[PDFBOX-4738] getDocument().getObjects() returns nothing for split result documents

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.0.18
• Fix Version/s: 2.0.19, 3.0.0 PDFBox
• Component/s: Documentation
• Assignee: Tilman Hausherr
• Reporter: Yuguang Huang
• Created: 09/Jan/20 19:26
• Updated: 30/Jun/20 06:13
• Resolved: 01/Feb/20 12:32

Description

 

Hi PDFBOX community, we want to get objs count on pages instead of the whole document. 

Our way to do it is splitting the whole document into multiple documents containing only one page. But it seems then it returns documents/pages without objects, meaning getDocument().getObjects() returns an empty list. 

But if we save each page into bytes then load them into PDDocument, we are able to get the object counts. 

 

Is there any way we can get the page objs count without involving so much IO? Thanks! 

 

Output of the below code with a three-page PDF document:

 

Page objects count from splitted pages:
page [1] num of objs [0]
page [2] num of objs [0]
page [3] num of objs [0]
Page objects count from pages generated from bytes:
page [1] num of objs [20]
page [2] num of objs [51]
page [3] num of objs [20]

 

private static void printNumObjects(String pdfFilename) throws IOException {
 byte[] fileContent = Files.readAllBytes((new File(pdfFilename)).toPath());
 PDDocument document = PDDocument.load(fileContent);
 List<PDDocument> pages = new Splitter().split(document);
 List<byte[]> pageBytes = pages.stream().map(page -> {
 try (ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
 page.save(baos);
 page.close();
 return baos.toByteArray();
 } catch (IOException e) {
 LOG.error("Failed to get bytes from page.", e);
 return new byte[0];
 }
 }).collect(Collectors.toList());

 System.out.println("Page objects count from splitted pages:");
 IntStream.range(0, pages.size()).forEach(i -> System.out.println(String.format("page [%d] num of objs [%d]", i + 1, pages.get(i).getDocument().getObjects().size())));

 System.out.println("Page objects count from pages generated from bytes:");
 IntStream.range(0, pageBytes.size()).forEach(i -> {
 try {
 System.out.println(String.format("page [%d] num of objs [%d]", i + 1, PDDocument.load(pageBytes.get(i)).getDocument().getObjects().size()));
 } catch (IOException e) {
 LOG.error("Failed to load page.", e);
 }
 });
}