classes and attributes, sequence diagram and class diagram question:

Please show work for learning - if Visual Paradigm or another software is used, please provid large images or external links to large images.

Consider the following use case for eBroker.

Use Case name: Sell Stock

Normal Flow of Events:

1.The user enters the username and password

2.The system checks that the user is a valid user using information from the user database.

3.The user enters the stock symbol.

4.The system displays current price information for the stock.

5.The user enters sale transaction data such as number of stocks to sell and price

6.The system checks whether the user has adequate number of stocks in his account to sell.

7.The system creates a new sale transaction.

8.The system informs the stock exchange about the sale transaction.

9.The stock exchange informs the system (eBroker) when the sale is executed.

10.The system updates the users account.

11.The system terminates the sale transaction created in step 7.

I. Based on the above use case description, identify classes and attributes required to implement the use case.

II. Draw a sequence diagram that implements the above use case.

III. Based on your sequence diagram in question (II), identify the methods each class will have and complete the class diagram (that shows both attributes and methods)