I took a look at your code and all seems fine. I am using basically
the same method
except I am caching transformers for speed and have not had a problem.
Is this on
Windows or Unix ?. I have heard of problems using the ODBC bridge code
under
Windows but have not been able to replicate it. Also have you tried
to use a stylesheet
that does not use any of the SQL code in your environment ??
I need to get something out
the door this week, but should be able to dive in and take a look by
the end of the week.
Regards
JohnG
PS, can you try the same code using the InstantDB as an example. I will
use InstantDB
as the test platform.
Jim Bugwadia wrote:
Hello,I've been trying to use Xalan's SQL extensions from a servlet. I'm
able to run everything successfully only once - immediately after
starting Tomcat, the servlet container.On any attempt to re-invoke the servlet I get an NullPointerException
exception. This happens either on doing a "refresh" or even after re-
starting the webapp. The exception is reported on the "transform"
method call.Here is the servlet code:
public class DBBrowse extends HttpServlet
{
public void init(ServletConfig config) throws ServletException
{
super.init(config);
}public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws IOException, ServletException
{response.setContentType("text/html; charset=UTF-8");
PrintWriter out = response.getWriter();try
{
TransformerFactory tFactory = TransformerFactory.newInstance();// Get the XML input document and the stylesheet.
Source xmlSource = new StreamSource(
new
URL("http://localhost:8080/dbbrowse/servlets/test.xml").openStream());Source xslSource = new StreamSource(
new
URL("http://localhost:8080/dbbrowse/servlets/test.xslt").openStream());// Generate the transformer.
Transformer transformer = tFactory.newTransformer(xslSource);// Perform the transformation, sending the output to the
response.
transformer.transform(xmlSource, new StreamResult(out));
}
catch (Exception e)
{
out.write(e.getMessage());
e.printStackTrace(out);
}out.close();
}
}And here is the stylesheet:
<?xml version="1.0"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
version="1.0"
xmlns:sql="org.apache.xalan.lib.sql.XConnection"
extension-element-prefixes="sql"><xsl:output method="html" indent="yes"/>
<xsl:param name="query" select="'SELECT * FROM SYS.TABLES'"/><xsl:template match="/">
<!-- 1. Make the connection -->
<xsl:variable name="products"
select="sql:new('com.timesten.jdbc.TimesTenDriver',
'jdbc:timesten:direct:JetCmeData')"/>
<HTML>
<HEAD>
</HEAD>
<BODY>
<TABLE border="1"><xsl:variable name="table" select='sql:query($products, $query)'/>
<TR>
<!-- Get column-label attribute from each column-header-->
<xsl:for-each select="$table/sql/metadata/column-header">
<TH><xsl:value-of select="@column-label"/></TH>
</xsl:for-each>
</TR><xsl:apply-templates select="$table/sql/row-set/row"/>
<xsl:text> </xsl:text></TABLE>
</BODY>
</HTML>
<!-- 3. Close the connection -->
<xsl:value-of select="sql:close($products)"/>
</xsl:template><xsl:template match="row">
<TR>
<xsl:apply-templates select="col"/>
</TR>
</xsl:template><xsl:template match="col">
<TD>
<!-- Here is the column data -->
<xsl:value-of select="text()"/>
</TD>
</xsl:template></xsl:stylesheet>
Any ideas on what could be the problem?
Btw, I can sucessfully invoke this styleheet multiple times from the
command line.Thanks,
Jim
PS: Here is the exception stack:
java.lang.NullPointerExceptionjavax.xml.transform.TransformerException:
java.lang.NullPointerException at
org.apache.xalan.transformer.TransformerImpl.transformNode(TransformerImpl.j
ava:1226) at
org.apache.xalan.transformer.TransformerImpl.transform(TransformerImpl.java:
638) at
org.apache.xalan.transformer.TransformerImpl.transform(TransformerImpl.java:
1088) at
org.apache.xalan.transformer.TransformerImpl.transform(TransformerImpl.java:
1066) at DBBrowse.doGet(DBBrowse.java:45) at
javax.servlet.http.HttpServlet.service(HttpServlet.java:740) at
javax.servlet.http.HttpServlet.service(HttpServlet.java:853) at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Application
FilterChain.java:247) at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterCh
ain.java:193) at
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.ja
va:243) at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
66) at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943) at
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.ja
va:201) at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
66) at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943) at
org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2344)
at
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164
) at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
66) at
org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.
java:170) at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
64) at
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:170
) at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
64) at
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:462) at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
64) at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943) at
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java
:163) at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
66) at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943) at
org.apache.catalina.connector.http.HttpProcessor.process(HttpProcessor.java:
1011) at
org.apache.catalina.connector.http.HttpProcessor.run(HttpProcessor.java:1106
) at java.lang.Thread.run(Unknown Source) ---------
java.lang.NullPointerException at
org.apache.xpath.axes.FilterExprWalker.getAxis(FilterExprWalker.java:301) at
org.apache.xpath.axes.WalkingIteratorSorted.canBeWalkedInNaturalDocOrder(Wal
kingIteratorSorted.java:128) at
org.apache.xpath.axes.WalkingIteratorSorted.setRoot(WalkingIteratorSorted.ja
va:172) at
org.apache.xpath.axes.LocPathIterator.asIterator(LocPathIterator.java:267)
at
org.apache.xalan.templates.ElemForEach.transformSelectedNodes(ElemForEach.ja
va:357) at
org.apache.xalan.templates.ElemForEach.execute(ElemForEach.java:287) at
org.apache.xalan.transformer.TransformerImpl.executeChildTemplates(Transform
erImpl.java:2182) at
org.apache.xalan.templates.ElemLiteralResult.execute(ElemLiteralResult.java:
678) at
org.apache.xalan.transformer.TransformerImpl.executeChildTemplates(Transform
erImpl.java:2182) at
org.apache.xalan.templates.ElemLiteralResult.execute(ElemLiteralResult.java:
678) at
org.apache.xalan.transformer.TransformerImpl.executeChildTemplates(Transform
erImpl.java:2182) at
org.apache.xalan.templates.ElemLiteralResult.execute(ElemLiteralResult.java:
678) at
org.apache.xalan.transformer.TransformerImpl.executeChildTemplates(Transform
erImpl.java:2182) at
org.apache.xalan.templates.ElemLiteralResult.execute(ElemLiteralResult.java:
678) at
org.apache.xalan.transformer.TransformerImpl.executeChildTemplates(Transform
erImpl.java:2182) at
org.apache.xalan.transformer.TransformerImpl.applyTemplateToNode(Transformer
Impl.java:2008) at
org.apache.xalan.transformer.TransformerImpl.transformNode(TransformerImpl.j
ava:1171) at
org.apache.xalan.transformer.TransformerImpl.transform(TransformerImpl.java:
638) at
org.apache.xalan.transformer.TransformerImpl.transform(TransformerImpl.java:
1088) at
org.apache.xalan.transformer.TransformerImpl.transform(TransformerImpl.java:
1066) at DBBrowse.doGet(DBBrowse.java:45) at
javax.servlet.http.HttpServlet.service(HttpServlet.java:740) at
javax.servlet.http.HttpServlet.service(HttpServlet.java:853) at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Application
FilterChain.java:247) at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterCh
ain.java:193) at
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.ja
va:243) at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
66) at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943) at
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.ja
va:201) at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
66) at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943) at
org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2344)
at
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164
) at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
66) at
org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.
java:170) at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
64) at
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:170
) at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
64) at
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:462) at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
64) at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943) at
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java
:163) at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
66) at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943) at
org.apache.catalina.connector.http.HttpProcessor.process(HttpProcessor.java:
1011) at
org.apache.catalina.connector.http.HttpProcessor.run(HttpProcessor.java:1106
) at java.lang.Thread.run(Unknown Source)
