CPSC 3720 - DAY 7
JANUARY 27, 2017

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	For this example, we will assume that we are employees at Amazon. 
Amazon sells products themselves, but also has users who sell products through 
the amazon service. Amazon would like to allow those users to sell items in an 
auction format, similar to eBay. Since Amazon already has services to sell 
items, many of the systems are already available, such as payment methods, 
listing an item for sale, searching for an item, viewing an item, 
emailing users, calculating shipment, purchasing shipping labels, and logging 
into the system.

A customer wants to bid on an item that they are already viewing. When they bid
the system will display the current bid, and the lowest next bid allowable 
(50 cents more than the current bid). The user can then enter the maximum 
amount they would like to bid. If the user has not logged in within the last 5 
minutes (check with the security system) then they are considered “inactive.” 
If the user is inactive the system should ask them to provide their password 
again before continuing. The system should verify the password with the 
security system. The amount the user enters as a bid must be higher than the 
minimum amount allowed. The system will then apply their bid to the item, and 
commence any automatic bidding (due to maximum bids being set by users). 
Automatic bidding is an included use case. The system will then display the 
current bid, as well as the current winner (not the final winner). The system 
will then notify anyone who has bid on this item of the change in the current 
bid.

USE CASE 1
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Title: Bid on an item.

Primary Actor: Customer

Secondary Actor: Seller, other bidders, security system, item database, 
	messaging system.

Preconditions: Customer is viewing the item, they are logged in, auction is 
		active.
Guarantees:

	Success:			Minimal:

	.New current bid		.System has not billed anyone
	.Notifications sent

Triggers: Customer finds item and indicates that they want to bid.

Goal Level: Sea Level

Main Success Scenario:			Extensions:

1. System displays current bid and 	2a. max amount < lowest allowed 
next bid.					i. display "bid too low"
						ii. return MSS step 2
2. Customer enters the maximum amount	3a. Customer is inactive
that they want to bid.				i. system asks for passwd 
						ii. customer provides passwd
3. System checks if customer is active		iii. return to MSS step 3
with security system.			4a. current bid < other customer max
					    bid.
4. System accepts new bid as lowest bid		i. AUTOBID system starts
allowable.					ii. finishes AUTOBID
						iii. return to MSS step 5
5. System displays current bid winner
and next allowable bid.

6. Notify seller and all customers via
auctioning system.