org.apache.fop.layoutmgr
Class PageBreaker

java.lang.Object
  org.apache.fop.layoutmgr.AbstractBreaker
      org.apache.fop.layoutmgr.PageBreaker

public class PageBreaker
extends AbstractBreaker

Handles the breaking of pages in an fo:flow

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.fop.layoutmgr.AbstractBreaker

AbstractBreaker.BlockSequence, AbstractBreaker.PageBreakPosition

Field Summary

Fields inherited from class org.apache.fop.layoutmgr.AbstractBreaker

alignment, footnoteSeparatorLength, log

Constructor Summary

PageBreaker(PageSequenceLayoutManager pslm)

Method Summary

protected void	addAreas(PositionIterator posIter, LayoutContext context) Adds an area to the flow layout manager
protected PageBreakingAlgorithm.PageBreakingLayoutListener	createLayoutListener() Creates and returns a PageBreakingLayoutListener for the PageBreakingAlgorithm to notify about layout problems.
protected void	doPhase3(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int partCount, AbstractBreaker.BlockSequence originalList, AbstractBreaker.BlockSequence effectiveList) Phase 3 of Knuth algorithm: Adds the areas
protected void	finishPart(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, AbstractBreaker.PageBreakPosition pbp)
protected LayoutManager	getCurrentChildLM()
protected int	getCurrentDisplayAlign()
protected int	getNextBlockList(LayoutContext childLC, int nextSequenceStartsOn) Gets the next block list (sequence) and adds it to a list of block lists if it's not empty.
protected java.util.List	getNextKnuthElements(LayoutContext context, int alignment)
protected PageProvider	getPageProvider() Returns the PageProvider if any.
protected LayoutManager	getTopLevelLM()
protected void	handleEmptyContent() This method is called when no content is available for a part.
protected int	handleSpanChange(LayoutContext childLC, int nextSequenceStartsOn) Handles span changes reported through the LayoutContext.
protected boolean	hasMoreContent()
protected void	observeElementList(java.util.List elementList) Used for debugging purposes.
protected void	startPart(AbstractBreaker.BlockSequence list, int breakClass)
protected void	updateLayoutContext(LayoutContext context) Used to update the LayoutContext in subclasses prior to starting a new element list.

Methods inherited from class org.apache.fop.layoutmgr.AbstractBreaker

addAreas, addAreas, createLayoutContext, doLayout, doLayout, isEmpty, isPartOverflowRecoveryActivated, isSinglePartFavored

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PageBreaker

public PageBreaker(PageSequenceLayoutManager pslm)

Method Detail

updateLayoutContext

protected void updateLayoutContext(LayoutContext context)

Used to update the LayoutContext in subclasses prior to starting a new element list.

Overrides:

updateLayoutContext in class AbstractBreaker

Parameters:

context - the LayoutContext to update

getTopLevelLM

protected LayoutManager getTopLevelLM()

Specified by:

getTopLevelLM in class AbstractBreaker

getPageProvider

protected PageProvider getPageProvider()

Returns the PageProvider if any. PageBreaker overrides this method because each page may have a different available BPD which needs to be accessible to the breaking algorithm.

Overrides:

getPageProvider in class AbstractBreaker

Returns:

the applicable PageProvider, or null if not applicable

createLayoutListener

protected PageBreakingAlgorithm.PageBreakingLayoutListener createLayoutListener()

Creates and returns a PageBreakingLayoutListener for the PageBreakingAlgorithm to notify about layout problems.

Overrides:

createLayoutListener in class AbstractBreaker

Returns:

the listener instance or null if no notifications are needed

handleSpanChange

protected int handleSpanChange(LayoutContext childLC,
                               int nextSequenceStartsOn)

Handles span changes reported through the LayoutContext. Only used by the PSLM and called by getNextBlockList().

Overrides:

handleSpanChange in class AbstractBreaker

Parameters:

childLC - the LayoutContext

nextSequenceStartsOn - previous value for break handling

Returns:

effective value for break handling

getNextBlockList

protected int getNextBlockList(LayoutContext childLC,
                               int nextSequenceStartsOn)

Gets the next block list (sequence) and adds it to a list of block lists if it's not empty.

Overrides:

getNextBlockList in class AbstractBreaker

Parameters:

childLC - LayoutContext to use

nextSequenceStartsOn - indicates on what page the next sequence should start

Returns:

the page on which the next content should appear after a hard break

getNextKnuthElements

protected java.util.List getNextKnuthElements(LayoutContext context,
                                              int alignment)

Specified by:

getNextKnuthElements in class AbstractBreaker

getCurrentDisplayAlign

protected int getCurrentDisplayAlign()

Specified by:

getCurrentDisplayAlign in class AbstractBreaker

Returns:

current display alignment

hasMoreContent

protected boolean hasMoreContent()

Specified by:

hasMoreContent in class AbstractBreaker

Returns:

whether or not this flow has more page break opportunities

addAreas

protected void addAreas(PositionIterator posIter,
                        LayoutContext context)

Adds an area to the flow layout manager

Specified by:

addAreas in class AbstractBreaker

Parameters:

posIter - the position iterator

context - the layout context

doPhase3

protected void doPhase3(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg,
                        int partCount,
                        AbstractBreaker.BlockSequence originalList,
                        AbstractBreaker.BlockSequence effectiveList)

Phase 3 of Knuth algorithm: Adds the areas This implementation checks whether to trigger column-balancing, or whether to take into account a 'last-page' condition.

Specified by:

doPhase3 in class AbstractBreaker

Parameters:

alg - PageBreakingAlgorithm instance which determined the breaks

partCount - number of parts (pages) to be rendered

originalList - original Knuth element list

effectiveList - effective Knuth element list (after adjustments)

startPart

protected void startPart(AbstractBreaker.BlockSequence list,
                         int breakClass)

Overrides:

startPart in class AbstractBreaker

handleEmptyContent

protected void handleEmptyContent()

This method is called when no content is available for a part. Used to force empty pages.

Overrides:

handleEmptyContent in class AbstractBreaker

finishPart

protected void finishPart(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg,
                          AbstractBreaker.PageBreakPosition pbp)

Specified by:

finishPart in class AbstractBreaker

getCurrentChildLM

protected LayoutManager getCurrentChildLM()

Specified by:

getCurrentChildLM in class AbstractBreaker

Returns:

the current child flow layout manager

observeElementList

protected void observeElementList(java.util.List elementList)

Used for debugging purposes. Notifies all registered observers about the element list. Override to set different parameters.

Overrides:

observeElementList in class AbstractBreaker

Parameters:

elementList - the Knuth element list