target
String target = elem.getAttribute("target", context.getContextNode(), context.getTransformer());
XPathContext xctxt = context.getTransformer().getXPathContext();
int xt = xctxt.getDTMHandleFromNode(context.getContextNode());
// Get System Id for stylesheet; to be used to resolve URIs to other stylesheets.
String sysId = elem.getSystemId();
NodeList ssNodes = null;
NodeList paramNodes = null;
Node ssNode = null;
Node paramNode = null;
if (elem.hasChildNodes()) {
ssNodes = elem.getChildNodes();
// Vector to contain TransformerHandler for each stylesheet.
Vector vTHandler = new Vector(ssNodes.getLength());
// The child nodes of an extension element node are instances of
// ElemLiteralResult, which requires does not fully support the standard
// Node interface. Accordingly, some special handling is required (see below)
// to get attribute values.
for (int i = 0; i < ssNodes.getLength(); i++) {
ssNode = ssNodes.item(i);
if (ssNode.getNodeType() == Node.ELEMENT_NODE
&& ((Element) ssNode).getTagName().equals("stylesheet")
&& ssNode instanceof ElemLiteralResult) {
AVT avt = ((ElemLiteralResult) ssNode).getLiteralResultAttribute("href");
String href = avt.evaluate(xctxt, xt, elem);
String absURI = SystemIDResolver.getAbsoluteURI(href, sysId);
Templates tmpl = saxTFactory.newTemplates(new StreamSource(absURI));
TransformerHandler tHandler = saxTFactory.newTransformerHandler(tmpl);
Transformer trans = tHandler.getTransformer();
// AddTransformerHandler to vector
vTHandler.addElement(tHandler);
paramNodes = ssNode.getChildNodes();
for (int j = 0; j < paramNodes.getLength(); j++) {
paramNode = paramNodes.item(j);
if (paramNode.getNodeType() == Node.ELEMENT_NODE
&& ((Element) paramNode).getTagName().equals("param")
&& paramNode instanceof ElemLiteralResult) {
avt = ((ElemLiteralResult) paramNode).getLiteralResultAttribute("name");
String pName = avt.evaluate(xctxt, xt, elem);
avt = ((ElemLiteralResult) paramNode).getLiteralResultAttribute("value");
String pValue = avt.evaluate(xctxt, xt, elem);
trans.setParameter(pName, pValue);
}
}
}
}
usePipe(vTHandler, absSourceURL, target);
}
}