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So i have a webapp that i am currently working on. it runs on java / MVC patter / MYsql/ scala / play framework.

i am looking to find a way to generate a pdf document using itext based on a report that is on the WEBAPP, so basically we will need to add a "Print button" on the report page, and extract the information to PDF.

thank you

AAFF
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1 Answers1

1

Without giving you actual code, I'm going to give you one approach on how you can do it.

If we assume you have some sort of structured data, like a list of items you want to print, you can use a visitor pattern.

What you want it to do is have one visit(...) method per type of item you want to print.

For example, if you had 2 classes: 

public class Foo {
    ...
    public int foo;
    ...
}

and 

public class Bar {
    ...
    public boolean bar;
    ...
}

then you could have your PDF visitor look something like this: 

public class MyPDFVisitor {
    ...
    public void visit(Foo foo) {
        ...
        // do something with foo.foo
        ...
    }

    public void visit(Bar bar) {
        ...
        // do something with Bar.bar
        ...
    }
}

Now, I see you want to use iText. So, what you could add to your MyPDFVisitor class to support that is something like this: 

public class MyPDFVisitor {
    public MyPDFVisitor() {
        this.document = new Document(PageSize.A4);
        this.outputStream = new ByteArrayOutputStream();

        try {
            this.pdfWriter = PdfWriter.getInstance(this.document, this.outputStream);
        } catch (DocumentException e) {
            e.printStackTrace();
        }

        this.document.open();
    }

    private void addDocumentName(String description) throws DocumentException {
        Paragraph preface = new Paragraph();
        preface.setAlignment(ElementTags.ALIGN_CENTER);
        addEmptyLine(preface, 1);
        preface.add(new Paragraph(new Chunk(description, getTitleFont())));
        addEmptyLine(preface, 2);
        document.add(preface);
    }

    private void addEmptyLine(Paragraph paragraph, int number) {
        for (int i = 0; i < number; i++) {
            paragraph.add(new Paragraph(" "));
        }
    }

    public void visit(Foo foo) {
        Integer fooValue = foo.foo;
        write(fooValue.toString(), Color.GREEN);
    }

    public void visit(Bar bar) {
        Boolean barValue = bar.bar;
        write(barValue.toString(), Color.RED);
    }

    public void write(String text, Color color) {
        // do the actual write to document here
    }

    public InputStream getInputStream() {
        try {
            // you can do some final actions here, before closing the writing to the document

            this.document.close();
        } catch (DocumentException e) {
            e.printStackTrace();
        }

        ByteArrayInputStream inputStream = new ByteArrayInputStream(outputStream.toByteArray());
        return inputStream;
    }

}

Please, don't confuse this for production code. I just gave you an example on how you can approach the problem and tackle it from there.

Disclaimer: Obviously, this is a Java solution, but the goal was to show you the concept, not give you the code you can copy/paste.

ioreskovic
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    There are many possible answers to the question, but the concept explained in this answer is certainly a valid one. Not the only one (and not 100% how I would do it), but worth looking at. – Bruno Lowagie Feb 12 '15 at 07:26
  • Now you had me intrigued! I haven't used iText for a long time now, but I'm interested in how the author of the library would tackle the solution :D – ioreskovic Feb 12 '15 at 07:33
  • Your approach is really good, but the devil is in the details. For instance: I would use a `Chunk.NEWLINE` to insert a new line. As for the architecture, I would first explore which of the following options are the best fit: http://stackoverflow.com/questions/26218444/generate-and-design-pdf-with-itextsharp-or-similar (of course: the question by @AAFF is too broad to make an accurate recommendation).Your suggestion is similar to my **Option 1** ;-) – Bruno Lowagie Feb 12 '15 at 07:36
  • Fair enough :D And that is really one great answer, I'll make sure I remember it for any future uses :D – ioreskovic Feb 12 '15 at 07:43