Sebastien, I think we could implement the following classloading changes to Tuscany (in this order). I will post a more detailed proposal (along with some questions) based on the feedback.
1. Application classloading - move from a single thread context based classloader to OSGi-style multiple-classloader framework 2. Tuscany runtime classloading framework - enable the use of multiple classloaders, with an API in host-embedded or the new domain APIs to specify multiple runtime/extension classloaders 3. Reimplement Tuscany runtime extension mechanism so that SPI classloader does not require visibility of extension modules. 4. Remove the use of thread context classloader inside Tuscany - use specific classloaders based on what is being loaded. Thread context classloader will be the parent of all classloaders used in Tuscany to enable applications as well as 3rd party code to continue to use it. 5. Enable extensions to be packaged as separate OSGi bundles with separate classloaders, but with OSGi-defined package dependencies across extension modules. Default classloading for Tuscany runtime+extensions (CLASSPATH based single Java application classloader) will continue to be used for all existing tests and samples, but new tests will be added to test classloader-based isolation. Thank you... Regards, Rajini On 10/19/07, Jean-Sebastien Delfino <[EMAIL PROTECTED]> wrote: > > I wanted to summarize this thread as it has been pretty popular - I > guess we all know what a classloader is and are happy to talk about it > :) - but I am getting lost in the various exchanges. > > Could anybody please help provide 2 or 3 short sentences summarizing the > first 2 or 3 steps that are going to be implemented? > > Thanks... > > Simon Laws wrote: > > On 10/18/07, Mike Edwards <[EMAIL PROTECTED]> wrote: > > > >> Folks, > >> > >> Comments inline > >> > >> Simon Laws wrote: > >> > >>> Hi Rajini > >>> > >>> Re. 4 on Simon's list. Maybe it is useful to more clearly distinguish > >>> between those Tuscany modules that are expect to be loaded statically, > >>> assembly, core, etc and those that expected to be loaded dynamically, > >>> binding.?, implementation.? etc. I find the term "module" a little > >>> unsatisfactory. Raymond, in his diagram, used Tuscany core and Tuscany > >>> extension and in a previous post used Tuscany runtime and Tuscany > >>> extension. I prefer the latter pair just because we have a maven > module > >>> called core. > >>> > >> +1 > >> > >> > >>> This leads to a 4a and 4b based on Raymond's post/diagram > >>> > >>> 4a Tuscany extension module code shouldn't be able to see other > >>> > >> extension > >> > >>> modules (not sure what the dotted line on the diagram implies but I > >>> > >> expect > >> > >>> that it's to do with modules like binding-ws-axis2 and binding-ws > >>> interacting) or application code or Tuscany runtime code other than > via > >>> > >> the > >> > >>> SPI. > >>> > >> Hmm, first, this ain't the case today and it will need some thought. > >> > >> The "Java" extensions do share code and it would be crazy for them not > >> to share the code. So, Spring uses stuff out of the base Java > extension > >> - and I am sure that other "Java" type extensions would want to do the > >> same. > >> > >> In an OSGi world, it would be fine to express the dependency in a > simple > >> way. For non-OSGi I'm not sure of the best route. > >> > >> I suspect that other extension types may want to share stuff as well. > >> > > > > > > Agreed. Hence I pointed out the relationship between binding-ws-axis2 > and > > binding-ws. There are loose groups of software spread across multiple > maven > > modules that just represent modularization of the software for clarity > and > > reuse purposes. Then there are the modules that are intended to be > loaded as > > extensions. Not all maven modules are create equal :-) The non OSGi > world is > > managed by the dependencies that appear in out maven pom files. Without > this > > dependency tree you just have to know that, for example, binding-ws has > to > > be on the classpath when you also include binding-ws-xml which is in > turn a > > dependency of binding-ws-axis2. Nothing too unusual there until you > start > > talking about having separate class loaders for each extension as has > been > > discussed previously in this thread. You really need to understand what > an > > extension is, i.e. it is unlikely to be a single maven module. > > > > > > > >> 4b Tuscany runtime code shouldn't be able to see Tuscany extension code > or > >> > >>> application code. > >>> > >> That sounds a bit odd. Perhaps I've not got the right end of the > stick, > >> but the some code - either core and or extensions has to get very > >> intimate with the application code. Introspection, instantiation, > >> injection - all has to be done either by core code or extension code. > >> > >> Perhaps I've not understood the separation you're looking for? > >> > > > > > > This should say "shouldn't be able to statically see..". I had imagined > that > > these are all of the implementation modules that sit behind the SPI > > > > > >>> Then, from reading your comments, we have to be clearer about what the > >>> > >> SPI > >> > >>> is providing an interface to because it current includes interfaces to > >>> > >> the > >> > >>> underlying runtime modules but also the host-embedded classes which > >>> > >> strike > >> > >>> me as being more API than SPI. We are reorganizing the domain/node > >>> interfaces at the moment so hopefully we can clear this last point up > as > >>> part of that. > >>> > >>> Regards > >>> > >>> Simon > >>> > >>> > >> --------------------------------------------------------------------- > >> To unsubscribe, e-mail: [EMAIL PROTECTED] > >> For additional commands, e-mail: [EMAIL PROTECTED] > >> > >> > >> > > > > > > > -- > Jean-Sebastien > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > >
