Digester push(null)

[Joachim Fuchs <jo...@dai-labor.de>]

Hi,

I found this code in Tomcat's ContextConfig.java:

<code>
webDigester.clear();
webDigester.push(context);
webDigester.parse(is);
webDigester.push(null);
</code>

My question is what happens with the digester when pushing a null reference?
I expect a null pointer expetion to be thrown, so what is this good for?

I am not subscribed to the list, please CC me.

Joachim



Dipl. Inform. Joachim Fuchs
DAI-Labor - Technische Universität Berlin Sekretariat GOR 1-1, Franklinstraße 28/29, 10587 Berlin
Fon: +49 30 314 23383
joachim.fuchs@dai-labor.de
http://www.dai-labor.de  

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Re: Digester push(null)

[Simon Kitching <sk...@apache.org>]

Hi Joachim,

On Wed, 2006-06-28 at 14:37 +0200, Joachim Fuchs wrote:
> Hi,
> 
> I found this code in Tomcat's ContextConfig.java:
> 
> <code>
> webDigester.clear();
> webDigester.push(context);
> webDigester.parse(is);
> webDigester.push(null);
> </code>
> 
> My question is what happens with the digester when pushing a null reference?
> I expect a null pointer expetion to be thrown, so what is this good for?

There won't necessarily be a null pointer exception. That would only
happen if some rule is executed that tries to invoke a method on that
object on the stack.

However it does look rather odd. I can't think of a good reason for
pushing a null onto the stack, particularly *after* parsing is complete.

Can you provide the full package name for this class (and tomcat
version) so I can have a look at the tomcat code for myself?

Regards,

Simon



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