Mateusz Łoskot wrote: > [EMAIL PROTECTED] wrote: On Fri, Mar 31, 2006 at 03:45:25AM +0200, > Mateusz £oskot wrote: > >> I'd suggest to use "Shared Smart Pointer" semantic to manage >> geometry factories and their relations to geometry objects. One >> possibility is to use boost::shared_ptr (no linking to ext. libs >> required, just including one header, as <vector> or <list>). > > I agree on using shared pointer, but I don't think it takes a single > header.
You are right that smart pointer need more than single file to be shipped with them, but only one file needs to be included in client code. I have extracted Boost's smart pointers and it contains *only* headers. It's not so small package, around 2.7 MB, but if you want to use e.g. shared_ptr you need to inclyde *only* <boost/shared_ptr.hpp> file. So, for now, it is possible to include smart pointesr to GEOS source tree if you don't want to force users to download/install them theirself. > If you want to inspect this please do, and also remember Frank > request of making it possible for builders to choose between the > GEOS-embedded version and an external version of them (acting on the > -I switch would be enough). Yes, that's what I'm talking about. Boost provides tool called BCP. You can use this tool to extract a subset of libraries you want to use and ship them to users. >> Why not to use singleton or when to use it? >> >> Singleton is another option but *does* *not* apply to the current >> design, according to assumptions already confirmed. > > I might have used the wrong term, but by Singleton I meant a > "default" instance of a GeometryFactory, for use by calls w/out an > explicit provision of it. I don't know if it's worth the trouble, > when using shared_ptr. Probably not. Obsiously, well known is that Singleton is a single instance of some class. What I understand as a default factory that is not a Singleton? My understanding of the idea of default factory that is not a singleton is that it is not a single instance shared between geometries but it is represented as one-or-more factories having the same default state. It is a factory that is created with well known and well defined state. Such factory can be created many times for many geometries, e.g.: default_factory1 ---> geometry1 default_factory2 ---> geometry2 default_factory3 ---> geometry3 All three default factories are created separately and are separate objects. They just has the same state and provide same conditions for creating geoemtries. Cheers -- Mateusz Łoskot http://mateusz.loskot.net _______________________________________________ geos-devel mailing list geos-devel@geos.refractions.net http://geos.refractions.net/mailman/listinfo/geos-devel
