FUNCTION utilsPdfRemovePages(Options, InputPdfStream)
OUTPUT: ModifiedPdfStream, Attributes {originalPageCount, pagesRemoved}
// 1. Load PDF from InputPdfStream into an editable pdfDocument
Read InputPdfStream into memory
Load PDF data into pdfDocument object
originalCount = pdfDocument.getPageCount()
// 2. Decide removal strategy based on Options
IF Options say "Remove Blank Pages":
// Find and remove pages with no text, images, or annotations
Identify blank pages within pdfDocument
Remove all identified blank pages
ELSE:
// Keep only specified pages, remove others
Get list of PageNumbersToKeep from Options
Identify all pages NOT in PageNumbersToKeep
Remove identified pages from pdfDocument
END IF
// 3. Finalize and return
removedCount = originalCount - pdfDocument.getPageCount()
Save modified pdfDocument into outputBytes
Create ModifiedPdfStream from outputBytes
Create Attributes map {originalPageCount=originalCount, pagesRemoved=removedCount}
RETURN ModifiedPdfStream, Attributes
// Note: Includes error handling for invalid input and processing errors.
END FUNCTION
Methods used from the Apache PDFBox library
From org.apache.pdfbox.Loader:
loadPDF(byte[] pdfBytes): Loads a PDF document from a byte array.
From org.apache.pdfbox.pdmodel.PDDocument:
getNumberOfPages(): Gets the total number of pages in the document.
getPages(): Gets the page tree (PDPageTree) containing all pages.
getPage(int pageIndex): Gets a specific page by its 0-based index.
removePage(PDPage page): Removes the specified page object from the document.
save(OutputStream outputStream): Saves the document to an output stream.
close(): Closes the document and releases resources (implicitly called by the try-with-resources statement).
From org.apache.pdfbox.pdmodel.PDPage:
getResources(): Gets the resources dictionary (PDResources) associated with the page.
getAnnotations(): Gets a list (List<PDAnnotation>) of annotations on the page.
From org.apache.pdfbox.pdmodel.PDResources:
getXObjectNames(): Gets the names of external objects (like images) referenced in the resources.
From org.apache.pdfbox.pdmodel.common.PDPageable (Interface implemented by PDPageTree):
indexOf(PDPage page): Finds the 0-based index of a given page within the page tree.
From org.apache.pdfbox.text.PDFTextStripper:
PDFTextStripper(): Constructor to create a text stripper object.
setStartPage(int pageNum): Sets the 1-based page number where text extraction should start.
setEndPage(int pageNum): Sets the 1-based page number where text extraction should end.
getText(PDDocument document): Extracts text from the specified page range within the document.
