This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
A few months ago I met and I implemented a design pattern (just for example) called Actor-Role that represent very types of people (persons and organizations) and the various roles they represent (customer, employee, company, supplier, etc).
I wonder if there is a consensus or pattern which would apply to the management of documents such as Invoice, Order, Payroll, Budget, Quotation, etc.? Once these documents have certain dependencies and common features which can be converted from one type to another (eg Quotation -> Order -> Invoice)