This is an exhaustive post
. Let me try to answer the questions.
1. Association between the product and order: If you check the class diagram again you can see that Order-->OrderItem--->Product relationship.
2. Changes to the BDOM: Class diagram didnot change the BDOM. It just elaborated BDOM adding more components and created more detailed view (class) using BDOM as base.
Now let me try and answer other questions.
A. How to implement the busniness logic with above technologies? How would these look in our class diagram?
Answer to first part of the Question: First we need to move the detailes provided BDOM in to different TIER (Client, Presentation, Business & EIS / DB)
Answer to second part of the Question: Now for each tier we have to start designing.
Client Tier - Create user experiance
Presentation Tier - Create class diagrams
Business logic - Create class diagrams
EIS / DB Tier - Create ER diagram based on the BDOM.
Other than class diagrams we might want to use Activity, Sequence, Collaboration diagrams. These diagrams will be very useful during the implementation. These are optional and can be used based on the need.
B. What about Persistence? How would this look like in our class diagram?
There are two aspects to persistence:
1. Class diagrams: EJB's represent datastore in terms of java object, it can also be DAO or may be POJO's that is used to access data.
2. ER diagrams: This will be useful to design the database and will be very useful to care to create DB.
I hope this is helpful and i expect other to contribute.