https://issues.apache.org/bugzilla/show_bug.cgi?id=46486





--- Comment #9 from Andreas L. Delmelle <adelme...@apache.org>  2009-04-06 
11:05:42 PST ---

Status update:
Been busy attempting to complete the deferral mechanism. 
By itself, not very complicated changes (only 2 affected classes), but all
sorts of other issues keep arising... There is some progress, but not as much
as I'd hoped.
It seems to require some more invasive refactoring than I had in mind.

One interesting scenario that keeps boggling me is:
-> a regular block with span="none", taking up a bit more than a page, followed
by
-> a block with span="all" that, by itself, would take up exactly one page

The first block will be split, and leaves a deferred part, to which
column-balancing should be applied.
I at least got that working for the minimized sample file. To my dismay, then
noticed the original one (with two span changes on the last page) exhibits some
other weirdness.

Apart from that, my current approach does not solve the case described above. 
Since I do not yet process the trailing sequence until the preceding deferred
part is processed, it seems I can no longer accurately determine the last page
condition. hasMoreContent() has been refactored here, to take into account the
deferred part, so the last page condition would never be reached (it will only
return false if the breaker is currently processing the last part, so as long
as there's still a deferred part...)
Using childFLM.isFinished() offers relief to trigger last page handling, but
then this still requires at least running the trailing sequence through the
algorithm /first/, to see if there is more than one page-break in combination
with the deferred part. If not, only then can we safely add the deferred areas
to what we know will be the last page.

If so, then we will have processed the deferred part three times. Once with the
initial run, where the sequence is deferred. A second time to check whether it
would cause a page-break in the following sequence, then a third time to
actually add the areas.

Writing this, it becomes apparent that I'll probably have to go in the
direction of instantiating the BreakingAlgorithm, but deferring it, rather than
deferring the original block list...

<TBC>

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