org.apache.fop.area

## Class AreaTreeHandler

- java.lang.Object
- - org.apache.fop.fo.FOEventHandler
  - - org.apache.fop.area.AreaTreeHandler

    public class AreaTreeHandler
    extends FOEventHandler

Area tree handler for formatting objects. Concepts: The area tree is to be as small as possible. With minimal classes and data to fully represent an area tree for formatting objects. The area tree needs to be simple to render and follow the spec closely. This area tree has the concept of page sequences. Wherever possible information is discarded or optimized to keep memory use low. The data is also organized to make it possible for renderers to minimize their output. A page can be saved if not fully resolved and once rendered a page contains only size and id reference information. The area tree pages are organized in a model that depends on the type of renderer.

### Field Summary

Fields
`protected AreaTreeModel` `model` The AreaTreeModel in use

### Fields inherited from class org.apache.fop.fo.FOEventHandler

`fontInfo, foUserAgent`

### Constructor Summary

Constructors
Constructor and Description
`AreaTreeHandler(FOUserAgent userAgent, String outputFormat, OutputStream stream)` Constructor.

### Method Summary

All Methods Instance Methods Concrete Methods Deprecated Methods
`void` `addUnresolvedIDRef(String idref, Resolvable res)` Deprecated. use getIDTracker().addUnresolvedIDRef(idref, res) instead
`boolean` `alreadyResolvedID(String id)` Deprecated. use getIDTracker().alreadyResolvedID(id) instead
`void` `associateIDWithPageViewport(String id, PageViewport pv)` Deprecated. use getIDTracker().associateIDWithPageViewport(id, pv) instead
`void` `endDocument()` End the document.
`void` `endExternalDocument(ExternalDocument document)` Process the end of the external-document extension.
`void` `endPageSequence(PageSequence pageSequence)` End the PageSequence.
`String` `generatePageViewportKey()` Generates and returns a unique key for a page viewport.
`AreaTreeModel` `getAreaTreeModel()` Get the area tree model for this area tree.
`IDTracker` `getIDTracker()` Get the IDTracker for this area tree.
`LayoutManagerMaker` `getLayoutManagerMaker()` Get the LayoutManager maker for this area tree.
`List<PageViewport>` `getPageViewportsContainingID(String id)` Deprecated. use getIDTracker().getPageViewportsContainingID(id) instead
`FormattingResults` `getResults()` Get information about the rendered output, like number of pages created.
`boolean` `isComplexScriptFeaturesEnabled()` Check whether complex script features are enabled.
`void` `notifyPageSequenceFinished(AbstractPageSequence pageSequence, int pageCount)` Called by the PageSequenceLayoutManager when it is finished with a page-sequence.
`protected void` `setupModel(FOUserAgent userAgent, String outputFormat, OutputStream stream)` Sets up the AreaTreeModel instance for use by the AreaTreeHandler.
`void` `signalIDProcessed(String id)` Deprecated. use getIDTracker().signalIDProcessed(id) instead
`void` `signalPendingID(String id)` Deprecated. use getIDTracker().signalPendingID(id) instead
`void` `startDocument()` Prepare AreaTreeHandler for document processing This is called from FOTreeBuilder.startDocument()
`void` `startExternalDocument(ExternalDocument document)` Process the start of the external-document extension.
`void` `startPageSequence(PageSequence pageSequence)`
`void` `startRoot(Root root)` Called upon start of root element.
`void` `tryIDResolution(PageViewport pv)` Deprecated. use getIDTracker().tryIDResolution(pv) instead

### Methods inherited from class org.apache.fop.fo.FOEventHandler

`character, characters, endBlock, endBlockContainer, endBody, endCell, endColumn, endFlow, endFooter, endFootnote, endFootnoteBody, endHeader, endInline, endInstreamForeignObject, endLeader, endLink, endList, endListBody, endListItem, endListLabel, endMarkup, endPageNumber, endPageNumberCitation, endPageNumberCitationLast, endRetrieveMarker, endRetrieveTableMarker, endRoot, endRow, endStatic, endTable, endWrapper, getFontInfo, getUserAgent, image, pageRef, restoreState, restoreState, startBlock, startBlockContainer, startBody, startCell, startColumn, startFlow, startFooter, startFootnote, startFootnoteBody, startHeader, startInline, startInstreamForeignObject, startLeader, startLink, startList, startListBody, startListItem, startListLabel, startMarkup, startPageNumber, startPageNumberCitation, startPageNumberCitationLast, startRetrieveMarker, startRetrieveTableMarker, startRow, startStatic, startTable, startWrapper`

### Methods inherited from class java.lang.Object

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

### Field Detail

#### model

    protected AreaTreeModel model

The AreaTreeModel in use

### Constructor Detail

#### AreaTreeHandler

    public AreaTreeHandler(FOUserAgent userAgent,
                           String outputFormat,
                           OutputStream stream)
                    throws FOPException

Constructor.

Parameters:
  `userAgent` - FOUserAgent object for process
  `outputFormat` - the MIME type of the output format to use (ex. "application/pdf").
  `stream` - OutputStream
Throws:
  `FOPException` - if the RenderPagesModel cannot be created

### Method Detail

#### setupModel

    protected void setupModel(FOUserAgent userAgent,
                              String outputFormat,
                              OutputStream stream)
                       throws FOPException

Sets up the AreaTreeModel instance for use by the AreaTreeHandler.

Parameters:
  `userAgent` - FOUserAgent object for process
  `outputFormat` - the MIME type of the output format to use (ex. "application/pdf").
  `stream` - OutputStream
Throws:
  `FOPException` - if the RenderPagesModel cannot be created

#### getAreaTreeModel

    public AreaTreeModel getAreaTreeModel()

Get the area tree model for this area tree.

Returns:
  AreaTreeModel the model being used for this area tree

#### getLayoutManagerMaker

    public LayoutManagerMaker getLayoutManagerMaker()

Get the LayoutManager maker for this area tree.

Returns:
  LayoutManagerMaker the LayoutManager maker being used for this area tree

#### getIDTracker

    public IDTracker getIDTracker()

Get the IDTracker for this area tree.

Returns:
  IDTracker used to track reference ids for items in this area tree

#### getResults

    public FormattingResults getResults()

Get information about the rendered output, like number of pages created.

Overrides:
  `getResults` in class `FOEventHandler`
Returns:
  the results structure

#### isComplexScriptFeaturesEnabled

    public boolean isComplexScriptFeaturesEnabled()

Check whether complex script features are enabled.

Returns:
  true if using complex script features

#### startDocument

    public void startDocument()
                       throws SAXException

Prepare AreaTreeHandler for document processing This is called from FOTreeBuilder.startDocument()

Overrides:
  `startDocument` in class `FOEventHandler`
Throws:
  `SAXException` - if there is an error

#### startRoot

    public void startRoot(Root root)

Description copied from class: `FOEventHandler`
Called upon start of root element.

Overrides:
  `startRoot` in class `FOEventHandler`
Parameters:
  `root` - element

#### startPageSequence

    public void startPageSequence(PageSequence pageSequence)

Overrides:
  `startPageSequence` in class `FOEventHandler`
Parameters:
  `pageSequence` - PageSequence that is starting.

#### endPageSequence

    public void endPageSequence(PageSequence pageSequence)

End the PageSequence. The PageSequence formats Pages and adds them to the AreaTree. The area tree then handles what happens with the pages.

Overrides:
  `endPageSequence` in class `FOEventHandler`
Parameters:
  `pageSequence` - the page sequence ending

#### startExternalDocument

    public void startExternalDocument(ExternalDocument document)

Process the start of the external-document extension.

Overrides:
  `startExternalDocument` in class `FOEventHandler`
Parameters:
  `document` - the external-document node

#### endExternalDocument

    public void endExternalDocument(ExternalDocument document)

Process the end of the external-document extension.

Overrides:
  `endExternalDocument` in class `FOEventHandler`
Parameters:
  `document` - the external-document node

#### notifyPageSequenceFinished

    public void notifyPageSequenceFinished(AbstractPageSequence pageSequence,
                                           int pageCount)

Called by the PageSequenceLayoutManager when it is finished with a page-sequence.

Parameters:
  `pageSequence` - the page-sequence just finished
  `pageCount` - The number of pages generated for the page-sequence

#### endDocument

    public void endDocument()
                     throws SAXException

End the document.

Overrides:
  `endDocument` in class `FOEventHandler`
Throws:
  `SAXException` - if there is some error

#### generatePageViewportKey

    public String generatePageViewportKey()

Generates and returns a unique key for a page viewport.

Returns:
  the generated key.

#### associateIDWithPageViewport

    @Deprecated
    public void associateIDWithPageViewport(String id,
                                                        PageViewport pv)

Deprecated. use getIDTracker().associateIDWithPageViewport(id, pv) instead
Tie a PageViewport with an ID found on a child area of the PV. Note that an area with a given ID may be on more than one PV, hence an ID may have more than one PV associated with it.

Parameters:
  `id` - the property ID of the area
  `pv` - a page viewport that contains the area with this ID

#### signalPendingID

    @Deprecated
    public void signalPendingID(String id)

Deprecated. use getIDTracker().signalPendingID(id) instead
This method tie an ID to the areaTreeHandler until this one is ready to be processed. This is used in page-number-citation-last processing so we know when an id can be resolved.

Parameters:
  `id` - the id of the object being processed

#### signalIDProcessed

    @Deprecated
    public void signalIDProcessed(String id)

Deprecated. use getIDTracker().signalIDProcessed(id) instead
Signals that all areas for the formatting object with the given ID have been generated. This is used to determine when page-number-citation-last ref-ids can be resolved.

Parameters:
  `id` - the id of the formatting object which was just finished

#### alreadyResolvedID

    @Deprecated
    public boolean alreadyResolvedID(String id)

Deprecated. use getIDTracker().alreadyResolvedID(id) instead
Check if an ID has already been resolved

Parameters:
  `id` - the id to check
Returns:
  true if the ID has been resolved

#### tryIDResolution

    @Deprecated
    public void tryIDResolution(PageViewport pv)

Deprecated. use getIDTracker().tryIDResolution(pv) instead
Tries to resolve all unresolved ID references on the given page.

Parameters:
  `pv` - page viewport whose ID refs to resolve

#### getPageViewportsContainingID

    @Deprecated
    public List<PageViewport> getPageViewportsContainingID(String id)

Deprecated. use getIDTracker().getPageViewportsContainingID(id) instead
Get the set of page viewports that have an area with a given id.

Parameters:
  `id` - the id to lookup
Returns:
  the list of PageViewports

#### addUnresolvedIDRef

    @Deprecated
    public void addUnresolvedIDRef(String idref,
                                               Resolvable res)

Deprecated. use getIDTracker().addUnresolvedIDRef(idref, res) instead
Add an Resolvable object with an unresolved idref

Parameters:
  `idref` - the idref whose target id has not yet been located
  `res` - the Resolvable object needing the idref to be resolved