Package org.apache.fop.layoutmgr
Class AbstractBreaker
java.lang.Object
org.apache.fop.layoutmgr.AbstractBreaker
- Direct Known Subclasses:
LocalBreaker,PageBreaker
Abstract base class for breakers (page breakers, static region handlers etc.).
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionstatic classHelper class, extending the functionality of the basicBlockKnuthSequence.static classstatic classA page break position. -
Field Summary
FieldsModifier and TypeFieldDescriptionprotected intdesired text alignmentprotected intblockListIndex of the current BlockSequence in blockListsprotected List<AbstractBreaker.BlockSequence> protected List<ListElement> protected MinOptMaxfootnote separator lengthprotected static final org.apache.commons.logging.Loglogging instanceprotected LayoutManagerprotected Positionprotected PageSequenceLayoutManager -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionprotected voidaddAreas(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int startPart, int partCount, AbstractBreaker.BlockSequence originalList, AbstractBreaker.BlockSequence effectiveList) protected voidaddAreas(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int startPart, int partCount, AbstractBreaker.BlockSequence originalList, AbstractBreaker.BlockSequence effectiveList, LayoutContext childLC) Phase 3 of Knuth algorithm: Adds the areasprotected voidaddAreas(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int partCount, AbstractBreaker.BlockSequence originalList, AbstractBreaker.BlockSequence effectiveList) Phase 3 of Knuth algorithm: Adds the areasprotected abstract voidaddAreas(PositionIterator posIter, LayoutContext context) Tell the layout manager to add all the child areas implied by Position objects which will be returned by the Iterator.protected voidaddAreasForFloats(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int startPart, int partCount, AbstractBreaker.BlockSequence originalList, AbstractBreaker.BlockSequence effectiveList, LayoutContext childLC, int lastBreak, int startElementIndex, int endElementIndex) protected booleancontainsNonRestartableLM(Position position) Returnstrueif the given position or one of its descendants corresponds to a non-restartable LM.protected LayoutContextCreates the top-level LayoutContext for the breaker operation.protected org.apache.fop.layoutmgr.PageBreakingAlgorithm.PageBreakingLayoutListenerCreates and returns a PageBreakingLayoutListener for the PageBreakingAlgorithm to notify about layout problems.booleandoLayout(int flowBPD, boolean autoHeight) Starts the page breaking process.protected abstract voiddoPhase3(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int partCount, AbstractBreaker.BlockSequence originalList, AbstractBreaker.BlockSequence effectiveList) Phase 3 of Knuth algorithm: Adds the areasprotected abstract voidfinishPart(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, AbstractBreaker.PageBreakPosition pbp) Finish part.protected abstract LayoutManagerprotected abstract intprotected intgetNextBlockList(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 intgetNextBlockList(LayoutContext childLC, int nextSequenceStartsOn, Position positionAtIPDChange, LayoutManager restartAtLM, List<ListElement> firstElements) Gets the next block list (sequence) and adds it to a list of block lists if it's not empty.protected abstract List<ListElement> getNextKnuthElements(LayoutContext context, int alignment) Get a sequence of KnuthElements representing the content of the node assigned to the LMprotected List<ListElement> getNextKnuthElements(LayoutContext context, int alignment, Position positionAtIPDChange, LayoutManager restartAtLM) Get a sequence of KnuthElements representing the content of the node assigned to the LMprotected PageProviderReturns the PageProvider if any.protected abstract LayoutManagerprotected voidThis method is called when no content is available for a part.protected inthandleFloatLayout(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int optimalPageCount, AbstractBreaker.BlockSequence blockList, LayoutContext childLC) protected inthandleSpanChange(LayoutContext childLC, int nextSequenceStartsOn) Handles span changes reported through theLayoutContext.protected abstract booleanbooleanisEmpty()protected booleanControls the behaviour of the algorithm in cases where the first element of a part overflows a line/page.protected booleanprotected booleanlastPageHasIPDChange(int optimalPageCount) protected voidobserveElementList(List elementList) Used for debugging purposes.protected voidprepareToRedoLayout(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int partCount, AbstractBreaker.BlockSequence originalList, AbstractBreaker.BlockSequence effectiveList) protected booleanprotected voidstartPart(AbstractBreaker.BlockSequence list, int breakClass, boolean emptyContent) Start part.protected voidupdateLayoutContext(LayoutContext context) Used to update the LayoutContext in subclasses prior to starting a new element list.protected boolean
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Field Details
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log
protected static final org.apache.commons.logging.Log loglogging instance -
originalRestartAtLM
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positionAtBreak
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firstElementsForRestart
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pslm
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blockLists
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blockListIndex
protected int blockListIndexblockListIndex of the current BlockSequence in blockLists -
alignment
protected int alignmentdesired text alignment -
footnoteSeparatorLength
footnote separator length
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Constructor Details
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AbstractBreaker
public AbstractBreaker()
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Method Details
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getCurrentDisplayAlign
protected abstract int getCurrentDisplayAlign()- Returns:
- current display alignment
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hasMoreContent
protected abstract boolean hasMoreContent()- Returns:
- true if content not exhausted
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addAreas
Tell the layout manager to add all the child areas implied by Position objects which will be returned by the Iterator.- Parameters:
posIter- the position iteratorcontext- the context
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getTopLevelLM
- Returns:
- top level layout manager
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getCurrentChildLM
- Returns:
- current child layout manager
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isPartOverflowRecoveryActivated
protected boolean isPartOverflowRecoveryActivated()Controls the behaviour of the algorithm in cases where the first element of a part overflows a line/page.- Returns:
- true if the algorithm should try to send the element to the next line/page.
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isSinglePartFavored
protected boolean isSinglePartFavored()- Returns:
- true if one a single part should be produced if possible (ex. for block-containers)
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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.- Returns:
- the applicable PageProvider, or null if not applicable
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createLayoutListener
protected org.apache.fop.layoutmgr.PageBreakingAlgorithm.PageBreakingLayoutListener createLayoutListener()Creates and returns a PageBreakingLayoutListener for the PageBreakingAlgorithm to notify about layout problems.- Returns:
- the listener instance or null if no notifications are needed
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getNextKnuthElements
Get a sequence of KnuthElements representing the content of the node assigned to the LM- Parameters:
context- the LayoutContext used to store layout informationalignment- the desired text alignment- Returns:
- the list of KnuthElements
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getNextKnuthElements
protected List<ListElement> getNextKnuthElements(LayoutContext context, int alignment, Position positionAtIPDChange, LayoutManager restartAtLM) Get a sequence of KnuthElements representing the content of the node assigned to the LM- Parameters:
context- the LayoutContext used to store layout informationalignment- the desired text alignmentpositionAtIPDChange- last element on the part before an IPD changerestartAtLM- the layout manager from which to restart, if IPD change occurs between two LMs- Returns:
- the list of KnuthElements
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isEmpty
public boolean isEmpty()- Returns:
- true if there's no content that could be handled.
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startPart
Start part.- Parameters:
list- a block sequencebreakClass- a break class
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handleEmptyContent
protected void handleEmptyContent()This method is called when no content is available for a part. Used to force empty pages. -
finishPart
protected abstract void finishPart(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, AbstractBreaker.PageBreakPosition pbp) Finish part.- Parameters:
alg- a page breaking algorithmpbp- a page break posittion
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createLayoutContext
Creates the top-level LayoutContext for the breaker operation.- Returns:
- the top-level LayoutContext
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updateLayoutContext
Used to update the LayoutContext in subclasses prior to starting a new element list.- Parameters:
context- the LayoutContext to update
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observeElementList
Used for debugging purposes. Notifies all registered observers about the element list. Override to set different parameters.- Parameters:
elementList- the Knuth element list
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doLayout
public boolean doLayout(int flowBPD, boolean autoHeight) Starts the page breaking process.- Parameters:
flowBPD- the constant available block-progression-dimension (used for every part)autoHeight- true if warnings about overflows should be disabled because the the BPD is really undefined (for footnote-separators, for example)
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containsNonRestartableLM
Returnstrueif the given position or one of its descendants corresponds to a non-restartable LM.- Parameters:
position- a position- Returns:
trueif there is a non-restartable LM in the hierarchy
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doPhase3
protected abstract void doPhase3(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int partCount, AbstractBreaker.BlockSequence originalList, AbstractBreaker.BlockSequence effectiveList) Phase 3 of Knuth algorithm: Adds the areas- Parameters:
alg- PageBreakingAlgorithm instance which determined the breakspartCount- number of parts (pages) to be renderedoriginalList- original Knuth element listeffectiveList- effective Knuth element list (after adjustments)
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addAreas
protected void addAreas(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int partCount, AbstractBreaker.BlockSequence originalList, AbstractBreaker.BlockSequence effectiveList) Phase 3 of Knuth algorithm: Adds the areas- Parameters:
alg- PageBreakingAlgorithm instance which determined the breakspartCount- number of parts (pages) to be renderedoriginalList- original Knuth element listeffectiveList- effective Knuth element list (after adjustments)
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addAreas
protected void addAreas(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int startPart, int partCount, AbstractBreaker.BlockSequence originalList, AbstractBreaker.BlockSequence effectiveList) -
addAreas
protected void addAreas(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int startPart, int partCount, AbstractBreaker.BlockSequence originalList, AbstractBreaker.BlockSequence effectiveList, LayoutContext childLC) Phase 3 of Knuth algorithm: Adds the areas- Parameters:
alg- PageBreakingAlgorithm instance which determined the breaksstartPart- index of the first part (page) to be renderedpartCount- number of parts (pages) to be renderedoriginalList- original Knuth element listeffectiveList- effective Knuth element list (after adjustments)
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handleSpanChange
Handles span changes reported through theLayoutContext. Only used by the PSLM and called bygetNextBlockList().- Parameters:
childLC- the LayoutContextnextSequenceStartsOn- previous value for break handling- Returns:
- effective value for break handling
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getNextBlockList
Gets the next block list (sequence) and adds it to a list of block lists if it's not empty.- Parameters:
childLC- LayoutContext to usenextSequenceStartsOn- indicates on what page the next sequence should start- Returns:
- the page on which the next content should appear after a hard break
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getNextBlockList
protected int getNextBlockList(LayoutContext childLC, int nextSequenceStartsOn, Position positionAtIPDChange, LayoutManager restartAtLM, List<ListElement> firstElements) Gets the next block list (sequence) and adds it to a list of block lists if it's not empty.- Parameters:
childLC- LayoutContext to usenextSequenceStartsOn- indicates on what page the next sequence should startpositionAtIPDChange- last element on the part before an IPD changerestartAtLM- the layout manager from which to restart, if IPD change occurs between two LMsfirstElements- elements from non-restartable LMs on the new page- Returns:
- the page on which the next content should appear after a hard break
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shouldRedoLayout
protected boolean shouldRedoLayout() -
prepareToRedoLayout
protected void prepareToRedoLayout(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int partCount, AbstractBreaker.BlockSequence originalList, AbstractBreaker.BlockSequence effectiveList) -
wasLayoutRedone
protected boolean wasLayoutRedone() -
lastPageHasIPDChange
protected boolean lastPageHasIPDChange(int optimalPageCount) -
handleFloatLayout
protected int handleFloatLayout(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int optimalPageCount, AbstractBreaker.BlockSequence blockList, LayoutContext childLC) -
addAreasForFloats
protected void addAreasForFloats(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int startPart, int partCount, AbstractBreaker.BlockSequence originalList, AbstractBreaker.BlockSequence effectiveList, LayoutContext childLC, int lastBreak, int startElementIndex, int endElementIndex)
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