Hi all. I am refactoring a existing application, where I have a Product class that stores mainly the stock (productName, creationDate, updateDate, amountStocked, minimumAmount and maximumAmount).
But now I have to store historics of some modifications(like, everytime that the stock of a product is modified, that modification goes to the historic). The problem is that I have to do historic storing the last value AND the date. For example, if the amountStocked is modified, the last amount have to be stored with the update date, linked to the product. I was thinking in something like a Set of a object that stores only the value(mostly Doubles) and the dates(java.util.Date) in Product class, but I don't know if this is the best approach. What are the best practices to do such things?

Thanks in advance and best regards to all

Rafael Mauricio Nami

Maybe this is a good starting point using "interceptors" http://www.hibernate.org/195.html

Check out the appropiate Interceptor part of the manual.