fop 1.0

org.apache.fop.layoutmgr
Class PageBreaker

java.lang.Object
  extended by org.apache.fop.layoutmgr.AbstractBreaker
      extended by 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  int getNextBlockList(LayoutContext childLC, int nextSequenceStartsOn, Position positionAtIPDChange, LayoutManager restartLM, java.util.List firstElements)
          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  java.util.List getNextKnuthElements(LayoutContext context, int alignment, Position positionAtIPDChange, LayoutManager restartAtLM)
          
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, 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

getNextBlockList

protected int getNextBlockList(LayoutContext childLC,
                               int nextSequenceStartsOn,
                               Position positionAtIPDChange,
                               LayoutManager restartLM,
                               java.util.List firstElements)
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
positionAtIPDChange - last element on the part before an IPD change
restartLM - the layout manager from which to restart, if IPD change occurs between two LMs
firstElements - elements from non-restartable LMs on the new page
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

getNextKnuthElements

protected java.util.List getNextKnuthElements(LayoutContext context,
                                              int alignment,
                                              Position positionAtIPDChange,
                                              LayoutManager restartAtLM)

Overrides:
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

fop 1.0

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