Consecutive XSLT transformations

[Nathan Pride <np...@wavo.com>]

Hi All,
    A little history:
        This is a progression from how to include other xml documents in
a new document without using the ENTITY property. After upgrading to
Cocoon 1.6.1 and the new XSLT processors I now have some success BUT ...

    The problem:
        After the first XSLT transformation generating the new xml
document I don't know how to include the further processing
instructions.

    This is what I want

    XML --> [XSLT] --> XML --> [XSLT] --> HTML

    Here's how I'm trying to do it:.

File: page.xml

<?xml version="1.0"?>
<?xml-stylesheet href="stage1.xsl" type="text/xsl"?>
<?cocoon-process type="xslt"?>

<files>
 <external href="include1.xml"/>
 <external href="include2.xml"/>
</files>

File:    include1.xml

<?xml version="1.0"?>
<message>
 <text>Hello world type of text</text>
 Blah blah blah.
</message>

File:    include2.xml

<?xml version="1.0"?>
<message>
 <text>This is the other external file</text>
 Blah blah blah.
</message>

File:    stage1.xsl

<?xml version="1.0"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/XSL/Transform/1.0">
 <xsl:template match="external">
  <xsl:comment>Here are the contents of "external" URI <xsl:value-of
select="@href"/></xsl:comment>
  <other_file>
  <xsl:copy-of select="document(@href)"/>
  </other_file>
 </xsl:template>
 <xsl:template match="/">
  <document>
   <xsl:apply-templates/>
  </document>
 </xsl:template>
</xsl:stylesheet>

Which gives the result:

<?xml version="1.0" encoding="UTF-8"?>
 <document>
  <!--Here are the contents of "external" URI include1.xml-->
  <other_file>
   <message>
    <text>Hello world type of text</text>
    Blah blah blah.
   </message>
  </other_file>
  <!--Here are the contents of "external" URI include2.xml-->
  <other_file>
   <message>
    <text>This is the other external file</text>
    Blah blah blah.
   </message>
 </other_file>
</document>

Great, however I would like to transform the result by using the
following:


File: stage2.xsl

<?xml version="1.0"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/XSL/Transform/1.0">
 <xsl:template match="/">
  <xsl:processing-instruction
name="cocoon-format">type="text/html"</xsl:processing-instruction>
  <html>
   <head>
    <title>Consecutive XSLT processing example.</title>
   </head>
   <body>
    <xsl:apply-templates/>
   </body>
  </html>
 </xsl:template>
 <xsl:template match="message">
  <table bgcolor="yellow" border="1">
   <tr>
    <td>
     <xsl:apply-templates/>
    </td>
   </tr>
  </table>
  <p/>
 </xsl:template>
 <xsl:template match="text">
      <font color="blue"><xsl:apply-templates/></font>
 </xsl:template>
</xsl:stylesheet>

Now to do this I believe I need the following lines to be generated
within the first result:

<?xml version="1.0" encoding="UTF-8"?>                <!-- already there
-->
<?xml-stylesheet href="stage2.xsl" type="text/xsl"?>  <!-- new -->
<?cocoon-process type="xslt"?>                        <!-- new -->
<document>
.... etc.

to do that I thought the following lines would be required in stage1.xsl

<?xml version="1.0"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/XSL/Transform/1.0">
 <xsl:template match="external">
  <xsl:comment>Here are the contents of "external" URI <xsl:value-of
select="@href"/></xsl:comment>
  <other_file>
  <xsl:copy-of select="document(@href)"/>
  </other_file>
 </xsl:template>
 <xsl:template match="/">
  <!-- ***** New code **** -->
  <xsl:processing-instruction type="xml-stylesheet">
   href="stage2.xsl" type="text/xsl"
  </xsl:processing-instruction>
  <xsl:processing-instruction type="cocoon-process">
   type="xslt"
  </xsl:processing-instruction>
  <!-- ***** /New code **** -->
  <document>
   <xsl:apply-templates/>
  </document>
 </xsl:template>
</xsl:stylesheet>

However when I try to do this I get the following error from Cocoon
"Error found handling the request" with the following stack trace:

 at org.apache.xalan.xslt.XSLTEngineImpl.error(XSLTEngineImpl.java:1487)

 at org.apache.xalan.xslt.XSLTEngineImpl.error(XSLTEngineImpl.java:1396)

 at org.apache.xalan.xslt.ElemPI.(ElemPI.java, Compiled Code)
 at
org.apache.xalan.xslt.StylesheetHandler.startElement(StylesheetHandler.java,
Compiled Code)
 at org.apache.xalan.xpath.xml.TreeWalker.startNode(TreeWalker.java,
Compiled Code)
 at org.apache.xalan.xpath.xml.TreeWalker.traverse(TreeWalker.java,
Compiled Code)
 at
org.apache.xalan.xslt.XSLTEngineImpl.processStylesheet(XSLTEngineImpl.java:658)

 at org.apache.xalan.xslt.XSLTEngineImpl.process(XSLTEngineImpl.java,
Compiled Code)
 at
org.apache.cocoon.transformer.XalanTransformer.transform(XalanTransformer.java:94)

 at
org.apache.cocoon.processor.xslt.XSLTProcessor.process(XSLTProcessor.java:103)

 at org.apache.cocoon.Engine.handle(Engine.java, Compiled Code)
 at org.apache.cocoon.Cocoon.service(Cocoon.java:145)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:588)
 at
org.apache.jserv.JServConnection.processRequest(JServConnection.java:314)

 at org.apache.jserv.JServConnection.run(JServConnection.java:188)
 at java.lang.Thread.run(Thread.java:479)

Just for the record;
Running on NT
Apache 1.3.9
Cocoon 1.6.1
Xerces  0.19.2
Xalan  1.0.1

Thanks in advance

Nathan