13.4. Revisiting the auction application

At this point, you may want to browse through chapter 3 to remind yourself about the auction application. With all you’ve learned in the chapters since chapter 3, it’s evident that the auction application has a lot of room for improvement. But to keep things manageable, let’s focus on the auction implementation, or more specifically, on the auction.auctioneer.sealed_1.0.0 bundle. In the next section, we’ll simplify the whole design of the auction application through events.

13.4.1. Using the Event Admin service

One of the complexities of the auction application is that we ended up having to develop an extensible mechanism for allowing auditors to know what’s happening in the auctions. This was done by wrapping the Auction services with the AuctionWrapper class in the auction.core bundle. A more decoupled approach would have been for the Auctions to post events informing of the ask and bid activities and letting the auditors listen for them. You could even use the same approach to inform the sellers and buyers of the outcomes of their asks and bids, decoupling not only the auditors from the auctions but the participants as well.