I have a nullable object and I'm trying to throw an exception if the object is not null and does not meet a condition.
I try this way with Optional:
Optional.ofNullable(nullableObject)
.filter(object -> "A".equals(object.getStatus()))
.orElseThrow(() -> new BusinessUncheckedException("exception message"));
When the object is not null, it works as I want, but otherwise, it throws the exception too (and I don't want that).
There is a way to do that with Optional or other ways not using if object != null?
Assuming you aren't doing anything with the returned object, you could use ifPresent and pass a Consumer
nullableObject.ifPresent(obj -> {
if (!"A".equals(obj.getStatus())) {
throw new BusinessUncheckedException("exception message");
}
});
Note: As @Pshemo mentioned in the comments, the contract of the Consumer functional interface allows throwing only RuntimeExceptions.
Otherwise, you are better off with a if check as you've mentioned.
IMO, using a filter on Optional for checks like these is not that readable/intuitive. I would prefer,
if (obj != null && !"A".equals(obj.getStatus())) {
throw new BusinessUncheckedException("exception message");
}
If you map to null, the Optional becomes empty:
Optional.ofNullable(nullableObject)
.map(object -> "A".equals(object.getStatus()) ? object : null)
.ifPresent(object -> { throw new BusinessUncheckedException("exception message"); });