(invalid) dependencies management

hi all,
  I have a (two-fold) question about object dependencies when a particular object is recompiled:    

1. a query can be run pre and post object compilation to determine the objects that got invalidated by that specific object's compilation (or object ddl change) by looking at the (ALL_)OBJECTS STATUS column and taking appropriate data as such.
2. another method would be to investigate the (ALL_)SOURCE [where upper(text) like upper('%xxx') and name<>'xxx'] to determine first level dependencies. I'd like to create a query that determines the entire dependency chain of objects that will get invalidated... probably something using CONNECT BY for recursive querying, keping in mind that, I believe, there needs to be an specific compilation order ;-) [unless there are other simpler query/tricks that I don't know of]

  Could someone help w/ the latter strategy?   thx anticipatedly,
  Cos            

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