Re: [Geotools-devel] Learning about being greedy

[Martin D. <mar...@ge...>]

Andrea Aime a écrit :
>> This is an amazing example of being lazy - the Set is returned - and 
>> each call to iterator() will produce a result set ...
> 
> (...snip...)
> 
> how about a compromise: you gather all of the ids, keep a reference
> to the DataSource, and then issue a query every 100 object, loading
> the results in memory and closing the resultset and connection right
> away?

Just a note on the intend: one assumption behind AuthorityCodes was that it 
would have two typical usages:

* Get the AuthorityCode set and iterate over all the ID.
   This usage can be well handled by the above proposal.

* Just want to check if an ID exists, with:
   factory.getAuthorityCodes().contains(theID);

In the later case, gathering all ID is a more extensive work than needed. My 
attempt behind AuthorityCodes was to map "Set.contains(...)" to a simple "SELECT 
name FROM ... WHERE ID=?" in order to take advantage of database index without 
loading any of the 3000+ ID. This is a PreparedStatement that current 
AuthorityCodes keep as long as it is alive, it order to allow efficient 
execution of Set.containsAll(...) for example.

	Martin