[Springframework-developer] RFE: Multiple parents for ApplicationContext

[Roland H. <Rol...@co...>]

Hi,

we are using multiple application modules, which we are wiring together during a bootstrap 
process. Each module has it's own container which is connected to its dependent module via 
a parent-child relationship (as described in 
http://static.springframework.org/spring/docs/1.2.x/api/org/springframework/beans/factory/access/SingletonBeanFactoryLocator.html)

However, the restriction to a strict treelike organization of ApplicationContext limits 
the usability of this pattern.

E.g. imagine the following use case with four contexts:

   * bootstrap-ctx.xml for defining base beans used by any other container
   * dao-ctx.xml for defining DAOs. Depends on bootstrap-ctx.xml
   * security-ctx.xml depends also on bootstrap-ctx.xml but not on
     dao-ctx.xml
   * service-ctx.xml which depends on beans defined in security-ctx.xml and dao-ctx.xml.

Using an hierarchical container setup something like a 'diamond' (graph) would be appropriate:

                            bootstrap
                              /   \
                             /     \
                           dao    security
                             \     /
                              \   /
                             service

However, Spring doesn't allow multiple parent container, so we are left with the following 
linear setup:

                             bootstrap
                                 |
                                dao
                                 |
                              security
                                 |
                              service

which has the undesired side-effect, that 'security' has access to 'dao'. Ok, this works 
for this simple setup, but one can easily imagine situations, where this 'linearity' 
restriction bites much harder.

My question is, whether there are any plans for supporting ApplicationContext chaining in 
a more flexible way (i.e. with multiple parents) ?

Or is there already another support for scoping beans coming from various application 
components ?

For the moment, we switched to a single, big container which import various context 
snippets from the application modules and use bean-aliasing for scoping.

ciao...
-- 
                                          ...roland huss
                                               consol.de