在这种情况下如何使用Guava Optional

Question

I have a scenario which I want to use Guava Optional, but there is problem:

The method is like this:

private static void method(Optional<Object> myOptional) {
   if(myOptional.isPresent()) {
       ....
   }
}

The myOptional can contain non-null value, null value, or absent(). A null is a valid input in this scenario.

In the method, I want to process non-null value and null value using differnt ways, but ignore absent value.

However, if I use isPresent here, the null value will be ignored as well. But if I use "get" method, the absent value will throw exception. If I use orNull, the absent value also returns as null.

I am not sure what I shall do here. But I think the reason to create Optional is to differentiate null and absent so that null becomes a valid meaningful value. But it looks like there is no method in Optional that allows me to achieve my usecase.

Can anyone help? Thanks.

Answer 1

You can't do that.

The javadoc says it explicitly: an Optional may contain a non null reference . Never a null one.

What you can do is create an Optional.fromNullable(whatever).orNull() . But an Optional will never differentiate a null value from absent, since it is not what it is meant to do!