CODEWITHSUNDEEP
java
user3478709
user3478709

Reputation: 943

How to use Java 8 optional API for method calls that return void

I am a newbie to Java 8 APIs. I have this piece of code, which needs to be optimized using Java Optional.

    if (Objects.nonNull(someDao.getById(id))) {
        someDao.delete(id);
    } else {
        throw new RuntimeException();
    }

I tried using Optional.ofNullable to optimize this piece of code.

    Optional.ofNullable(someDao.getById(id))
            .ifPresent(deleteObject)
            .orElseThrow(() -> new RuntimeException("some error message"));

    private Consumer<SomeObject> deleteObject = someObj-> {
          someDao.delete(someObj.getId());
    };

I am getting an error saying "can't invoke orElseThrow on primitive type void"

How can this be optimized to handle both data persistence and exception handling without using if-else blocks using Optional?

Upvotes: 0

Views: 1318

Answers (2)

Robin Topper
Robin Topper

Reputation: 2344

I think the if-statement you have is clear and don't see why you'd want to turn it in an Optional chain.

That being said, I also didn't manage to get it all done in one chain:

SomeObject someObj = Optional.ofNullable(someDao.getById(id))
.orElseThrow(() -> new RuntimeException("some error message"));
someDao.delete(someObj.getId());

.orElseThrow returns the value contained in the Optional if it is not null. So you can store it in a SomeObject and then delete it.

Upvotes: 0

Sweeper
Sweeper

Reputation: 273540

You need to do this in two separate calls:

Optional<SomeType> opt = Optional.ofNullable(someDao.getById(id));
opt.ifPresent(deleteObject);
opt.orElseThrow(() -> new RuntimeException("some error message"));

Upvotes: 1

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