Re: Joe-E

On 04/29/2010 11:42 AM, David Wagner wrote:
> Steven R. Brandt wrote:
>    
>> After a little thought, I believe I have an acceptable solution for the
>> problem. In case it is of use, here's what I did to implement a
>> powerless list class:
>>
>> public class PowerlessList<T>  {
>>      
> Did you mean to add "implements Powerless"?
>
> Why not use org.joe_e.array.PowerlessArray?  If you want an ordered
>    
No, the point was that I wanted the ability to use String, and
String (while powerless) does not implement Powerless and
the code won't compile.
> sequence of Powerless items, it seems to be exactly what you want:
> PowerlessArray is a Powerless, ordered sequence of Powerless items.  As a
> bonus, it provides more efficient random access to elements than your
> PowerlessList, and the PowerlessArray has a number of utility methods.
>    
But I can't add to it in a convenient way. A powerless linked list is 
very useful, it
is arguably the of the main data structure of Haskell (and with Joe-E
you are sort of turning Java into a functional language).
> And, most importantly, PowerlessArray cleanly handles the issue you
> mentioned (it can hold classes explicitly declared Powerless; it can
> also handle legacy classes that are honorarily Powerless, like String).
>
>    
>> The key is the holder class. It is able to hold a String, Integer, etc.
>> Essentially, it turns the check from a compile-time to a run-time check,
>> and allows me to use either String or Powerless. Of course, the whole
>> thing might die with a bad type error, so it's a trade-off.
>>      
> I noticed your implementation hardcodes String, Number, Boolean, and
> Character, so it may miss other classes that are honorarily powerless.
>
>    
Sure, and these would have to be added by hand.
> Should we add an ImmutableHolder and a PowerlessHolder to the Joe-E
> library, written along the lines of the ImmutableArray and PowerlessArray
> implementation?  If so, do you want to propose some code?
>
>    
That would be nice! My Holder class was in the email.
>> The basic problem, I think, is that Powerless is a marker interface. If
>> it were an attribute instead, then I think things would be nicer.
>>      
> Hmm.  I haven't thought about this, but I'm guessing one challenge
> is that this would require re-implementing Java's type checks, so it
> might take more work.
>
>    
It would definitely be tricky to get working, but I think it would
be worthwhile.
>> Maybe you could consider this for a future version?
>>      
> Unfortunately we have no current plans, and no resources, to make major
> changes to Joe-E.  We're not actively developing Joe-E at this point;
> it's a research project, and we've currently moved on to other projects.
>    
Understood. We intend to use Joe-E to implement a website for
managing accounts and allocations on supercomputers. We like
the security properties and hope to get a conference paper or
two out of the project.

Maybe if that gains some recognition, it might lead to more development
for Joe-E. Who knows?

I like the framework and would like to see more done with it.

Cheers,
Steve