5 ms·

> If you used the returned Country to construct an API request including the name of the country, this will now produce strange countries named as “Optional[“No

• iainmerrick 7y ago
  The point is that if you change the type, existing calls to country.toString() will still compile. (Normally, fixing compile errors is a fairly reliable way to do this kind of refactoring.) That means you can’t guarantee to catch them all, so there’s a risk of modified behavior escaping into production.
• oftenwrong 7y ago
  As the sibling comment says, the post's advice is really about making your code refactoring-friendly with regard to type checking. You generally would not want to call '.get()' without an 'isPresent()' check because it will throw a NoSuchElementException if the Optional is empty. This is a foreseeable case, so most would like to handle it somewhat explicitly. Today, it is idiomatic to use '.map' to transform it: Optional<String> foo = optionalCountry.map(Country::getName); You can also throw a domain-specific exception from that point: Optional<String> foo = optionalCountry .map(Country::getName) .orElseThrow(...);
  • chopin 7y ago
    orElseThrow does return a String, not an Optional. You also could use orElse(null) or orElse("null") depending on the use case (eg. using as a part of toString).
    • oftenwrong 7y ago
      I'm useless without a compiler to check my types!