xsl 里增加



   function valueOf(context, elem) {

    return tools.valueOf(context, elem);

   }

代码里增加





 public String valueOf(XSLProcessorContext context, ElemExtensionCall elem) {

  String value = elem.getAttribute("select");

  String maxStr = elem.getAttribute("max");

  try {

   value = executeExpression(context, elem, value);

  } catch (TransformerException e) {

  }

  if (isNotBlank(maxStr)) {

   try {

    int max = Integer.parseInt(maxStr);

    value = shortStr(value, max);

   } finally {

   }

  }

  return value;

 }
 private String executeExpression(XSLProcessorContext context, ElemExtensionCall elem, String value)

   throws TransformerException {

  XPathContext xctxt = context.getTransformer().getXPathContext();

  XPath path = new XPath(value, elem, xctxt.getNamespaceContext(), XPath.SELECT);

  XObject data = path.execute(xctxt, context.getContextNode(), elem);

  if (data != null)

   value = data.xstr().toString();

  return value == null ? "" : value;

 }
























参考了下面的文档













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List:       xalan-j-users
Subject:    Re: Extension element with subelements
From:       John Gentilin <gentijo () eyecatching ! com>
Date:       2007-09-07 21:48:37
Message-ID: 46E1C735.2080504 () eyecatching ! com
[Download message RAW]
Oops... this might be what you are after instead...
executeChildTemplatesToXML or ToString or ToXMLString
may be what you are after..
/**
* A repository for common functions that can be used but the extension
* functions and extension elements.
*
*
* Title:       Base Functions
* Copyright:   Copyright (c) 2005
* Company:     Eye Catching Solutions Inc.
* @version     1.0
* @author      John Gentilin
*/
public class BaseFunctions
{
private static Category m_Log =
Category.getInstance("RapidXSL.Interface");
private static DocumentBuilderFactory  m_dfactory = null;
private static DocumentBuilder  m_docBuilder = null;
/**
* @param context
* @param elem
* @throws TransformerException
*/
protected void executeChildTemplates( XSLProcessorContext context,
ElemExtensionCall elem ) throws TransformerException
{
TransformerImpl transf = context.getTransformer();
transf.executeChildTemplates(elem,
context.getContextNode(),
context.getMode(), transf.getResultTreeHandler());
}
/**
* @param context
* @param elem
* @throws TransformerException
*/
protected Document executeChildTemplatesToXML(Document doc,
XSLProcessorContext context, ElemExtensionCall elem ) throws
XMLServerException
{
DOMBuilder builder = null;
TransformerImpl transformer = context.getTransformer();
try
{
builder = new DOMBuilder(doc);
transformer.executeChildTemplates(elem,
context.getContextNode(),
context.getMode(), builder);
}
catch (Exception e)
{
throw new XMLServerException("RXSL_IFACE", "XSL Interface Error -
" + e.getLocalizedMessage());
}
return doc;
}
/**
* @param context
* @param elem
* @throws TransformerException
*/
protected String executeChildTemplatesToString(XSLProcessorContext
context, ElemExtensionCall elem ) throws XMLServerException
{
TransformerImpl transformer = context.getTransformer();
try
{
TextSerializationHandler handler = new TextSerializationHandler();
transformer.executeChildTemplates(elem,
context.getContextNode(),
context.getMode(), handler);
return handler.toString();
}
catch (Exception e)
{
throw new XMLServerException("RXSL_IFACE", "XSL Interface Error -
" + e.getLocalizedMessage());
}
}
protected String executeChildTemplatestoXMLString(XSLProcessorContext
context, ElemExtensionCall elem)
throws TransformerException, SAXException
{
try
{
TransformerImpl transformer = context.getTransformer();
// This should be worked on so that the output format can be
// defined by a first child of the redirect element.
OutputProperties format = transformer.getOutputFormat();
Properties prop = format.getProperties();
format.setProperty("indent","no");
format.setProperty("{http://xml.apache.org/xalan}indent-amount","0");
ByteArrayOutputStream ostream = new ByteArrayOutputStream();
SerializationHandler serializer =
transformer.createSerializationHandler(
new StreamResult(ostream),
format);
serializer.startDocument();
transformer.executeChildTemplates(elem,
context.getContextNode(),
context.getMode(), serializer);
serializer.flushPending();
serializer.endDocument();
return ostream.toString("ISO-8859-1");
}
catch (UnsupportedEncodingException e)
{
m_Log.fatal("Error Encoding Bytes from XML - " +
e.getLocalizedMessage());
return new String();
}
}
/**
* Get the Node Value of a Stylesheet Element. This will be used to
collect
* the data value when populating a Control.....
*
* @return
*/
protected String getNodeValue( ElemExtensionCall elem )
{
Node child = elem.getFirstChild();
if (child != null)
{
return child.getNodeValue();
}
return null;
}
/**
* Resolve the Attribute Selection for the fixed attribute "select"
*
* @return
* @throws TransformerException
*/
protected String getStringValueFromSelectExpr(XSLProcessorContext
context, ElemExtensionCall elem  ) throws TransformerException
{
return getStringValueFromAttribute("select", context, elem);
}
/**
* Find the Attribute named "attrib" and convert that to an XPath statement
* that can be executed.
*
* Return null if the Attribute did not exist.
*
* @param attrib
* @return
* @throws TransformerException
*/
protected static XPath getAttributeExpr( String attrib,
XSLProcessorContext context, ElemExtensionCall elem ) throws
TransformerException
{
String expr =
elem.getAttribute (attrib,
context.getContextNode(),
context.getTransformer());
if(null != expr)
{
org.apache.xpath.XPathContext xctxt
= context.getTransformer().getXPathContext();
return new XPath(
expr,
elem,
xctxt.getNamespaceContext(), XPath.SELECT);
}
return null;
}
/**
*
* Get the value of an Attribute. It will first try to treat the
attribute as an XPath
* if that fails then just return the attribute value itself.
*
* @param attrName
* @param context
* @param elem
* @return
*/
protected String getStringValueFromAttribute( String attrName,
XSLProcessorContext context, ElemExtensionCall elem )
{
XPath path;
String value = null;
try
{
path = getAttributeExpr(attrName, context, elem);
if (path != null)
{
XObject data = executeXPath(path, context, elem);
if (data != null) value = data.xstr().toString();
}
}
catch (TransformerException e)
{
value = elem.getAttribute(attrName);
}
if (value == null) value = "";
return value;
}
/**
* A helper function to execute an XPath Object.
*
* @param path
* @return
* @throws TransformerException
*/
protected static XObject executeXPath( XPath path, XSLProcessorContext
context, ElemExtensionCall elem ) throws TransformerException
{
org.apache.xpath.XPathContext xctxt
= context.getTransformer().getXPathContext();
return path.execute(xctxt, context.getContextNode(), elem);
}
protected Document getEmptyDocument()
{
initDocFactory();
return m_docBuilder.newDocument();
}
protected static void initDocFactory()
{
if (m_dfactory != null) return;
try
{
m_dfactory = DocumentBuilderFactory.newInstance();
m_docBuilder = m_dfactory.newDocumentBuilder();
}
catch (Exception e)
{
m_Log.fatal("RapidXSL Interface, failure to init XML Subsystem - "
+ e.getLocalizedMessage());
}
}
}
Cynepnaxa wrote:
> Hi, everybody!
> I start to write simple extension element, but a problem occurs. I want to
> access extension element's subelements in java+xalan. My xsl contains
> following block of code:
> <my-ext:request>
> <body><xsl:value-of select="$body"/></body>
> <contentType>text/html</contentType>
> <metaData><![CDATA[<?xml version="1.0" encoding="utf-8"?>]]><metaData>
> <xsl:value-of select="$metaData"/>
> </metaData>
> </metaData>
> </my-ext:request>
> In extension element Java-method i have "XSLProcessorContext context" and
> "ElemExtensionCall elem". I can get contentType by calling for example
> "elem.getFirstChild().getNextSibling().getFirstChild().getTextContent()",
> but i want to access subelements by tag name(for example, by
> elem.getElementsByTagName("metadata"), or XPath). I have no idea how to
> access in java content of $body variable and xml - encapsulated $metaData.
> All google - examples shining no light. Is simple xslt - subelements access
> method exist? Big thanx for help.
> P.S. Sorry for my English. I hope you understand me.
>
>
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