Software Modelling and Design

Modelling,University.Posted March 2, 2015. 1185 words.

In this report, I model an auction system using the Unified Modelling Language.

Successful Scenario

  1. John wants to sell his old guitar.
  2. He visits the website of the Auction Website and is presented with a login screen.
  3. He enters in his correct Login ID and Password, he is logged in.
  4. The Auction Website lists current auctions and gives John the option to create a new auction.
  5. John enters in the name “acoustic guitar” and that the auction will end on Friday at 18:00 with a reserve price of £40. The Auction Website sets the start date to today.
  6. Another user puts a bid of £50 on the guitar. This is above the reserve price of £40.
  7. The Auction Website closes the auction on Friday at 18:00, preventing any new bids.
  8. The Auction Website sends a message to the buyer informing them that they had the highest bid and gives them the option to transfer money to John.
  9. The buyer transfers the £50 to John along with delivery details.
  10. John sends the guitar to the buyer.
  11. The Auction Website sends an email to the buyer to write a review on the experience and redirects the buyer to the reviewing page.
  12. The buyer gives John a review about how well the transaction went.

Failed Scenario

  1. Sarah wants to sell her diamond earrings.
  2. She goes to the login web-page of the Auction Website.
  3. The website displays text boxes for user-name and password.
  4. She enters in her user-name and password and logs in.
  5. The Auction Website lists current auctions and gives Sarah the option to create a new auction.
  6. She creates a new auction with the name of “Diamond Earrings” which finishes on Thursday at 17:00, she sets the reserve to £1500. The Auction Website sets the start date to today.
  7. The Auction Website closes the auction on Thursday at 17:00 and no bids have been made.
  8. The Auction Website notifies Sarah that her bid has closed and failed, she is presented with the option to start a new auction.

Cancelled Scenario

  1. Jess wants to sell her late grandmother’s wedding ring.
  2. She goes to the Auction Website and is presented with the login screen.
  3. She enters in her user-name and password.
  4. The website redirects her to the new auction screen.
  5. She creates a new auction with the name of “Golden Ring” which finishes on Friday at 10:00, she sets the reserve price to £450. The Auction Website sets the start date to today.
  6. Another user puts a bid of £500 on the auction.
  7. Jess chooses to cancel the auction and selects the “Cancel” option on the auction page.
  8. The website notifies her that she will get a penalty point associated with her account and presents her with the option to continue with the cancellation.
  9. Jess selects to continue.
  10. The Auction Website marks Jess’ account with a penalty point.
  11. Jess leaves the Auction Website.

Create Auction Use Case Diagram

Create Auction Use Case

Place Bid Use Case Diagram

Place Bid Use Case

Create Auction Bruegge & duToit Use Case

Use Case Name Create Auction
Actors Involved Seller
Entry Condition Seller is viewing the main page of our Auction Website.
Flow of Events 1. Seller clicks a link to log into the Auction Website.
  2. Auction Website prompts Seller for their Login ID and Password.
  3. Seller attempts to log into Auction Website using their Login ID and their Password.
  [Not Registered]
  4. Auction Website redirects Seller to the main page.
  5. Seller selects the ‘Submit Auction’ option.
  [Too Many Penalties]
  6. Auction Website presents the ‘Create Auction’ screen, asking for a name, reserve price, and end time.
  7. Seller enters in the name, reserve price, and end date of the auction.
  [Invalid Reserve] [Invalid Date]
  8. Auction Website presents a success message and a webpage dedicated to the Sellers auction is made.
  9. Seller is redirected to their new Auction so that they can confirm that it has been correctly created.
Exit Condition Seller’s Auction is now live. Other Users can bid on it until it ends.
Exceptions Not Registered Seller is not registered on the auction site, the auction cannot be created. Too Many Penalties Auction Website disallows the Seller from continuing to the ‘Create Auction’ page. Invalid Reserve The reserve price is invalid, and probably a negative number. Invalid Date The end date is in the past, as the auction will never open, we fail to create it.
Requirements Every Seller input should be responded to within 60 seconds. Any Exception should be clearly and concisely shown to the Seller so that they can take action to correct this if possible.

Place Bid Bruegge & duToit Use Case

Use Case Name Place Bid
Actors Involved Bidder
Entry Condition Bidder is currently viewing an auction on our Auction Website.
Flow of Events 1. Bidder clicks a link to log into the Auction Website.
  2. Auction Website prompts Bidder for their Login ID and Password.
  3. Bidder attempts to log into Auction Website using their Login ID and their Password.
  [Not Registered]
  4. Auction Website redirects Bidder back to the last Auction they were viewing, before they logged in.
  5. Bidder enters in the price they are going to Bid on this Auction.
  [Too Many Penalties] [Own Bid] [Bid To Low]
  6. Website displays a message to indicate that the Bid was successful. [Bid Cancelled]
Exit Condition Bidders Bid is displayed as the current highest bid on that Auction.
Exceptions Not Registered Bidder is not registered on the auction site, the auction cannot be created. Too Many Penalties The website disallows the Bidder from continuing to the ‘Create Auction’ page. Own Bid Seller is attempting to bid on their own auction, this is not allowed. Bid To Low The bid amount was lower than the current highest bid, the Website gives Bidder an option to enter in a higher amount or cancel the bidding. Bid Cancelled Seller cancels the auction, making it impossible for the bidder to place a bid.
Requirements Every Bidder input should be responded to within 60 seconds. Any Exception should be clearly and concisely shown to the Bidder so that they can take action to correct this if possible.

Class Diagram

Class Diagram

Success Sequence Diagram

Success Sequence Diagram

Failure Sequence Diagram

Failure Sequence Diagram

State Chart

State Chart