Using Single Template for all PDF Pages in IText 7

I have the following PDF template which should be consistent for all the pages that gets added in the PDF I am creating ,

The issue is that, am getting this template only for Page 1 and for rest of the pages only blank template is used , Here’s the code am using right now,

PdfDocument pdfDoc = new PdfDocument(new PdfReader(SRC),new PdfWriter(baosPDF));

PageSize ps = new PageSize(900, 780);

// Initialize document
Document document = new Document(pdfDoc, ps);
document.setMargins(80f, 20f, 50f, 20f);

PdfFont font = PdfFontFactory.createFont(StandardFonts.HELVETICA);
PdfFont bold = PdfFontFactory.createFont(StandardFonts.HELVETICA_BOLD);
for(int i = 0; i < 10; i++){
    document.add(new Paragraph("Some Content"));
    document.add(new AreaBreak(AreaBreakType.NEXT_PAGE));
}
document.close();

I have referred this itextsharp add 1 page template to all pages example already , but I need something specific to Itext 7 since it varies a lot from 5.x.x versions

how do I get my PDF to have the single template as shown in image to be common for all the pages ?

Answer

As explained in the comments, you need to create an IEventHandler as described in chapter 7 of the tutorial

This is an example from the PDF to HTML tutorial (chapter 4).

class Background implements IEventHandler {
    PdfXObject stationery;

    public Background(PdfDocument pdf, String src) throws IOException {
        PdfDocument template = new PdfDocument(new PdfReader(src));
        PdfPage page = template.getPage(1);
        stationery = page.copyAsFormXObject(pdf);
        template.close();
    }

    @Override
    public void handleEvent(Event event) {
        PdfDocumentEvent docEvent = (PdfDocumentEvent) event;
        PdfDocument pdf = docEvent.getDocument();
        PdfPage page = docEvent.getPage();
        PdfCanvas pdfCanvas = new PdfCanvas(
            page.newContentStreamBefore(), page.getResources(), pdf);
        pdfCanvas.addXObject(stationery, 0, 0);
        Rectangle rect = new Rectangle(36, 32, 36, 64);
        Canvas canvas = new Canvas(pdfCanvas, pdf, rect);
        canvas.add(
            new Paragraph(String.valueOf(pdf.getNumberOfPages()))
                .setFontSize(48).setFontColor(Color.WHITE));
        canvas.close();
    }
}

As you can see, we read the template in the constructor, and we draw it to the Canvas in the handleEvent() method. In this example, we also add a page number in white, you can remove all those lines.

public void handleEvent(Event event) {
    PdfDocumentEvent docEvent = (PdfDocumentEvent) event;
    PdfDocument pdf = docEvent.getDocument();
    PdfPage page = docEvent.getPage();
    PdfCanvas pdfCanvas = new PdfCanvas(
        page.newContentStreamBefore(), page.getResources(), pdf);
    pdfCanvas.addXObject(stationery, 0, 0);
}

Obviously, you also need to declare the handler:

PdfDocument pdf = new PdfDocument(writer);
IEventHandler handler = new Background(pdf, stationery);
pdf.addEventHandler(PdfDocumentEvent.START_PAGE, handler);