[Isolate-interest] CLDC compatiblity

[Sutanu Ghosh]

I think the goal to create a single unified api to
serve both JavaSE and JavaME/CLDC environments is not
a good idea. In trying to do so, it might limit the
full capability or future expansion of isolate spec in
JavaSE environment. Also, as already happened, the
java 5 language features were taken out from the api
in order to comply with JavaME.

I propose to make the JSR-121 api/spec targeted to
JavaSE platform only. A separate JSR can create the
JavaME/CLDC version of the isolate api. This has been
done for several other JavaSE packages in the past. 

Thanks,
-Sutanu


--- Jesper Zuschlag <jesper at zuschlag.dk> wrote:

> CLDC has been mention several times during this
> current public review  
> and I'm also of the opinion that multitasking
> capabilities is a very  
> important element in the future evolution of
> CLDC-based platforms  
> which makes CLDC-compatibility an important issue
> for JSR-121. I have  
> been talking with Pete Sober about this on several
> occasions and  
> apparently work has been done to make JSR-121 more
> compatible with  
> CLDC, however several stumbling-stones remains.
> 
> I have made a quick survey of the latest API
> proposal and come up  
> with a list of the issues I have found. The question
> is if these  
> issues should be handled by JSR-121 (possible as an
> amendment to the  
> JSR) or be postponed to a future JSR (e.g. next CLDC
> version).
> 
> Some issues could be easily solved:
> 
> On the issue of StreamBindings I agree with Bryn
> Rahm that using only  
> InputStream and OutputStream as source and
> destination for the  
> standard stream would make the design much cleaner
> (and make it  
> suitable for CLDC).
> 
> The use of Serializable on exceptions classes could
> be dropped in a  
> CLDC context similar to other exceptions in CLDC and
> MIDP.
> 
> So the remaining challenge is the whole area of
> security and context/ 
> properties, which heavily depends on the Java SE
> architecture and  
> thus cannot easily be applied to CLDC.
> 
> In my opinion, JSR-121 should include a base line
> semantic for  
> adapting JSR-121 into a CLDC environment that is
> compatible with the  
> current CLDC version, with the possibility for later
> versions of CLDC  
> to expand the semantic. E.g. the specification
> should state than in a  
> CLDC environment only classes from the same
> repository (jar file) as  
> the parent Isolate can be used as
> starting-point/main-class of a new  
> Isolate, and that Isolates always inherits
> permissions and properties  
> from the parent Isolate (although a mechanism
> allowing the parent  
> Isolate to add additional properties could perhaps
> be provided). Then  
> later version of e.g. CLDC could perhaps extend this
> semantic with  
> some kind of light-weight user-defined security
> mechanism.
> 
> By the way, is it the intent of the EG to write a
> "formal  
> specification" or is the JavaDoc  the chosen format?
> 
> /Jesper
> 
> 
> 
> Classe survey:
> 
> --------------------
> 
> ClosedLinkException:
> 
> -       Implements java.io.Serializable
> 
> Isolate
> 
> -       Applies java.util.Properties
> 
> -       Uses variable arguments in several methods
> (Isolate(..), start 
> (
)
> 
> IsolateException
> 
> -       Implements java.io.Serializable
> 
> IsolatePermission
> 
> -       Inheriting from
> java.security.BasicPermission
> 
> -       Incompatible security model. No extensible
> security model in  
> CLDC (sandbox confinement to originating jar-file,
> no class path)
> 
> -       Implements java.io.Serializable
> 
> -       Implements java.security.Guard
> 
> IsolateStartupException
> 
> -       Implements java.io.Serializable
> 
> IsolateStatus.ExitReason
> 
> -       Implements java.io.Serializable
> 
> IsolateStatus.State
> 
> -       Implements java.io.Serializable
> 
> LinkMessage
> 
> -       Applies java.net.ServerSocket
> 
> -       Applies java.net.Socket
> 
> StreamBindings
> 
> -       Applies java.io.FileOutputStream
> 
> -       Applies java.io.FileInputStream
> 
> -       Applies java.net.Socket
> 
> 
> 
> 
> 
>   > _______________________________________________
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>
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> 


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