Marcos, Your answer and the excelent article of Graeme clarify the question.
If I want to change the type of the instance, better is to use generics. A factory is only a batch builder of the same objects. Graeme, your article opened my mind. The mappings and the registers caused me a very strong impression. Thank you! 2015-11-27 21:48 GMT-02:00, Marcos Douglas <m...@delfire.net>: > On Fri, Nov 27, 2015 at 7:44 PM, luciano de souza <luchya...@gmail.com> > wrote: >> If I need to do "TAnimalFactory.create(atDog) as Tdog", perhaps, it >> would be better not to use a factory, doing simply "TDog.create". > > You're right, use simply TDog.Create. > Why do you have a factory to create different types of animals > (classes)? Doesn't make sense. If you need a factory, you should use a > factory for dogs, another for cats and so on. > Another tip: Factories resolve some problems but there is a cost. The > factory will creates your instance (object) but it know only one > constructor, ie, the base class constructor. > Objects should be immutable at first place, only if you have a good > reason for don't use immutability. So, if they should be immutable, > you have only the constructor to instantiate your object, passing > arguments for it. If you have a constructor without arguments (using a > base class for example), you won't pass arguments to instantiate your > classe properly. > Another tip: use interfaces, not inheritance. Inheritance is evil. You > always will have problems using inheritance. Instead, use small > objects with few methods (2-5) to resolve just one problem. You don't > need inheritance for that. Your code will be more simpler and > customizable. > Decorator Pattern is more powerful than inheritance. Read about it. > > Best regards, > > Marcos Douglas > _______________________________________________ > fpc-pascal maillist - fpc-pascal@lists.freepascal.org > http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal > -- Luciano de Souza _______________________________________________ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
