Preparing for the 0.2 draft

[Alex Blewitt]

If we admit certain classes of (ahem) classes for SAM then should  
there be a diffrenve between those with final vs non-final fields?

One common (stats awaiting) pattern I've seen is to have a SAM class  
to calculate a running total of e.g. sum of a list.

public abstract class Fold {
   private int start;
   public abstract int op(int, int);
}

list.apply(r = #int(int a, int b) { return a+b; })
r.getTotal()


Sent from my (new) iPhone

On 29 Jan 2010, at 08:56, Alex Buckley <Alex.Buckley at Sun.COM> wrote:

> Many thanks for everyone's comments on the 0.1 draft. The "foo.()"
> invocation syntax looks like a winner, and I am seriously considering
> rearranging the function type syntax to have argument types first.
> Requiring a lambda expression to denote its return type is also
> increasingly appealing. SAM classes are staying for now.
>
> The discussion of transparent 'this' v. non-transparent 'this' comes
> down to the question of what a lambda in Java is for. (Zdenek Tronicek
> ably made this point earlier.) Part of the answer lies in  
> understanding
> when to use an anonymous inner class and when to use a lambda
> expression. A step towards that understanding would be knowing how
> anonymous inner classes are used today.
>
> It would be very interesting if list members could provide the  
> following
> statistics for codebases with which they are familiar:
>
> - What %age of anonymous inner classes declare a single non-Object  
> method?
> - What %age of single-method anonymous inner classes declare fields?
> - What %age of single methods in anonymous inner classes use 'this'?
> - What %age of single methods in anonymous inner classes recurse?
> - Are the %ages different for anonymous inner classes that implement  
> an
> interface v. that extend a class ?
>
> (As well as anonymous inner classes, any utility class that
> implements/extends a SAM type is of interest, such as this nested  
> class
> from the extra166y.ParallelArray Javadoc:
>   static final class IsSenior implements Predicate<Student> {
>      public boolean op(Student s) { return s.credits > 90; }
>    }
> )
>
> Alex
>