Random Thoughts and Questions

Some random thoughts and questions....

If two objects of the same class have different rules, how did they get those different rules? Was there some object factory that gave them different rules? If other objects modify an object's rules, is that a violation of encapsulation? If an object is the only entity allowed to modify its rules, that means that it must know about all possible rules it can have within the domain. For some domain types (e.g. account types) where there is a closed set of kinds, this might not be a bad idea. For open ended domain types (e.g. widgets) this could not possibly work.

In the case of the Customer class, what would be involved when giving a Customer a discount? We certainly need to specify and store the amount of the discount. But do we also add a rule to the class? Or was the rule there all along waiting for a discount attribute to be set? Since rules may operate on attributes, it's important to keep them in sync. If you have a rule that expects a discount attribute but no discount attribute is in your object's Description Object, your rule will fail or misbehave.

Also it seems like a Description Object might encounter name collision issues. Perhaps there should be namespaces within a Description Object?