The Java Memory Model & Concurrency

I just watched the presentation Advanced Topics in Programming Languages: The Java Memory Model given by Jeremy Manson (Google Tech Talks March 21, 2007). Although I was familiar with most, I really enjoyed watching the complete video (I rarely do this for those longer than 15min). If didn't see it already:

Extended Type-Cast vs. Closures vs. Current Java

Although I'm not a fan of messing up the Java language, I had another idea, I'd like to share:

An extended type-cast for single-method interfaces, which succeeds if the signatures are compitable. More precise, the target's method could be overridden by the one of the source interface, the syntax could be: (A as B)
(Note: contravariant arguments would be also possible)

I guess it's is highly related to the ongoing debate if and how to integrate closures (CICE, FCM and BGGA). Although, I think the last one has its pros and I really like the idea of first-class methods (place my vote here), the remaining one really has a mighty ally: simplicity.

However, the absense of method/functions type, which can be assigned only depending on their signature types, makes it look a bit clumsy. With the proposed extended type-cast, things would be more balanced as this example shows.



Just, for those who didn't have noticed yet, the main thing is (Bar as Foo), but it looks nicer within the other syntax sugar as well:

• calling the single method of an interface, its name can be omitted
• simplifyedcreation of anonymous classes, which implement single-method interfaces
• usage of var/final instead of specifying the reference type

EDIT: Modified the source to match the BGGA proposal accoringly to Neal Gafter's comment.