Le 04/09/2012 08:13, Bruce a écrit : > As usual this is hard to explain in a short message, but here goes. > > We have a major library that provides all the persistence mechanisms for > what we call "Business Objects". In our case it's Horses, Stables, > Auctions, Trainers, Owners, etc etc, currently 38 of them and growing. > The reason for this is that the database design changes incrementally on > a frequent basis when one of the clients comes up with another good > idea. With 166 different applications to support, it makes sense to cope > with data changes in one central library. > > I have been trying to abstract a lot of the methods in the library > classes and have got to the point where the majority of the common logic > is contained in two major classes, and its all driven by metadata "maps" > that relate the BO attributes to the relevant columns and tables in the > database (and vice versa). > > The roadblock I have now struck is this. Each BO class requires a > special "partner class" that contains the metadata as a static > attribute. Each of these classes now looks exactly the same, same data > items, same code. The only difference is the class name. Thus, 38 > different classes - all exactly the same. But at runtime, obviously, > each has a different metadata map loaded. > > What I'd like to be able to do is have only one of these, rather than > 38. > > The reason that the metadata is held as a static attribute is that > during any execution of a given program, there might be hundreds > (sometimes thousands) of, say, Horse objects created. So it makes sense > to only load the metadata once and share it amongst all the BO's of that > type. > > So, is there some way to create a class i.e. a new class not a new > object, based on that common code at runtime? > > I have attached a picture that I hope might help in understanding where > I'm coming from. It's the brown classes inside the pinkish box. > > I've tried looking at design patterns for something like this but really > can't find anything that seems to match. > > regards > Bruce >
I don't understand everything, so maybe I will tell rubbish: if all these classes share the same code, why not using inheritance? -- Benoît Minisini ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Gambas-user mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/gambas-user
