Created attachment 9637 [details]
A unified diff against HEAD.

Somewhat leery on this one--What are the use cases you're proposing for this?  
Attaching this type of debugging to a heavily-called function such as 
FOTreeBuilder.characters() could be a relatively high performance hit--so I 
want to make sure this passes a "cost-benefit" analysis.  As you see it, what 
are the benefits and what are the costs?

Is this just for testing use or you anticipate this while running in production 
as well?  The latter case, of course, would require more scrutiny.

Also, isn't it more common to store Locator information within the callee?  
I.e., have the FObj.toString() just return information about its inherent data 
to the callee, and let the latter append Locator info (or whatever else callee-
specific) to it--in those areas where we need to do debugging, troubleshooting, 
etc.

Thanks,
Glen

It is purely for debugging and tracing. 

The benefit is easier to read trace output when there is linenumbers, the cost 
is 3 to 4 additional virtual method calls for every fo element.

I can add a test so the methods are only called when running with -d option.

I don't know how the callee of toString() can add line numbers, the line number 
information of the fo elements are only available during the startElement() and 
characters() event.

OK, I misunderstood--I thought the line/column numbers referred to were of the 
callee (say, at point where it was referencing the particular FObj), not of the 
FO file itself.

This patch looks like a good idea, as I think it will allow us to give very 
solid error feedback for incorrect FO input.  At any rate, if it ever becomes a 
performance issue, it would be fairly simple to remove, or employ a non-
debugging flag as you mention.

Anyway, applied, thanks!

Glen

Please accept my apologies for breaking the build when running with a XMLFilter 
which doesn't gives locator information. A NPE will then occur.

The attached patch fixes the NPE.

Created attachment 9709 [details]
Unified patch against HEAD

Applied, thanks.

batch transition pre-FOP1.0 resolved+fixed bugs to closed+fixed