I think I've diagnosed the problem:
1) Transform#1 creates an XRTreeFrag. This has a reference to a DTM, that
in turn is registered with a DTMManager. The DTM will need to be deleted
from the DTMManager when the XRTreeFrag is deleted. The XRTreeFrag also
contains a reference to the XPathContext.
2) Transform#1 completes. The XPathContext is reset... namely the a bunch
of structures are reset or rebuilt, including DTMManagerDefault#m_dtms.
BUT, the XRTreeFrags are still hanging around, waiting to unregister
themselves.
3) Transform#2 starts humming along. It builds a XRTreeFrag and installs
that RTF DTM into DTMManagerDefault#m_dtms[2].
4) The finalizer thread wakes and decides to delete some of those old
XRTreeFrags from Transform#1.
5) The XRTreeFrag#finalize() method references through the XPathContext,
and deletes what it thinks is it's DTM from DTMManagerDefault#m_dtms[2]
(via getDTMIdentity(dtm)).
6) Transform#2 tries to reference DTMManagerDefault#m_dtms[2], finds it is
null, and chaos results.
Working on a (safe and reasonable) solution.
-scott
"Frank E. Weiss"
<[EMAIL PROTECTED]> To:
cc: [EMAIL PROTECTED],
(bcc: Scott Boag/Cambridge/IBM)
04/02/2002 12:28 Subject: Re: Stylesheet Reuse
NullPointerException
PM
Scott, thanks for the update.
> I can reproduce it from the DOS command prompt, but
> not in my debugger.
Ouch. Maybe I'll try runiing it on Linux and see if it reproduces. Sounds
like as, Joseph said, a timing problem.
> Also, your tests are not reusing the transformer... you create a new
transformer every time...
> so it's got nothing to do with that either.
Hmm. Really? The transformer is created outside the loop
Transformer transformer = tfactory.newTransformer(new StreamSource(xslID));
and inside the loop the call
transformer.transform( new StreamSource(sourceID),
new StreamResult("reuse00"));
I thought that's the way the example shows transformer reuse.
