Andrea Aime wrote: >> Andrea can we do any kind of "prescan" of the Expression? Ie making >> sure all the decisions are >> made once at the start of rendering - and then flying through >> expression evaluation at runtime? > Yes, we could. But that would add another level of care in order to > make things perform. I mean, we should be "average" out of the box, > that is, not suck from a performance point of view, nor be too hard to > use. Good - sounds like a "goal" for us then. (Notice the "prescan" would be your "compile" step...) >> At a programming level we could have something like the JDBC >> predefined statements. Or >> a utility class that you passed in your FeatureType and your >> "generic" Filter; and it gave you >> back one that had been optimized/simplified/defined. > The latter is the one I like the most. It would be something that is > provided with some insurance that the data structures are regular, > that is, you don't mix features and beans in the same collection, or > simple and complex features. > Wondering... couldn't the AttributeExpressionImpl simply assume the > accessor and converter are going to be always the same, and try to > recompute another only when the cached one fails? Wouldn't it be > even easier? Yes it would - and that is what I was trying to ask for earlier. It seems like a good assumption :-) It gets us the level of performance we want requires no configuration, and only the first Feature through is slowed down (the Feature through basically becomes the "scan" step). > I hear you. Your debugging concerns makes me think a lot. At the same > time, moving most of the filter and expression handling in an external > language is appealing, since we could move away a sizable amount of > code and maintenance effort, and gain in flexibility too (every scripting > language is more powerful than what we have now afaik). Well I think that we are bound by the Filter specification are we not? Well I suppose we can extend it with good ideas and just provide a mapping from Filter as needed. Are there any good query languages we could just steal in order to start out with? Say grab pure Java SQL implementation.... at least the mapping to and from Filter is well known.
Cheers, Jody ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Geotools-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-devel
