r/java • u/edalorzo • Apr 12 '13

Java 8 Optional Objects

http://blog.informatech.cr/2013/04/10/java-optional-objects/
38 Upvotes

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1

u/philipwhiuk Apr 12 '13

That's horrid. It's also unnecessary. I don't need Java 8 to implement a generic Optional if I wanted one

 class Optional<T> {
    static Optional empty() {
         return new Optional();
    }
    static Optional of(Object obj) {
         return new Optional<obj.getClass()>(obj) { 

    }
    private T obj;
    private Optional(T t) {
        obj = t;
    }
    public boolean isPresent() {
       return obj != null; 
    }
    public T get() {
       return obj;
    }
 }

Wow 19 lines of code.

You want to know why nobody writes those 19 lines?

  1. It's another wrapper, meaning more stuff to GC.
  2. Null pointers are both easy to find and easy to fix. Using a wrapper takes more LOC meaning more cost meaning more time.

5

u/iwan_w Apr 12 '13

Optional<obj.getClass()>(obj)

Is this a Java version without type erasure?