How to check the field of an object on NPE and condition simultaneously through Optional? And if eve-CodePudding

I use Java 8 and have an issue with how to check objects through Optional. It should be like

Optional.ofNullable(person)
        .map(Person::getAge)
        .filter(age -> age > 25)
        .orElseThrow(new CustomException())

However, this code returns the value, but I don't need this. How fix it? Code should be like this

If (noNPE && person.getAge() > 25) {
       // do nothing
} else {
       throw new CustomException();
}

I don't need return value due to sonar throw warnings.

CodePudding user response：

The only thing that needs to be fixed in your code is the API usage, otherwise it won't compile:

Optional.ofNullable(person)
        .map(Person::getAge)
        .filter(age -> age > 25)
        .orElseThrow(CustomException::new);

(orElseThrow() needs to be fed with a Supplier)

There is no problem in ignoring the returned value.

Try @SuppressWarning("unused") or //NOSONAR to silence SonarQubes false positive.

CodePudding user response：

You could leverage ifPresent() as the predication in the if statement:

if Optional.ofNullable(person)
        .map(Person::getAge)
        .filter(age -> age > 25)
        .orElseThrow(new CustomException())
        .isPresent() {
       // do nothing
} else {
       throw new CustomException();
}