Avoiding Using .get and Optional.isPresent Options

Question

public ValueA map(ValueB valueB, Date date) { Optional<ValueC> valueCOpt = find(valueB); if (valueCOpt.isPresent()) { ValueC valueC = valueCOpt.get(); // call many getters on valueC and do a lot of logic with it. return map(/*some parameters*/); } return null; } 

That seems pretty ugly. The advantage of optionals has completely disappeared here. I read that it is better to use map or flatMap instead of get . But is it really useful if I replace each recipient, for example

 valueC.getFieldA() 

with

 valueCOpt.map(ValueC::getFieldA) 

Do you know some general or best practices here?

Answer 1

you can use

 public ValueA map(ValueB valueB, Date date) { return find(valueB) .map(valueC -> { // call many getters on valueC and do a lot of logic with it. return map(/*some parameters*/); }) .orElse(null); } 

The key point is that the matching function is evaluated only if the option is not empty, otherwise the result remains empty. orElse(null) will return null if optional is empty.

Answer 2

You need to match, then orElse () or orElseThrow () if you need an exception

 ValueA valueA = valueCOpt.map(valueC -> mapToValue(valueC)) .orElse(null); 

orElse () is used when you need a default value, in which case its null