Optional really needs value types to be used more widely in these contexts. Given a language that doesn't have non-null baked into the type system or language, the next best thing would be a library solution. It's much better to indicate nullability in the parameter type rather than javadoc; the javadoc should still explain what a null value would imply for the method, but it's a poor substitute for encoding that fact.
Also, having consumeAValue vs consumeNoValue type of approach doesn't scale all that well with more than a single nullable parameter. Unfortunately, there's no good solution in java at the moment; before someone suggests using annotations, let me say they're helpful, but just a bandaid. On Fri, Oct 2, 2015 at 8:49 AM, Roger Riggs <roger.ri...@oracle.com> wrote: > +1 > > The "no such value" makes me curious about the context. > The @param tag really should be saying something about the parameter. > > The absence of an @throws (or class/package wide spec) documenting the NPE > for nulls > would indicate that null is allowed. > > Roger > > > > On 10/2/2015 4:10 AM, Remi Forax wrote: > >> Hi Max, >> yes, It's usually not a good idea, >> creating an Optional is like a boxing, you create an object (and prey >> that escape analysis will work), >> usually null means there is no value so either you have two methods >> consume, something like consumeAValue(String) and consumeNoValue() or you >> have one method consumeAValue and you don't call it if there is no value. >> >> regards, >> Rémi >> >> ----- Mail original ----- >> >>> De: "Wang Weijun" <weijun.w...@oracle.com> >>> À: core-libs-dev@openjdk.java.net >>> Envoyé: Vendredi 2 Octobre 2015 03:25:43 >>> Objet: Optional used as method argument? >>> >>> I hear people saying Optional is usually used as return values. Can I >>> use it >>> as an argument, like this? >>> >>> void consume(Optional<String> value) >>> >>> This way, I don't need to add spec like "@param value can be null if >>> there is >>> no such value". >>> >>> Thanks >>> Max >>> >>> >>> >
