using jcr mapping for Document Management System

[ruchi goel]

Hi,
  I am trying to design Document Management System using JSR170 
impl(Jackrabbit).
Checked out graffito framework but it has its own complex layers for  
persistence  conversion, versioning, locking.

JSR170 impl already provides implementation for versioning, locking etc. 
I found jcrmapping layer very useful for persistence , services and 
mapping java objects to nodetypes.

Few questions :

1. Is it a good idea to use only jcr mapping layer and design a Document 
Management System .? Depend on JSR170 impl for versioning, locking etc.

2. Checked out the model for  CmsObject,Document,Folder and their 
corresponding mapping files in test code . These seem to inherit from  
nt:base and then all basic properties fr files/folders seem to havebeen 
custom defined. Why can't we use nt:folder as supertype for 
graffito:folder and nt:file as supertype for graffito:document  and 
inherit the properties as it is , instead of defining them in mapping files.


Thanks,
Ruchi