Java 8: java.util.Optional
private abstract Optional<String> methodThatReturnsOptionalString();
private void useOptionalString() {
Optional<String> myOptionalString = methodThatReturnsOptionalString();
if (myOptionalString.isPresent()) {
String myUnboxedString = myOptionalString.get();
System.out.format("Optional string had value: %s\n", myUnboxedString);
} else {
System.out.println("Optional string was empty");
}
}
Swift Optional
func methodThatReturnsOptionalString() -> String? {
return (arc4random() % 2 == 0) ? nil : "Hello world"
}
func useOptionalString() {
var myOptionalString = methodThatReturnsOptionalString()
if let myUnboxedString = myOptionalString {
println("Optional string had value \(myUnboxedString)")
} else {
println("Optional string was empty")
}
}