Re: [Rails-devel] Rails2.0: Portfolios, Ownable and Owner

[Stefan F. <ste...@we...>]

*** Further updates on Portfolios:

Considering Erik's feedback and some further considerations I have done 
the following changes to Portfolios / Ownable Items:

A) Ownable extends Comparable:
This implies that all ownable items have to define an ordering.
By default (in abstract OwnableItem) the ordering is based on their 
(unique) ids.

B) PortfolioSet is a SortedSet
Using the required ordering of ownable items, the portfolios are sorted 
accordingly.
(Accordingly PortfolioMap is a SortedMultimap).

Major advantage is that the ordering is always specified, and there is 
no ambiguity which certificate is returned, even if one asks only for a 
specified type.

*** Examples for orderings:

* PublicCertificates are sorted by
i) President or not
ii) CertificateType (and those are sorted by number of shares inside)
iii) CertificateId

This keeps the PresidentShare at position zero of each portfolio without 
requiring any code to keep it there. And it keeps the multi-shares at 
the top of a list of certificates.

* Trains are sorted by
i) TrainType
ii) TrainId

This makes it easy to generate the list of trains, as they are already 
sorted as required.