Talk:Getter and setter policy

Don't tell me everyone agrees where is the fun in that?

I just have to completely agree with the first paragraph. I also try to always use this->FunctionName() to make the difference between internal and external function calls clear. Python, for instance, enforces such a syntax ( self.FunctionName() ). --TobiW

Very nice little style guide there, I would back that 100% --AlexGee 02:09, 28 July 2009 (UTC)

If the object has to call its getters and settings to change its own variables then changes to the variables internally would be subjected to the same constraints as calls through the public interface. This also would mean that internal calls would always have the same constraints as public calls. Would you want this? I mean might there be exceptions to this rule? --BenMcDonald 06:44, 28 July 2009 (UTC)

Sure there would be exceptions for example dealing with a collection. Thus I used 'ideally' --AlexGee 09:45, 28 July 2009 (UTC)

I know it would not be very nice design, but there is nothing stopping a developer from adding additional functionality to a getter/setter. If we want to stop that from happening, possibly this should also be included in the policy. Related to Command query separation. --Matthew Harward 21:04, 28 July 2009 (UTC)

After some research, my current opinion is: -"Objects should store all their data in private variables": Yes, this maintains encapsulation. -"Getter and setter methods should be produced for any variable you might have been tempted to declare public": HELL NO. This is wrong. Getter and setter = BAD. This breaks the concept of Tell, Don't Ask, the Law of Demeter, encapsulation and possibly (as Matthew has indicated) Command query separation in certain situations. Read this document: [1] to gain a better understanding of why it is wrong to use getter and setter methods. -"Classes should ideally call their own getter and setters when accessing their internal data": Yes, but only when you can't avoid using the Satanic getters and setters in the first place. Also, the get/set methods should comply with Command query separation. -- Douglas

Ok, having read the article, it does make a good point. However, please consider, the suggestions made by you and in the article may break the Behavioral completeness maxim. This may be an acceptable compromise. --Matthew Harward 00:26, 29 July 2009 (UTC)

I am not sure that it breaks the Behavioural completeness maxim, from my understanding it would actually support it. To use the truck suspension example, the wheel object can pass the force data to the axle object by saying: "here are some forces, deal with them", which places the responsibility for the behaviour task with the axle, which in real life (when massively simplified) is what happens. If I have misunderstood this principle please correct me. --Douglas 01:55, 29 July 2009 (UTC)

Maybe getters/setters should be treated with a DBC-like perspective. By this, I mean that getters and setters are allowed as long as you make it explicit what they are there for. E.g. if you hava a getName() method, this should have accompanying comments to say that this will get a String in format X that should only be got by classes in particular packages, or should be avoided or something. --Matthew Harward 00:30, 29 July 2009 (UTC)