Question on sharing a JVM between 'applications'...

[Steve Wampler]

I'm looking into using a 'Container/component model' (using ICE,
not CORBA, in this case). The general idea is that a container
can manage multiple, independent applications (components).

However, I'm stuck on one point. When running an application
on a standalone JVM, it's possible share data across all objects
through the use of a singleton class, or through static variables
and methods. However, that breaks down when sharing a JVM
across applications. As far as I know, that singleton class
(applies to static variables, as well) would be visible to all
components in the JVM - instead of just to that single component).

I need 'component level locally-global' storage. Is there a
way to get this other than having to pass some id data through
*every* method and constructor call performed in the component
[which is not an acceptable solution]?

Anyone run into this and have a solution (be careful if you
haven't thought about it before - I don't think the solution
is obvious...)

Thanks!
Steve

 

[Lee Fesperman]

I'm looking into using a 'Container/component model' (using ICE,
not CORBA, in this case). The general idea is that a container
can manage multiple, independent applications (components).

However, I'm stuck on one point. When running an application
on a standalone JVM, it's possible share data across all objects
through the use of a singleton class, or through static variables
and methods. However, that breaks down when sharing a JVM
across applications. As far as I know, that singleton class
(applies to static variables, as well) would be visible to all
components in the JVM - instead of just to that single component).

I need 'component level locally-global' storage. Is there a
way to get this other than having to pass some id data through
*every* method and constructor call performed in the component
[which is not an acceptable solution]?

This is solved by using a separate classloader for each component ... that's what
containers like application servers do.

Anyone run into this and have a solution (be careful if you
haven't thought about it before - I don't think the solution
is obvious...)

There are still other issues to be dealt with for true isolation of components --
System.out/System.in/System.err for instance, however the classloader solution may be
acceptable isolation for simple situations.

 

[Steve Wampler]

This is solved by using a separate classloader for each
component ... that's what containers like application servers do.


There are still other issues to be dealt with for true isolation
of components -- System.out/System.in/System.err for instance,
however the classloader solution may be acceptable isolation
for simple situations.

Yes - that should work for my purposes just fine. Thanks!