[QUANTITY] and [OBSERVATION] data models: mutability

[Martin Hill]

David Berry wrote:

> That's certainly a possibility. It would be particularly relevant I guess
> for multi-threaded access to the Quantity. But on the other side of the
> balance is the expense of object creation in most OO languages.

It applies not just to multi-threaded access, but any occasion where 
more than one reference is held (I'm in a bit of a rush just now but can 
do examples for next week if need be).  The object creation overhead is 
a red herring at this stage!  It only really matters in tight, large 
loops where Quantity is likely to be inappropriately heavyweight anyway.

Cheers,

Martin


-- 
Martin Hill
www.mchill.net
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