Use Java Optional to refactor null check

byMR

June 8, 2023

What I am trying to achieve:

Use Java Optional to refactor null check.

Background:

I have a straightforward POJO class:

public record MyPojo(String someField, String someOtherField)

And this method:

    private static String question(final MyPojo mypojo) {
        if (null == mypojo) {
            return null;
        } else if (null == mypojo.someField()) {
            return null;
        } else {
            return mypojo.someField().toLowerCase();
        }
    }

Issue:

As you can see, while super easy to understand, this code is very verbose and lengthy.
MyPojo can be bull, and so can MyPojo.someField.
I need to check those two preconditions before applying my business logic (here lower case just for example)

Question:

Is there a smarter way, either using Optional, or something smarter, to refactor this?

>Solution :

You can chain your optional with .map() calls, the advantage of this approach is that it chains the operations together in a readable way and eliminates the need for explicit null checks:

private static String question(final MyPojo mypojo) {
    return Optional.ofNullable(mypojo)
              .map(MyPojo::someField)
              .map(String::toLowerCase)
              .orElse(null);
}