[FOP-1120] [patch] force-page-count property implementation

• Type: Improvement
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 2.5
• Component/s: layout/unqualified
• Environment: Operating System: other; Platform: Other
• External issue ID: 38087
• Assignee: fop-dev
• Reporter: gerhard oettl
• Created: 01/Jan/06 13:42
• Updated: 07/Jan/06 12:34
• Resolved: 01/Apr/12 06:39

Description

This patch (re)implements the force-page-count property.

I tried to implement it with as little changes to the
code as possible. Therefore some design issues and questions
remain - see later.

Description:
The force-page-count property is handled by adding a method
to the PageSequenceLayoutManger, because there are is a
method that has all informations (static content, pagenumber,
...) about creating a new page (makeNewPage).
The main problem was that the force-page-count property needs
the initial-page-number of the next page-sequence which does
not exist at this time.
I solved this by preserving the current PageSequenceLayoutManger
after the end of the page-sequence. I used the Root object
for this because the last pagenumber of the sequence and other
informations are also handed over this object from one
page-sequence to the other. At the beginning of the following
page-sequence the (stored) previous PageSequenceLayoutManger
is called with the now current PageSequence object to finish
this work.

Changes to Root.java:

• insert the variable previousPageSeqLM to store a
  PageSequenceLayoutManger for later use
  (and import the necessary class definition).

Changes to PageSequenceLayoutManger.java:

• split off the last part of activateLayout into a separate
  method (finishLeayout) because i need the same functionality
  after the force-page-count handling.
• preserve the current PageSequenceLayoutManger object to the
  Root object at the end of the finishLayout method.
• implement the force-page-count propterty in the
  checkForcePageCount method. This method needs the next
  PageSequence object as parameter. To get the initial-page-number
  property of this next page-sequence i copied the code from
  PageSequence.initPageNumber.

Changes to PageSequence.java:

• call the checkForcePageCount method of the preserved previous
  PageSequenceLayoutManger inside the startOfNode method
  immediately before initPageNumber so that this method is
  waware of possibly inserted pages of the previous page-sequence.
• insert a getFocePageCount method to get the private variable.
• insert a getInitialPageNumber method to get the private variable.

Open issues / questions:

• i think it very likely that the previousPageSeqLM variable of
  the Root class should be privat and there should be a
  setPreviousPageSeqLM and a getPreviousPageSeqLM method to
  hand the variable into and out of the object.
• there was a second possiblity to implement this all
  by using the AreaTreeHandler:

• instead of saving the PageSequenceLayoutManger object
  at the end of the finishLayout method of the
  PageSequenceLayoutManger it could be preserved at the
  end of the endPageSequence method of the AreaTreeHandler.
• instead of calling the checkForcePageCount from the
  startOfNode method of PageSequence it could be called
  from the startPageSequence method of the AreaTreeHandler
  after receiving the rootFObj.
• all other could be left nearly as with this patch with
  the exception that the startingPageNumber of the PageSequence
  has to be recalced after calling the checkForcePageCount
  because it is already calced at this point and does not
  know about possibly inserted pages from the
  checkForcePageCount method before.
  someone who has a more overall sight of the code has to
  decide where it fits best.

I know the force-page-count property is of low priority, but
it would be nice to get feedback, if someone can spare time
to have a look at this patch.

I hope i was not too verbose and that my patch is more
usefull than the review is time-consuming and that i dont
violate too much design guidelines.

happy new year
gerhard