How to execute logic on Optional if not present?

Question

I want to replace the following code using java8 Optional:

public Obj getObjectFromDB() {     Obj obj = dao.find();     if (obj != null) {         obj.setAvailable(true);     } else {         logger.fatal("Object not available");     }      return obj; } 

The following pseudocode does not work as there is no orElseRun method, but anyways it illustrates my purpose:

public Optional<Obj> getObjectFromDB() {     Optional<Obj> obj = dao.find();     return obj.ifPresent(obj.setAvailable(true)).orElseRun(logger.fatal("Object not available")); } 

Answer 1

With Java 9 or higher, ifPresentOrElse is most likely what you want:

Optional<> opt = dao.find();  opt.ifPresentOrElse(obj -> obj.setAvailable(true),                     () -> logger.error("…")); 

Currying using vavr or alike might get even neater code, but I haven't tried yet.