The following is the process an account holder of eBroker, a discount online brokerage firm, uses to sell stocks.
The user first logs in by entering the username and password. The system checks that the user is a valid user using information from the user database. The user enters the stock symbol. The system displays current price information for the stock. The user enters sale transaction data such as number of stocks to sell and price. The system checks whether the user has adequate number of stocks in his account to sell. The system creates a new sale transaction. The system informs the stock exchange about the sale transaction. The stock exchange informs the system (eBroker) when the sale is executed. The system updates the user's account. The system terminates the sale transaction.
Write a use case description for the above process. Include only normal flow of events and exceptions. Make any reasonable assumptions, if required.