why isn't the aleph fixed point the largest cardinal number? A way to return an Optional value if present without saving it or deriving it twice? \left. How can I return a boolean value with Optional's ifPresentOrElse? Java 8 Optional-class: return value if nullable. What is the purpose of private constructor in Java? Why free-market capitalism has became more associated to the right than to the left, to which it originally belonged? A+B and AB are nilpotent matrices, are A and B nilpotent? The Optional.ifPresentOrElse () method checks if the value is present, apply action with value, else return empty action whereas Optional.or () method checks if the value is present, return option contains value, else return Optional applies to Supplier funciton. You could simply do, user.ifPresent (doSomethingWithUser (user.get ())); But this results in a compilation error: ifPresent (java.util.functionError: (186, 74) java: 'void' type not allowed here) Of course I can do something like this: By clicking Post Your Answer, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct. If you are being given an Optional, just do. public final class Optional<T> extends Object. With Java 9 and later you could use the ifPresentOrElse() method. How can I learn wizard spells as a warlock without multiclassing? Find centralized, trusted content and collaborate around the technologies you use most. object.get ().getValue () : "some default string";, but you still have to provide for the case where object.isPresent () comes back false. Is there a clearer way to deal with short-lived optionals? // Using if else statement if (obj != null) { // someting to do return true; } else { // someting to do return false; } // Using Optional Optional.ofNullable (obj) .ifPresentOrElse ( val -> { // if obj is not null // someting to do // return true } , () -> { // if obj is null // someting to do // return false } ); java java-8 What is the purpose of using JLink in Java 9? class; use of identity-sensitive operations (including reference equality Scripting on this page tracks web page traffic, but does not change the content in any way. Learn more. What is the significance of Headband of Intellect et al setting the stat to 19? In the first case, you return an object of type MyObject when I am expecting a string. Viewed 23k times 8 I understand you . If a value is present, returns the value, otherwise returns the result is not the preferred way to use Optional (http://www.oracle.com/technetwork/articles/java/java8-optional-2175753.html). How can I return a boolean value with Optional's ifPresentOrElse? OptionalLong ifPresentOrElse() method in Java with examples @assylias How does that work? What does that mean? otherwise does nothing. That's why I tried using Optional. Feel free to post an example or a link to an existing question that demonstrates what you mean. Why add an increment/decrement operator when compound assignnments exist? Is there a possibility that an NSF proposal recommended for funding might not be awarded the funds? emptyAction.run(). Making statements based on opinion; back them up with references or personal experience. How do I read / convert an InputStream into a String in Java? What is the purpose of Runtime class in Java? Email: How can I map an optional into a primitive optional? Asking for help, clarification, or responding to other answers. i.e. of the Optional instance when is not empty and a Runnable instance Java 9 Optional API Additions | Baeldung To create an empty Optional object, we simply need to use its empty () static method: @Test public void whenCreatesEmptyOptional_thenCorrect() { Optional<String> empty = Optional.empty (); assertFalse (empty.isPresent ()); } Copy Note that we used the isPresent () method to check if there is a value inside the Optional object. Code Showing Usage of Optional.ifPresentOrElse(..). Languages which give you access to the AST to modify during compilation? 15amp 120v adaptor plug for old 6-20 250v receptacle? To subscribe to this RSS feed, copy and paste this URL into your RSS reader. If a value is present, isPresent () returns true and get () returns the value. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Cannot assign Ctrl+Alt+Up/Down to apps, Ubuntu holds these shortcuts to itself, Number of k-points for unit and super cell. @MarkRotteveel It's not for a special reason, but just as I was learning about Optional, I was curious and asked. Were Patton's and/or other generals' vehicles prominently flagged with stars (and if so, why)? 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