com.etymon.pjx

Interface PdfObjectFilter

All Known Implementing Classes:

PdfPageObjects, PdfReferencedObjects, PdfRenumberOffset

public interface PdfObjectFilter

A filtering function that allows examining and modifying PDF objects recursively. PdfObject.filter(PdfObjectFilter) passes each object through preFilter(PdfObject) before descending recursively into the object's contents (if it is a container such as PdfArray or PdfDictionary). It then passes the (possibly modified) object through postFilter(PdfObject) for a second opportunity to examine or modify the object. The modified object is not required to be of the same type as the original object.

Method Summary

Modifier and Type	Method and Description
PdfObject	postFilter(PdfObject obj) Examines a PDF object and optionally returns a modified object.
PdfObject	preFilter(PdfObject obj) Examines a PDF object and optionally returns a modified object.

Method Detail

preFilter

PdfObject preFilter(PdfObject obj)
             throws PdfFormatException

Examines a PDF object and optionally returns a modified object. This method should return the original object or a modified replacement. If no modifications are desired, it should return the original object. This method may also return null in order to discard the object; however, this will cause postFilter(PdfObject) to be called with a null value as its parameter. A PdfArray or PdfDictionary object is considered to be a container, and this method filters the container as a whole before filtering each element within it (assuming the elements are still present in the modified object). When this method receives a container, that container's contents will not yet have been filtered by this method.

Parameters:

obj - the object to examine.

Returns:

the "filtered" object.

Throws:

PdfFormatException

postFilter

PdfObject postFilter(PdfObject obj)
              throws PdfFormatException

Examines a PDF object and optionally returns a modified object. This method should return the original object or a modified replacement. If no modifications are desired, it should return the original object. This method may also return null in order to discard the object. A PdfArray or PdfDictionary object is considered to be a container, and this method filters each element within it before filtering the container as a whole. When this method receives a container, that container's contents will have already been filtered by this method.

Parameters:

obj - the object to examine.

Returns:

the "filtered" object.

Throws:

PdfFormatException