Re: [xmlblaster-devel] XML-CORBA mix - Classloader approach

[Heinrich Götzger <goetzger at gmx.net>]

Hi,

I like this idea, it sounds good to me and addresses many problems which
we have discused, and still do.

Go for it!

On Sun, 20 Jan 2002, Marcel Ruff wrote:

>Hi,
>
>on the tomcat page
>   http://jakarta.apache.org/tomcat/tomcat-4.0-doc/class-loader-howto.html
>
>there is a nice overview about classloader issues.
>
>
>Probably xmlBlaster should use a customized classloader hierarchy
>as well to avoid jar conflicts.
>
>Currently i know of following conflicts in xmlBlaster:
>
>  - xml parser incompatibility
>  - multiple CORBA implementations
>  - java_cup conflict for JDBC-tinySQL and JacORB-idl
>
>
>What about this classloader hierarchy:
>======================================
>
>       Bootstrap
>
>           |
>
>        System
>
>           |
>
>        Common
>
>       /          \
>
>  xmlBlasterCore   Shared
>
>                 /     \  \
>
>           PluginX  PluginY PluginZ ...
>
>Where "Plugin*" are all xmlBlaster plugins, like
>security plugins, protocol plugins, persistence plugins
>and other future plugin interfaces.
>
>The xmlBlaster plugin loader diverges from the default Java 2 delegation
>model. When a request to load a plugin is processed, this class loader
>will look in the local repositories first, instead of delegating before
>looking. All other class loaders follow the usual delegation pattern
>(looking for the class in the parent classloader first).
>(Possibly xmlBlasterCore should look local first as well).
>
>Specialized jar files (if needed) will reside in subdirectories of
>    xmlBlaster/lib
>representing the package part below org.xmlBlaster.
>Example:
>
>    xmlBlaster/lib/protocol/corba
>                           /xmlrpc
>                  /authentication/plugins/ldap
>                                         /htpasswd
>                  /persistence/xmldb/xindice/
>    ...
>
>
>Now we need:
>
>- Comments on this.
>- A volunteer having the time to code it.
>

best regards,

Heinrich
--
http://www.xmlBlaster.org