Multi tool use

Clash Royale CLAN TAG

Return null or new object using Optional object fields

We have a method, wherein we receive an Optional<SomeType> object. If the contained SomeType object is not null then we have to initialize a SomeOtherType object using the fields of the SomeType object and return that new object; otherwise we have to return null

Optional<SomeType>

SomeType

SomeOtherType

SomeType

We found multiple different solutions where we perform this task with two statements, first retrieving the optional object and then second creating the other type object e.g.

private SomeOtherType ourMethod() {
SomeType someObject = getOptionalSomeTypeFromSomeWhere().orElse(null);
return someObject != null ? new SomeOtherType(someObject.getField1(), someObject.getField2(), ...) : null;
}


Is it possible to cover this with one statement? So far we could not figure to do the null checks, accessing the fields, new object creation etc. all in one

Basically a more complex case of this question: Get field of optional object or return null

Optional

null

Optional

Optional<SomeType>

1 Answer
1

Use Optional.map:

Optional.map

return getOptionalSomeTypeFromSomeWhere()
.map(someObject -> new SomeOtherType(someObject.getField1(), someObject.getField2(), ...)
.orElse(null);


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