Transformer: DocumentFragment and SAX events

[Alessandro Vincelli]

Hi all,
I am trying to write a custom Transformer which should do the following:
ignore everything except <row> elements;
when an <row> element is encountered, generate a <tr> element, 
containing a <td> element for every child of the source <row> element;

example:
source:
...<anything>...
<row>
   <field1>A</field1>
   <field2>B</field2>
</row>
...</anything>...
should produce:
<tr>
   <td>A</td>
   <td>B</td>
</tr>

My approach is, when I find a <row> element, to use startRecording(), 
with endRecording() when the end of the <row> element is reached. Thus I 
get a DocumentFragment from which I can extract what I need.

The problem is that the resulting DocumentFragment gets populated with 
the nodes I need *only if I call super.startElement() for every 
element*. But, this way, I get in the result also elements I wish to 
suppress.

Example:
...<anything>...
<row>
   <field1>A</field1>
   <field2>B</field2>
</row>
...</anything>...
actually produces:
...<anything>...
<tr>
   <td>A</td>
   <td>B</td>
</tr>
...</anything>...
How can I overcome this? I am sure that I am doing something deeply 
wrong, as you can see from the attached source.

Thanks in advance,
Alessandro
package com.w4b.formProcessor;
import org.apache.cocoon.transformation.*;
import org.w3c.dom.DocumentFragment;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.Attributes;
import org.xml.sax.helpers.AttributesImpl;
import org.xml.sax.SAXException;
import org.apache.cocoon.transformation.AbstractTransformer;
import org.apache.cocoon.environment.SourceResolver;
import org.apache.cocoon.ProcessingException;
import org.apache.avalon.framework.parameters.Parameters;
import org.xml.sax.SAXException;
import java.util.Map;
public class ExcelOutputTransformer extends AbstractSAXTransformer
{
   boolean firstRow;
   AttributesImpl attrs = new AttributesImpl();
  
   public void startDocument() throws SAXException{
       firstRow = true;
       getLogger().debug("inizio documento...");
       super.startElement("","table","table",attrs);
   }
   public void endDocument() throws SAXException{
       getLogger().debug("fine documento.");
       super.endElement("","table","table");
   }
   public void startElement(String nsURI, String localName, String 
qualName, Attributes attr) throws SAXException{
      
       getLogger().debug(localName);
      
       if (!(localName.equals("row"))) {
           
super.contentHandler.startElement(nsURI,localName,qualName,attr);
           return;
       }
       getLogger().debug("inizio riga...");
       this.startRecording();
      
      
   }
   public void endElement(String nsURI, String localName, String 
qualName) throws SAXException{
      
       if (!(localName.equals("row"))) {
           super.contentHandler.endElement(nsURI,localName,qualName);
           return;
       }
              
       getLogger().debug("fine riga.");

      
       DocumentFragment df = this.endRecording();
      

       if (firstRow) {
           super.startElement("","tr","tr",attrs);
          
           Node n = df.getFirstChild();
           int i = 0;
          
           while (n!=null)  {
               i++;
              
               if (n!=null) {
                   super.startElement("","td","td",attrs);
                   String val = n.getNodeName();
                   super.characters(val.toCharArray(),0,val.length());
                   super.endElement("","td","td");
               } else {
                   getLogger().debug("nodo " + i + "nullo.");
               }
               n = n.getNextSibling();
           }
           super.endElement("","tr","tr");
           firstRow = false;
       }
      
       Node n = df.getFirstChild();
       int i = 0;
       super.startElement("","tr","tr",attrs);
       while (n!=null)  {
           i++;
           if (n.getFirstChild()!=null) {
               super.startElement("","td","td",attrs);
               String val = n.getFirstChild().getNodeValue();
               super.characters(val.toCharArray(),0,val.length());
               super.endElement("","td","td");

           }    else {
               getLogger().debug("nodo " + i + "nullo.");
           }
           n = n.getNextSibling();
       }
       super.endElement("","tr","tr");
      
   }
}



--
-------------------------------
Alessandro Vincelli 
W4B - web for business s.r.l.
Firenze 
via Pellicceria 10 - 50123
E-mail: [EMAIL PROTECTED]
tel: 055-2654270 

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