bean parser: support null values

[jknack]

Nullability across the framework is expressed using the java.util.Optional class. This is/was a right choice and let users to quickly identify where an optional value might occurs.

Suppose you have a form that will post a Book object with a title an optional releaseDate, you can express this like:

public class Book {
  public String title;
  public Optional<Date> releaseDate;
}

{
  post("/book", req -> {
   Book book = req.params(Book.class);
  });
}

This is nice, clean and add semantic to your business. Book is telling you that releaseDate might not be present.. which is very nice!

...Still, due that Optional was a recent addition to java... isn't widely used it by Java developers... So that is why we are going to support null values when user explicitly ask for it:

{
  // true means allowNulls
  parser(Parser.bean(true));

  post("/book", req -> {
   Book book = req.params(Book.class);
  });
}

So, now you can use `Date releaseDateinstead ofOptional releaseDate``

Source: https://groups.google.com/forum/#!topic/jooby-project/fyjwuXUxjfY
/cc @kshep92

[kshep92]

Awesome!