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Thanks for the explanation Martin. Seems like that is a workable
design in Java, where the garbage collector worries about freeing the
factories for you when they are no longer referenced by any
geometries. I suppose I would probably split out the initial
conditions into some other object - so the factory just creates
geometries. But in the end, that doesn't change the issue I brought up. So, in C++ Geos could we use smart pointers to achieve the same effect? And maybe add in a default global factory? Charlie Martin Davis wrote: Those assumptions are correct. There were two main reason for designing the GeometryFactory concept:1) Provide a convenient, single location for defining the various "initial conditions" for Geometries. This includes the Precision Model, the CoordinateSequenceFactory, and sometimes the SRID. It may be extended in the future to contain things like which Polygon model to use, and preferences for precision handling. 2) Reduce the memory overhead of Geometries by moving relatively static objects (references) out of the Geometry and into a single shared object. Hopefully this makes sense... But if anyone has good opinions about another design pattern, send them along. Martin Davis, Senior Technical Architect Vivid Solutions Inc. www.vividsolutions.com Suite #1A-2328 Government Street Victoria, B.C. V8T 5G5 Phone: (250) 385 6040 - Local 308 Fax: (250) 385 6046-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Mateusz Loskot Sent: March 30, 2006 5:10 PM To: GEOS Development List Subject: [geos-devel] GeometryFactory - call for explanation Hi, Could anyone explain/confirm me assumptions behind the GeometryFactory class? Depending on its semantic I'd have some proposal to refactor it. Here are my qusetions: Are following assumptions correct? 1. Ever instance of Geometry type (or its subtype) can have assigned its own instance of GeometryFactory 2. One instance of GeometryFactory class can be shared (assigned to) between more than one objects of Geometry class 3. It is not assumed that all geometries share the same common instance of GeometryFactory Thanks in advance for comments Cheers -- Mateusz Łoskot http://mateusz.loskot.net _______________________________________________ geos-devel mailing list geos-devel@geos.refractions.net http://geos.refractions.net/mailman/listinfo/geos-devel_______________________________________________ geos-devel mailing list geos-devel@geos.refractions.net http://geos.refractions.net/mailman/listinfo/geos-devel |
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