Should I build a wrapper around this entity?

Question

I have the following layout:

Entities:

Order
OrderItem

DAO classes:

OrderDAO
OrderItemDAO

So I have POCO classes, and DAO classes.

Now I want to encapsulate the above entities into another entity, so I can have methods like:

x.AddItem(OrderItem item)
x.CalculateTotal();
x.CalculateShipping();
x.Charge();

What would this type of entity be called? Factory? Or just a simple wrapper class?

Answer 1

It will definitely not be a factory (that could be the object that creates your "joint" entity, though). Possibly a wrapper, yes. But why not have the Order entity manage its OrderItems directly by creating a relationship between both?

Answer 2

Typically, I divide my code base into several layers: Modeling layer, Data Access layer, Manager/business-logic layer, and UI

In this case, I'd suggest leaving Order/OrderItem POCOs and creating an OrderManager class. It would be a stateless singleton, and have methods like AddItem(Order, OrderItem). Internally, it would deal with the specifics of updating the models, committing data changes, any transactionality, etc.

Answer 3

Sounds more like a Facade Pattern to me. Hide the actual implementation of the act of doing those various processes. Or in layman terms a wrapper would be correct.

See here: http://en.wikipedia.org/wiki/Facade%5Fpattern