----- Original Message ---- > From: Peter Firmstone <j...@zeus.net.au> > To: river-dev@incubator.apache.org > Sent: Sun, December 19, 2010 2:39:41 AM > Subject: Re: Fw: Re: Space/outrigger suggestions > > Ok thanks Nic, that's interesting, I stand corrected on erasure, seems > it's not entirely true. > > Any idea how we can enable runtime type checks for Generics? > > So far we can get the type information, I know it's preserved in > bytecode from my experience with ASM and adding Generics support to > classdep, however, how does it stop me from setting the field reference > to another Collection, containing Integers, at runtime, then returning > it to the space? > > Even with James' proposed javaspace method, which will work, the client > typecast is unchecked, it relies on the javaspace implementation to > return the correct type, which means you must trust the javaspace > implementation. > > This places a significant burden on the service implementor. > > What about Generics in other Service API? > > I use Generics for it's added type safety, but type safety doesn't > extend to distributed code, since it is a compiler check (hint: I'd love > to be pointed to a runtime type checker for Generics) I'd understand > the attraction of using Generic's if it was the case, but I'm failing to > understand the relevance of Generic's without type safety, could someone > please explain it for me? > > Or are we working on a tool to add type safety for Generic's to > distributed code? > > Sorry, the direction so far just appears to be, add Generics to > distributed code, without type safety checks, it seems type checks might > interfere with performance or something. >
To me this is not the concern of the impl. One should be using their own service API in these cases if they are using specific Enty class types. Now, in some purely dynamic system this may present a problem, but then again, that should be the concern of the implementer of the API which is using the spaces impl. For instance, if I'm writing a distributed application with a specific purpose, in most cases I can think of per domain concerns this is the case, I'm going to use a specific Entry type in the different distributed components, and thus the compiler will provide that safety for at runtime nothing will be accessing those Entries without knowing their specific types. I think this is something we should just warn about in documentation and explain the specifics; that is a lot to work around and possibly adding more overhead to the system. We should explain concerns from both views points: an unpredictable system capable of viewing and using types which are not known at compile time in the system components and where they are known. I believe most use cases are where they are known. Maybe I'm wrong. This is my own experience and point of view of course. Thanks, Wade ================== Wade Chandler Software Engineer and Developer NetBeans Dream Team Member and Contributor http://wiki.netbeans.org/wiki/view/NetBeansDreamTeam http://www.netbeans.org
