com.aspose.words

Class LayoutCollector

java.lang.Object

com.aspose.words.LayoutCollector

public class LayoutCollector
extends java.lang.Object

This class allows to compute page numbers of document nodes.

To learn more, visit the Converting to Fixed-page Format documentation article.

When you create a LayoutCollector and specify a Document document object to attach to, the collector will record mapping of document nodes to layout objects when the document is formatted into pages.

You will be able to find out on which page a particular document node (e.g. run, paragraph or table cell) is located by using the getStartPageIndex(com.aspose.words.Node), getEndPageIndex(com.aspose.words.Node) and getNumPagesSpanned(com.aspose.words.Node) methods. These methods automatically build page layout model of the document and update fields if required.

When you no longer need to collect layout information, it is best to set the getDocument() / setDocument(com.aspose.words.Document) property to null to avoid unnecessary collection of more layout mappings.

Constructor Summary

Constructors

Constructor and Description
LayoutCollector(Document doc) Initializes an instance of this class.

Method Summary

Modifier and Type	Method and Description
void	clear() Clears all collected layout data.
Document	getDocument() Gets the document this collector instance is attached to.
int	getEndPageIndex(Node node) Gets 1-based index of the page where node ends.
java.lang.Object	getEntity(Node node) Returns an opaque position of the LayoutEnumerator which corresponds to the specified node.
int	getNumPagesSpanned(Node node) Gets number of pages the specified node spans.
int	getStartPageIndex(Node node) Gets 1-based index of the page where node begins.
void	setDocument(Document value) Sets the document this collector instance is attached to.

Methods inherited from class java.lang.Object

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

Constructor Detail

LayoutCollector

public LayoutCollector(Document doc)

Initializes an instance of this class.

Parameters:

doc - The document to which this collector instance will be attached to.

Method Detail

getStartPageIndex

public int getStartPageIndex(Node node)
                      throws java.lang.Exception

Gets 1-based index of the page where node begins. Returns 0 if node cannot be mapped to a page.

Throws:

java.lang.Exception

getEndPageIndex

public int getEndPageIndex(Node node)
                    throws java.lang.Exception

Gets 1-based index of the page where node ends. Returns 0 if node cannot be mapped to a page.

Throws:

java.lang.Exception

getNumPagesSpanned

public int getNumPagesSpanned(Node node)
                       throws java.lang.Exception

Gets number of pages the specified node spans. 0 if node is within a single page. This is the same as getEndPageIndex(com.aspose.words.Node) - getStartPageIndex(com.aspose.words.Node).

Throws:

java.lang.Exception

clear

public void clear()

Clears all collected layout data. Call this method after document was manually updated, or layout was rebuilt.

getDocument

public Document getDocument()

Gets the document this collector instance is attached to. If you need to access page indexes of the document nodes you need to set this property to point to a document instance, before page layout of the document is built. It is best to set this property to null afterwards, otherwise the collector continues to accumulate information from subsequent rebuilds of the document's page layout.

Returns:

The document this collector instance is attached to.

setDocument

public void setDocument(Document value)

Sets the document this collector instance is attached to. If you need to access page indexes of the document nodes you need to set this property to point to a document instance, before page layout of the document is built. It is best to set this property to null afterwards, otherwise the collector continues to accumulate information from subsequent rebuilds of the document's page layout.

Parameters:

value - The document this collector instance is attached to.

getEntity

public java.lang.Object getEntity(Node node)
                           throws java.lang.Exception

Returns an opaque position of the LayoutEnumerator which corresponds to the specified node. You can use returned value as an argument to LayoutEnumerator.getCurrent() / LayoutEnumerator.setCurrent(java.lang.Object) given the document being enumerated and the document of the node are the same.

This method works for only Paragraph nodes, as well as indivisible inline nodes, e.g. BookmarkStart or Shape. It doesn't work for Run, Cell Row or Table nodes, and nodes within header/footer.

Note that the entity returned for a Paragraph node is a paragraph break span. Use the appropriate method to ascend to the parent line

If you need to navigate to a Run of text then you can insert bookmark right before it and then navigate to the bookmark instead.

If you need to navigate to a Cell node then you can move to a Paragraph node in this cell and then ascend to a parent entity. The same approach can be used for Row and Table nodes.

Throws:

java.lang.Exception