I am creating a web application in java where I need to mock the following flow.

When user trigger a certain process (add product to cart), I need to pass through following steps

1. Need to see in HTTP Session if user is logged in.
2. Check HTTP Session if shopping cart is there
3. If user exist in HTTP Session and his/her cart do not exist in HTTP Session
4. Get user cart from the database.
5. add item to cart and save it to HTTP session and update cart in DB.
6. If cart does not exist in DB, create new cart and and save in it HTTP Session.

Though I missed a lot of use cases here (do not want question length to increase a lot), but most of the flow will be same as I described in above steps.

My flow will start from the Controller and will go towards Service Layer and than ends up in the DAO layer.

Since there will be a lot of use cases where I need to check HTTP session and based on that need to call Service layer, I was planning to add a Facade layer which should be responsible to do this for me like checking Session and interacting with Service layer.

Please suggest if this is a valid approach or any other best approach can be implemented here?

One more point where I am confused is how to handle HTTP session in facade layer? do I need to pass HTTP session object each time I call my Facade or any other approach can be used here?