edu.harvard.hul.ois.jhove.module.pdf

Class PageLabelNode

java.lang.Object

edu.harvard.hul.ois.jhove.module.pdf.PageLabelNode

public class PageLabelNode
extends Object

Class for nodes of a PDF number tree.

Field Summary

Fields

Modifier and Type	Field and Description
protected PdfDictionary	_dict The dictionary which defines this node.
protected PdfModule	_module The PdfModule this node is associated with.
protected PageLabelNode	_parent The parent node of this node.
protected boolean	_walkFinished Set to true when all subnodes of this node have been iterated through following a StartWalk.

Constructor Summary

Constructors

Constructor and Description
PageLabelNode(PdfModule module, PageLabelNode parent, PdfDictionary dict) Superclass constructor.

Method Summary

Modifier and Type	Method and Description
PdfObject	_getCurrentValue() Returns value associated with current key
void	buildSubtree() Build the subtree of descendants of this node, using the Kids entry in the dictionary.
boolean	findNextKeyValue() Obtain the next key-value pair from the tree.
int	getCurrentKey() Returns key at current position in traversing tree
int	getPrevKey() Returns key previously obtained in traversing tree
PdfObject	getPrevValue() Returns value associated with key previously obtained in traversing tree
static String	intToBase26(int n, boolean upperCase) A convenience method to turn integers into "letter" page numbers as defined for PDF.
static String	intToRoman(int n, boolean upperCase) A convenience method to turn integers into Roman numerals, for the generation of page labels.
PageLabelNode	nextLeafObject() Get the next leaf object which is under this node.
void	startWalk() Initialize an iterator through the descendants of this node.

Methods inherited from class java.lang.Object

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

Field Detail

_module

protected PdfModule _module

The PdfModule this node is associated with.

_parent

protected PageLabelNode _parent

The parent node of this node.

_dict

protected PdfDictionary _dict

The dictionary which defines this node.

_walkFinished

protected boolean _walkFinished

Set to true when all subnodes of this node have been iterated through following a StartWalk.

Constructor Detail

PageLabelNode

public PageLabelNode(PdfModule module,
                     PageLabelNode parent,
                     PdfDictionary dict)

Superclass constructor.

Parameters:

module - The PdfModule under which we're operating

parent - The parent node in the document tree; may be null only for the root node

dict - The dictionary object on which this node is based

Method Detail

buildSubtree

public void buildSubtree()
                  throws PdfException

Build the subtree of descendants of this node, using the Kids entry in the dictionary. Leaf nodes are recognized by not having a Kids entry.

Throws:

PdfException

startWalk

public void startWalk()

Initialize an iterator through the descendants of this node.

nextLeafObject

public PageLabelNode nextLeafObject()

Get the next leaf object which is under this node. This function is designed such that calling startWalk() and then repeatedly calling nextLeafObject() will return all the leaf objects in the tree under this node, and finally will return null when there are no more. A leaf object is one which has no Kids; it is required to have a Nums entry.

findNextKeyValue

public boolean findNextKeyValue()
                         throws PdfException

Obtain the next key-value pair from the tree. This returns true if a pair is available, false if not. After this is called, getCurrentKey and getCurrentValue may be called to retrieve the key and value thus found. Each time this is called, currentKey and currentValue get copied into prevKey and prevValue.

Throws:

PdfException

getCurrentKey

public int getCurrentKey()

Returns key at current position in traversing tree

_getCurrentValue

public PdfObject _getCurrentValue()

Returns value associated with current key

getPrevKey

public int getPrevKey()

Returns key previously obtained in traversing tree

getPrevValue

public PdfObject getPrevValue()

Returns value associated with key previously obtained in traversing tree

intToRoman

public static String intToRoman(int n,
                                boolean upperCase)

A convenience method to turn integers into Roman numerals, for the generation of page labels.

intToBase26

public static String intToBase26(int n,
                                 boolean upperCase)

A convenience method to turn integers into "letter" page numbers as defined for PDF. The first 26 pages are A-Z, the next 26 AA-ZZ, etc.