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

[Heinrich Götzger <goetzger at gmx.net>]

On Sun, 20 Jan 2002, Heinrich Götzger wrote:

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

Where would one place a ClassLoader and all additionally stuff in our
packages hirarchy?

How about: org.xmlBlaster.util.loader (like tomcat does)
or just in org.xmlBlaster.util

regards


Heinrich


>
>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
>