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Asked: 2026-05-15T18:50:41+00:00

I just read a book on object-oriented programming patterns. It describes a Factory pattern

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I just read a book on object-oriented programming patterns. It describes a Factory pattern by which you can make a call to a static factory method of an object and the object will return a new object of expected type, but it will be subclassed appropriately.

My question, can this functionality be provided by a constructor for the class? If so how? I f not why? Imagine I have a class called VillagePerson, which has subclasses PoliceOfficer, NativeAmerican, Cowboy, Biker, ConstructionWorker, and Sailor. The constructor takes a text string description of the person, parses it, and returns the specific type of person that I want. Is this only possible with static factory methods?

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1 Answer

  1. Editorial Team

    This is a paraphrase of Steven Sudit’s comment

    Create a Proxy class on top of the VillagePerson:

    • The Proxy implements the same interface as VillagePerson, but does not inherit any implementation code from it.
    • A Proxy contains a reference _vpImpl to a subclassed VillagePerson object.
    • When a method is called on the Proxy, the Proxy simply passes the call to the _vpImpl object.

    To construct a subclassed VillagePerson, the Proxy’s constructor could call the specific constructor of the subclass and then store it in _vpImpl.

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