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Posted to fop-users@xmlgraphics.apache.org by Steve Roy <s_...@hotmail.com> on 2006/01/26 15:03:35 UTC
NullPointerExceptions
Hello,
I find I am only presented with NullPointerExceptions from FOP when there is
some type of problem with the rendering. I haven't noticed any info on
turning on verbose logging or something of the sort. Any suggestions on
troubleshooting problems with the source xml or xslt?
As an example, here is the current stack trace I am receiving:
javax.xml.transform.TransformerException: java.lang.NullPointerException
at
org.apache.xalan.transformer.TransformerImpl.transformNode(TransformerImpl.java:1276)
at
org.apache.xalan.transformer.TransformerImpl.transform(TransformerImpl.java:668)
at
org.apache.xalan.transformer.TransformerImpl.transform(TransformerImpl.java:1129)
at
org.apache.xalan.transformer.TransformerImpl.transform(TransformerImpl.java:1107)
at com.myco.myapp.xslfo.FOEngineFacadeFOP.transform(Unknown Source)
at com.myco.myapp.xslfo.FOTransformer.transform(Unknown Source)
at
com.myco.myapp.businessservice.ejb.DocumentGenerationServiceBeanEJB.getPDFForItem(Unknown
Source)
at
com.myco.myapp.businessservice.docgen.DocumentGenerationService.getPDFForItem(Unknown
Source)
Caused by: java.lang.NullPointerException
at org.apache.fop.render.pdf.PDFRenderer.stopRenderer(PDFRenderer.java:266)
at
org.apache.fop.area.RenderPagesModel.endDocument(RenderPagesModel.java:228)
at org.apache.fop.area.AreaTreeHandler.endDocument(AreaTreeHandler.java:326)
at org.apache.fop.fo.FOTreeBuilder.endDocument(FOTreeBuilder.java:246)
at
org.apache.xalan.transformer.ResultTreeHandler.endDocument(ResultTreeHandler.java:192)
at
org.apache.xalan.transformer.TransformerImpl.transformNode(TransformerImpl.java:1224)
- steve
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Re: NullPointerExceptions
Posted by Steve Roy <s_...@hotmail.com>.
ok - good info.
Thanks Jeremias.
- steve
From: Jeremias Maerki <de...@jeremias-maerki.ch>
Reply-To: fop-users@xmlgraphics.apache.org
To: fop-users@xmlgraphics.apache.org
Subject: Re: NullPointerExceptions
Date: Thu, 26 Jan 2006 23:05:06 +0100
The Fop instance (unlike the Driver class in 0.20.5) is not supposed to
be reused. We will later add an environment class which will encapsulate
all the reusable parts of Fop as part of future optimization work. I
guess we should add a safe-guard that "one-use" components like the
FOTreeBuilder instance prepared by the Fop class are not used more than
once to avoid side-effects like you experienced. I'll see to that
tomorrow.
See also: http://xmlgraphics.apache.org/fop/0.91/embedding.html#object-reuse
On 26.01.2006 22:39:27 Steve Roy wrote:
> Hi,
>
> Thanks for the help Jeremias.
>
> Command line worked fine. The problems seems to occur when running
embedded
> when the same FOP instance is called repeatedly for the multiple pdf
> generations. Is there some kind of reset method that needs to be called
on
> FOP?
>
> We debugged and pdfDoc was null in stopRenderer on the subsequent call:
>
> public void stopRenderer() throws IOException {
> pdfDoc.getResources().addFonts(pdfDoc, fontInfo);
> pdfDoc.outputTrailer(ostream);
>
> this.pdfDoc = null;
> ostream = null;
>
> pages = null;
>
> pageReferences.clear();
> pvReferences.clear();
> pdfResources = null;
> currentStream = null;
> currentContext = null;
> currentPage = null;
> currentState = null;
> currentFontName = "";
> }
>
>
> - steve
>
>
>
> From: Jeremias Maerki <de...@jeremias-maerki.ch>
> Reply-To: fop-users@xmlgraphics.apache.org
> To: fop-users@xmlgraphics.apache.org
> Subject: Re: NullPointerExceptions
> Date: Thu, 26 Jan 2006 15:19:21 +0100
>
> Information about configuring the logging backend can be found in [1].
> Mostly we defer to the Jakarta Commons Logging documentation for that.
> If you work with JDK 1.4 and later JCL logs to the Java Logging API by
> default.
>
> [1] http://xmlgraphics.apache.org/fop/0.91/embedding.html#basic-logging
>
> In your case, however, I don't think that a lot of logging will help a
> lot. That's a pretty unusual exception. The NPE happens in
> PDFRenderer.stopRenderer() on the line where the font resources are
> added to the PDF. It looks like out of some weird reason the pdfDoc
> variable is null again. I can only imagine this happening if the SAX
> endDocument() method is called twice by the Transformer. I know that
> certain Xalan versions don't always issue the right SAX events. Maybe
> you hit such a problem.
>
> Here's what I would do: Run your current document from the FOP
> command-line and check if the same problem occurs. Setup FOP so you can
> debug FOP and set a breakpoint in PDFRenderer.stopRenderer() and check
> how many times this method is called. For a single rendering run, this
> method must be called exactly once, not more, not less.
>
> If my suspicion is right, try upgrading to the latest Xalan-J release.
> If that doesn't help, get back here.
>
> Good luck!
>
> On 26.01.2006 15:03:35 Steve Roy wrote:
> > Hello,
> >
> > I find I am only presented with NullPointerExceptions from FOP when
there
> is
> > some type of problem with the rendering. I haven't noticed any info
on
> > turning on verbose logging or something of the sort. Any suggestions
on
> > troubleshooting problems with the source xml or xslt?
> >
> > As an example, here is the current stack trace I am receiving:
> >
> > javax.xml.transform.TransformerException:
java.lang.NullPointerException
> > at
> >
>
org.apache.xalan.transformer.TransformerImpl.transformNode(TransformerImpl.java:1276)
> > at
> >
>
org.apache.xalan.transformer.TransformerImpl.transform(TransformerImpl.java:668)
> > at
> >
>
org.apache.xalan.transformer.TransformerImpl.transform(TransformerImpl.java:1129)
> > at
> >
>
org.apache.xalan.transformer.TransformerImpl.transform(TransformerImpl.java:1107)
> > at com.myco.myapp.xslfo.FOEngineFacadeFOP.transform(Unknown Source)
> > at com.myco.myapp.xslfo.FOTransformer.transform(Unknown Source)
> > at
> >
>
com.myco.myapp.businessservice.ejb.DocumentGenerationServiceBeanEJB.getPDFForItem(Unknown
> > Source)
> > at
> >
>
com.myco.myapp.businessservice.docgen.DocumentGenerationService.getPDFForItem(Unknown
> > Source)
> > Caused by: java.lang.NullPointerException
> > at
> org.apache.fop.render.pdf.PDFRenderer.stopRenderer(PDFRenderer.java:266)
> > at
> >
>
org.apache.fop.area.RenderPagesModel.endDocument(RenderPagesModel.java:228)
> > at
> org.apache.fop.area.AreaTreeHandler.endDocument(AreaTreeHandler.java:326)
> > at org.apache.fop.fo.FOTreeBuilder.endDocument(FOTreeBuilder.java:246)
> > at
> >
>
org.apache.xalan.transformer.ResultTreeHandler.endDocument(ResultTreeHandler.java:192)
> > at
> >
>
org.apache.xalan.transformer.TransformerImpl.transformNode(TransformerImpl.java:1224)
> >
> > - steve
>
>
> Jeremias Maerki
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: fop-users-unsubscribe@xmlgraphics.apache.org
> For additional commands, e-mail: fop-users-help@xmlgraphics.apache.org
>
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: fop-users-unsubscribe@xmlgraphics.apache.org
> For additional commands, e-mail: fop-users-help@xmlgraphics.apache.org
Jeremias Maerki
---------------------------------------------------------------------
To unsubscribe, e-mail: fop-users-unsubscribe@xmlgraphics.apache.org
For additional commands, e-mail: fop-users-help@xmlgraphics.apache.org
---------------------------------------------------------------------
To unsubscribe, e-mail: fop-users-unsubscribe@xmlgraphics.apache.org
For additional commands, e-mail: fop-users-help@xmlgraphics.apache.org
Re: NullPointerExceptions
Posted by Jeremias Maerki <de...@jeremias-maerki.ch>.
The Fop instance (unlike the Driver class in 0.20.5) is not supposed to
be reused. We will later add an environment class which will encapsulate
all the reusable parts of Fop as part of future optimization work. I
guess we should add a safe-guard that "one-use" components like the
FOTreeBuilder instance prepared by the Fop class are not used more than
once to avoid side-effects like you experienced. I'll see to that
tomorrow.
See also: http://xmlgraphics.apache.org/fop/0.91/embedding.html#object-reuse
On 26.01.2006 22:39:27 Steve Roy wrote:
> Hi,
>
> Thanks for the help Jeremias.
>
> Command line worked fine. The problems seems to occur when running embedded
> when the same FOP instance is called repeatedly for the multiple pdf
> generations. Is there some kind of reset method that needs to be called on
> FOP?
>
> We debugged and pdfDoc was null in stopRenderer on the subsequent call:
>
> public void stopRenderer() throws IOException {
> pdfDoc.getResources().addFonts(pdfDoc, fontInfo);
> pdfDoc.outputTrailer(ostream);
>
> this.pdfDoc = null;
> ostream = null;
>
> pages = null;
>
> pageReferences.clear();
> pvReferences.clear();
> pdfResources = null;
> currentStream = null;
> currentContext = null;
> currentPage = null;
> currentState = null;
> currentFontName = "";
> }
>
>
> - steve
>
>
>
> From: Jeremias Maerki <de...@jeremias-maerki.ch>
> Reply-To: fop-users@xmlgraphics.apache.org
> To: fop-users@xmlgraphics.apache.org
> Subject: Re: NullPointerExceptions
> Date: Thu, 26 Jan 2006 15:19:21 +0100
>
> Information about configuring the logging backend can be found in [1].
> Mostly we defer to the Jakarta Commons Logging documentation for that.
> If you work with JDK 1.4 and later JCL logs to the Java Logging API by
> default.
>
> [1] http://xmlgraphics.apache.org/fop/0.91/embedding.html#basic-logging
>
> In your case, however, I don't think that a lot of logging will help a
> lot. That's a pretty unusual exception. The NPE happens in
> PDFRenderer.stopRenderer() on the line where the font resources are
> added to the PDF. It looks like out of some weird reason the pdfDoc
> variable is null again. I can only imagine this happening if the SAX
> endDocument() method is called twice by the Transformer. I know that
> certain Xalan versions don't always issue the right SAX events. Maybe
> you hit such a problem.
>
> Here's what I would do: Run your current document from the FOP
> command-line and check if the same problem occurs. Setup FOP so you can
> debug FOP and set a breakpoint in PDFRenderer.stopRenderer() and check
> how many times this method is called. For a single rendering run, this
> method must be called exactly once, not more, not less.
>
> If my suspicion is right, try upgrading to the latest Xalan-J release.
> If that doesn't help, get back here.
>
> Good luck!
>
> On 26.01.2006 15:03:35 Steve Roy wrote:
> > Hello,
> >
> > I find I am only presented with NullPointerExceptions from FOP when there
> is
> > some type of problem with the rendering. I haven't noticed any info on
> > turning on verbose logging or something of the sort. Any suggestions on
> > troubleshooting problems with the source xml or xslt?
> >
> > As an example, here is the current stack trace I am receiving:
> >
> > javax.xml.transform.TransformerException: java.lang.NullPointerException
> > at
> >
> org.apache.xalan.transformer.TransformerImpl.transformNode(TransformerImpl.java:1276)
> > at
> >
> org.apache.xalan.transformer.TransformerImpl.transform(TransformerImpl.java:668)
> > at
> >
> org.apache.xalan.transformer.TransformerImpl.transform(TransformerImpl.java:1129)
> > at
> >
> org.apache.xalan.transformer.TransformerImpl.transform(TransformerImpl.java:1107)
> > at com.myco.myapp.xslfo.FOEngineFacadeFOP.transform(Unknown Source)
> > at com.myco.myapp.xslfo.FOTransformer.transform(Unknown Source)
> > at
> >
> com.myco.myapp.businessservice.ejb.DocumentGenerationServiceBeanEJB.getPDFForItem(Unknown
> > Source)
> > at
> >
> com.myco.myapp.businessservice.docgen.DocumentGenerationService.getPDFForItem(Unknown
> > Source)
> > Caused by: java.lang.NullPointerException
> > at
> org.apache.fop.render.pdf.PDFRenderer.stopRenderer(PDFRenderer.java:266)
> > at
> >
> org.apache.fop.area.RenderPagesModel.endDocument(RenderPagesModel.java:228)
> > at
> org.apache.fop.area.AreaTreeHandler.endDocument(AreaTreeHandler.java:326)
> > at org.apache.fop.fo.FOTreeBuilder.endDocument(FOTreeBuilder.java:246)
> > at
> >
> org.apache.xalan.transformer.ResultTreeHandler.endDocument(ResultTreeHandler.java:192)
> > at
> >
> org.apache.xalan.transformer.TransformerImpl.transformNode(TransformerImpl.java:1224)
> >
> > - steve
>
>
> Jeremias Maerki
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: fop-users-unsubscribe@xmlgraphics.apache.org
> For additional commands, e-mail: fop-users-help@xmlgraphics.apache.org
>
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: fop-users-unsubscribe@xmlgraphics.apache.org
> For additional commands, e-mail: fop-users-help@xmlgraphics.apache.org
Jeremias Maerki
---------------------------------------------------------------------
To unsubscribe, e-mail: fop-users-unsubscribe@xmlgraphics.apache.org
For additional commands, e-mail: fop-users-help@xmlgraphics.apache.org
Re: NullPointerExceptions
Posted by Steve Roy <s_...@hotmail.com>.
Hi,
Thanks for the help Jeremias.
Command line worked fine. The problems seems to occur when running embedded
when the same FOP instance is called repeatedly for the multiple pdf
generations. Is there some kind of reset method that needs to be called on
FOP?
We debugged and pdfDoc was null in stopRenderer on the subsequent call:
public void stopRenderer() throws IOException {
pdfDoc.getResources().addFonts(pdfDoc, fontInfo);
pdfDoc.outputTrailer(ostream);
this.pdfDoc = null;
ostream = null;
pages = null;
pageReferences.clear();
pvReferences.clear();
pdfResources = null;
currentStream = null;
currentContext = null;
currentPage = null;
currentState = null;
currentFontName = "";
}
- steve
From: Jeremias Maerki <de...@jeremias-maerki.ch>
Reply-To: fop-users@xmlgraphics.apache.org
To: fop-users@xmlgraphics.apache.org
Subject: Re: NullPointerExceptions
Date: Thu, 26 Jan 2006 15:19:21 +0100
Information about configuring the logging backend can be found in [1].
Mostly we defer to the Jakarta Commons Logging documentation for that.
If you work with JDK 1.4 and later JCL logs to the Java Logging API by
default.
[1] http://xmlgraphics.apache.org/fop/0.91/embedding.html#basic-logging
In your case, however, I don't think that a lot of logging will help a
lot. That's a pretty unusual exception. The NPE happens in
PDFRenderer.stopRenderer() on the line where the font resources are
added to the PDF. It looks like out of some weird reason the pdfDoc
variable is null again. I can only imagine this happening if the SAX
endDocument() method is called twice by the Transformer. I know that
certain Xalan versions don't always issue the right SAX events. Maybe
you hit such a problem.
Here's what I would do: Run your current document from the FOP
command-line and check if the same problem occurs. Setup FOP so you can
debug FOP and set a breakpoint in PDFRenderer.stopRenderer() and check
how many times this method is called. For a single rendering run, this
method must be called exactly once, not more, not less.
If my suspicion is right, try upgrading to the latest Xalan-J release.
If that doesn't help, get back here.
Good luck!
On 26.01.2006 15:03:35 Steve Roy wrote:
> Hello,
>
> I find I am only presented with NullPointerExceptions from FOP when there
is
> some type of problem with the rendering. I haven't noticed any info on
> turning on verbose logging or something of the sort. Any suggestions on
> troubleshooting problems with the source xml or xslt?
>
> As an example, here is the current stack trace I am receiving:
>
> javax.xml.transform.TransformerException: java.lang.NullPointerException
> at
>
org.apache.xalan.transformer.TransformerImpl.transformNode(TransformerImpl.java:1276)
> at
>
org.apache.xalan.transformer.TransformerImpl.transform(TransformerImpl.java:668)
> at
>
org.apache.xalan.transformer.TransformerImpl.transform(TransformerImpl.java:1129)
> at
>
org.apache.xalan.transformer.TransformerImpl.transform(TransformerImpl.java:1107)
> at com.myco.myapp.xslfo.FOEngineFacadeFOP.transform(Unknown Source)
> at com.myco.myapp.xslfo.FOTransformer.transform(Unknown Source)
> at
>
com.myco.myapp.businessservice.ejb.DocumentGenerationServiceBeanEJB.getPDFForItem(Unknown
> Source)
> at
>
com.myco.myapp.businessservice.docgen.DocumentGenerationService.getPDFForItem(Unknown
> Source)
> Caused by: java.lang.NullPointerException
> at
org.apache.fop.render.pdf.PDFRenderer.stopRenderer(PDFRenderer.java:266)
> at
>
org.apache.fop.area.RenderPagesModel.endDocument(RenderPagesModel.java:228)
> at
org.apache.fop.area.AreaTreeHandler.endDocument(AreaTreeHandler.java:326)
> at org.apache.fop.fo.FOTreeBuilder.endDocument(FOTreeBuilder.java:246)
> at
>
org.apache.xalan.transformer.ResultTreeHandler.endDocument(ResultTreeHandler.java:192)
> at
>
org.apache.xalan.transformer.TransformerImpl.transformNode(TransformerImpl.java:1224)
>
> - steve
Jeremias Maerki
---------------------------------------------------------------------
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For additional commands, e-mail: fop-users-help@xmlgraphics.apache.org
---------------------------------------------------------------------
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Re: NullPointerExceptions
Posted by Jeremias Maerki <de...@jeremias-maerki.ch>.
Information about configuring the logging backend can be found in [1].
Mostly we defer to the Jakarta Commons Logging documentation for that.
If you work with JDK 1.4 and later JCL logs to the Java Logging API by
default.
[1] http://xmlgraphics.apache.org/fop/0.91/embedding.html#basic-logging
In your case, however, I don't think that a lot of logging will help a
lot. That's a pretty unusual exception. The NPE happens in
PDFRenderer.stopRenderer() on the line where the font resources are
added to the PDF. It looks like out of some weird reason the pdfDoc
variable is null again. I can only imagine this happening if the SAX
endDocument() method is called twice by the Transformer. I know that
certain Xalan versions don't always issue the right SAX events. Maybe
you hit such a problem.
Here's what I would do: Run your current document from the FOP
command-line and check if the same problem occurs. Setup FOP so you can
debug FOP and set a breakpoint in PDFRenderer.stopRenderer() and check
how many times this method is called. For a single rendering run, this
method must be called exactly once, not more, not less.
If my suspicion is right, try upgrading to the latest Xalan-J release.
If that doesn't help, get back here.
Good luck!
On 26.01.2006 15:03:35 Steve Roy wrote:
> Hello,
>
> I find I am only presented with NullPointerExceptions from FOP when there is
> some type of problem with the rendering. I haven't noticed any info on
> turning on verbose logging or something of the sort. Any suggestions on
> troubleshooting problems with the source xml or xslt?
>
> As an example, here is the current stack trace I am receiving:
>
> javax.xml.transform.TransformerException: java.lang.NullPointerException
> at
> org.apache.xalan.transformer.TransformerImpl.transformNode(TransformerImpl.java:1276)
> at
> org.apache.xalan.transformer.TransformerImpl.transform(TransformerImpl.java:668)
> at
> org.apache.xalan.transformer.TransformerImpl.transform(TransformerImpl.java:1129)
> at
> org.apache.xalan.transformer.TransformerImpl.transform(TransformerImpl.java:1107)
> at com.myco.myapp.xslfo.FOEngineFacadeFOP.transform(Unknown Source)
> at com.myco.myapp.xslfo.FOTransformer.transform(Unknown Source)
> at
> com.myco.myapp.businessservice.ejb.DocumentGenerationServiceBeanEJB.getPDFForItem(Unknown
> Source)
> at
> com.myco.myapp.businessservice.docgen.DocumentGenerationService.getPDFForItem(Unknown
> Source)
> Caused by: java.lang.NullPointerException
> at org.apache.fop.render.pdf.PDFRenderer.stopRenderer(PDFRenderer.java:266)
> at
> org.apache.fop.area.RenderPagesModel.endDocument(RenderPagesModel.java:228)
> at org.apache.fop.area.AreaTreeHandler.endDocument(AreaTreeHandler.java:326)
> at org.apache.fop.fo.FOTreeBuilder.endDocument(FOTreeBuilder.java:246)
> at
> org.apache.xalan.transformer.ResultTreeHandler.endDocument(ResultTreeHandler.java:192)
> at
> org.apache.xalan.transformer.TransformerImpl.transformNode(TransformerImpl.java:1224)
>
> - steve
Jeremias Maerki
---------------------------------------------------------------------
To unsubscribe, e-mail: fop-users-unsubscribe@xmlgraphics.apache.org
For additional commands, e-mail: fop-users-help@xmlgraphics.apache.org