How to wrap multiple paragraphs in one element?

Question

I'm creating a fairly complex PDF document in Java using iText 5. I add a bunch of Paragraph objects to my document. To improve readability of my code, I would like to create multiple methods to create different aspects of the document.

What type can I use to wrap multiple Paragraph objects in one unit, so I can return them from my sub-methods? The Element class does not have an add() method, nor does the Chunk class.

I tried Phrase, but then I lose all line breaks. Wrapping my Paragraph objects in another Paragraph object produces the desired output, but it feels odd, and I fear that the wrapping paragraph might introduce additional margins in the document.

So what is the best type for wrapping Paragraph objects in order to group them logically?

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Code example

My current code:

Document doc = new Document(...);
doc.add(new Paragraph("Aspect A.1"));
doc.add(new Paragraph("Aspect A.2"));
doc.add(new Paragraph("Aspect A.3"));

doc.add(new Paragraph("Aspect B.1"));
doc.add(new Paragraph("Aspect B.2"));

What I'm striving for:

Document doc = new Document(...);
doc.add(createAspectA());
doc.add(createAspectB());

// ...

private WrapperElement createAspectA() {
  WrapperElement wrapper = new WrapperElement(...);

  wrapper.add(new Paragraph("Aspect A.1"));
  wrapper.add(new Paragraph("Aspect A.2"));
  wrapper.add(new Paragraph("Aspect A.3"));

  return wrapper;
}

private WrapperElement createAspectB() {
  WrapperElement wrapper = new WrapperElement(...);

  wrapper.add(new Paragraph("Aspect B.1"));
  wrapper.add(new Paragraph("Aspect B.2"));

  return wrapper;
}

Answer 1

Wrapping my Paragraph objects in another Paragraph object produces the desired output, but it feels odd

While this indeed may feel odd, it does work and is a use case explicitly considered in the code. (For example look at the code of Paragraph.breakUp() and the inherited Phrase.process(ElementListener).)

and I fear that the wrapping paragraph might introduce additional margins in the document

It only does if you ask it to (using setIndentationLeft(float) / setIndentationRight(float) / setSpacingAfter(float) / setSpacingBefore(float)). Thus, you have the option to add extra indentation but you are not unwillingly subject to unwanted extra indentation.

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On the other hand, if you want to be 100% sure that there cannot be any unwanted influence, you can simply return an ordered Iterable<Element>, e.g. an ArrayList<Element>, and change the adding to the document to a forEach call:

private Iterable<Element> createAspectA() {
    ArrayList<Element> wrapper = new ArrayList<>();

    wrapper.add(new Paragraph("Aspect A.1"));
    wrapper.add(new Paragraph("Aspect A.2"));
    wrapper.add(new Paragraph("Aspect A.3"));

    return wrapper;
}

and replace

doc.add(createAspectA());

by

for (Element e : createAspectA())  doc.add(e);

(Unfortunately doc.add throws tagged exceptions, otherwise it could have been createAspectA().forEach(doc::add).)