Ah,
 Yes now I understand.  This is handled by ODBMS products, I know
Objectivity supports this,
 but I'm not sure I've seen any O/R tool support polymorphic collections.
  There has been some talk about it on this list before.  Thanks for
clarifying.

-Daniel



-----Original Message-----
From: Charles Forsythe [mailto:forsythe@;alum.mit.edu]
Sent: Wednesday, October 23, 2002 7:00 PM
To: [EMAIL PROTECTED]
Subject: Re: [castor-dev] Composite pattern


Daniel Honig wrote:

> The composite pattern describes objects that contain collections of
> objects?
>
> Isn't this simply a 1..N relationship?......For example a book has
> 1..N pages?....

Yes, but what if those pages are of different subclasses?  With Castor
JDO, the 1..N has to be a homogenous collection of the same class type.
 Composite pattern allows you to have different classes in the the 1..N
relationship.

Castor doesn't handle this.

-- Charles

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