Søren Hilmer wrote: > > I propose the following change(s). > > Mainly for the supplied matchers and mailets I would like to > reconsider having > instance variables and methods being of private access and > move promote them > to protected access.
Lets look at the intent of this change which is (please correct me if I am wrong) to facilitate specialization by subclassing. This requires that classes follow a few simple rules: 1) Only expose as public methods that must be accessible to external classes and are guaranteed to be maintained throughout the class' development lifecycle. Such methods should ideally be defined in an interface. 2) Only make private methods which should never be exposed to subclasses, such as required constructors which only partially establish an instance's state, basic getters for lazily initialized variables, etc. 3) The remaining methods should be made protected. 4) Public and protected methods should be sufficiently granular to enable specialization of a sole behavior. The specializing method should not need to duplicate code in the superclass method. (If it does, refactor!) 5) All variables should be private and self-encapsulating, ie: access both within and without the class should be via getter and setter methods. Of the above, I would have thought only (5) is particularly contentious. Martin Fowler covers this in "Refactoring : improving the design of existing code", p171. Like Martin, I am willing to live with direct access within the defining class. Direct access from outside of the defining class should never be permitted as it breaks encapsulation and increases coupling. The specializing class should not need to know how a value is maintained and should simply invoke the getter/setter methods. These methods may access a variable directly, perform lazy initialization or delegate off to another class. The specializing class should neither know or care. So Søren, I am basically with you on making most methods protected but very much against making variables protected. Rather, we should make them private and add getter/setter methods! -- Steve - - - - - - - - - - - - - - - - - - This private and confidential e-mail has been sent to you by Synergy Systems Limited. It may not represent the views of Synergy Systems Limited. If you are not the intended recipient of this e-mail and have received it in error, please notify the sender by replying with "received in error" as the subject and then delete it from your mailbox. --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
