How to extract an element value from a String of HTML

Question

I have a web service that returns a fragment of HTML that contains a number in a table. The return parameter type is a string. I need to get this number and use it in a BPEL while loop, as the condition for the loop (while the number > 0).
I have tried using the function bpws:getVariableData() but the BPEL PM faults and says: XPath expression failed to execute. Error while processing xpath expression. I think this is because I am trying to apply an XPath expression over a String variable.
The return value from my web service looks like this:
<whileConditionResultSet>
<part xmlns:xsi="http://www.w3.org/1999/XMLSchema-instance" name="response">
<ns1:string_Response xmlns:ns1="http://systinet.com/xsd/SchemaTypes/"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="d:string">
     <p>SQL Query: select count(*) from delta_manages</p>
     <p><table border='1'>
          <tr> <th bgcolor='#C0C0C0'>COUNT(*)</th></tr>
          <tr> <td>28</td></tr>
          </table>
     </p></ns1:string_Response>
</part>
</whileConditionResultSet>
How do I get the value from the HTML table into a BPEL variable?

Answer 1

the doSqlService() which executes an arbitrary SQL statement, returns a string of HTML like this:
<doSqlServiceResponse>
<part xmlns:xsi="http://www.w3.org/1999/XMLSchema-instance" name="response">
<ns1:string_Response xmlns:ns1="http://systinet.com/xsd/SchemaTypes/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="d:string"><p>SQL Query: select count(*) from delta_manages</p> <p><table border='1'> <tr> <th bgcolor='#C0C0C0'>COUNT(*)</th></tr> <tr> <td>14</td></tr> </table></p></ns1:string_Response>
</part>
I then copy the result to the whileResultString variable
<variable name="whileResultString" type="xsd:string"/>
<copy>
                                   <from variable="doSqlServiceResponse" part="response" query="/ns1:string_Response">
                                   </from>
                                   <to variable="whileResultString"/>
                              </copy>
I realise too, a root element will be needed. This is not a mission critical problem as we could change the web service at the other end. It was originally designed for a client to display the results rather than use them within a business process. Anyway, I'm just interested to know if I can create a node from this string data in BPEL.
Ross.