Includes changes made resulting from comments from Monica Martin.
This use case, describes an auction where a Seller offers for sale goods on which various Buyers can then bid. It includes several related parts:
All Buyers must register with the Seller before they can participate in auctions offered by the Seller. Buyer Registration is a separate choreography and consists of:
Note that this choreography may be used with other services offered by the Seller
The Seller sends a notification of the existence of an auction to a list of registered Buyers decided by the Seller. How the Seller decides who to notify is a private decision of the Seller. If the potential buyer wants to receive messages that relate to an auction, then they reply in the affirmative to the notification. A negative response from the buyer means that the buyer does not want to receive any messages associated with the auction. No response from a buyer is interpreted by the seller in the same way as a negative response. Note however, that a negative response from the Buyer does not stop the buyer from bidding (see later). The messages exchanges are:
Other registered Buyers may also discover the existence of the auction (e.g. see Auction Search below). In this case they may make requests at any time to receive messages about the auction. The messages exchange for this is:
If the Buyer no longer wants to receive any information about an Auction then they can send a message to the Seller requesting that the Seller no longer sends them any messages. The message exchanges are:
Once a buyer has requested that notification has stopped he may request that notifications start by sending an Auction Notification Request Message as above.
Any Buyer registered with the Seller, may place a bid on an auction at any time. They do not have to previously requested to be notified about the auction. If the Buyer had not previously registered to be notified then, placing a bid acts a request to be notified in the future. If the bid is less than the current high bid, the Bid is rejected otherwise it is accepted and all the buyers who are to be notified are informed of the bid. The message exhanges are:
Finally, the auction is closed e.g. because the time was up, or some particular value was reached. In this case the Seller notifies the winning Buyer (if there is one) and notifies all the Buyers (including the winning Buyer) of the result, e.g.. The message exchanges are:
If the winning Buyer does not respond to the Auction Win Notification Message within some timeframe (e.g. 1 day), then the Auction Win Notification Message is resent. This process is repeated several times (e.g. three times). If still no response is received from the winning buyer or the winning buyer, for some reason, declines to accept the auction result, then the Seller MAY contact an alternate "secondary" winning Buyer and offer to accept their bid and the process is repeated. Alternatively the Seller may give up in which case the Seller notifies all buyers of this.
The message exchange with a "secondary" winning Buyer is the same as for the initial winning Buyer except that the winning Buyer is under no obligation to accept the offer.
Whatever the reason or way in which the initial winning Buyer declines to accept, the Seller may seek damages by asking for a payment. The message exchanges for this are as follows:
If no response is received from initial winning Buyer, then Customer Support at the Seller must be notified and the problem is solved by other means.
All registered buyers may query the status of any auction at any time. The message exchanges are:
Any registered buyer may make a query about current auctions offered by the Supplier. This involves sending a parameterized query to which the seller responds with a list of auctions that match the parameters. The messages are:
The registered buyer may then use the information in the response to register for notifications, place bids, etc as described above.
David Burdett
Commerce One, January 15, 2004