Release date: Wednesday, 21.05.14 - Due date: Sunday, 25.05.14, 23:59
In the lecture we discussed the differences between Checked and Unchecked Exceptions. Go through the following list of conditions and decide whether this information should be represented as Checked Exception, Unchecked Exception, or as regular element of the program flow (typically return values of type boolean or of an enumeration type). Give for each decision an argument (one sentence). In case your answer depends on a context, explain which context you are assuming.
After our discussion in Task 22 in the last assignment we decided to develop the component that allows to find cloud BAKERY 2100's nearby as a server component. The component gives a list of the 5 closest cloud BAKERYs if you pass the GPS coordinates as parameters. In the following you will discuss the availability of this component.
a) In the lecture we discussed two strategies to detect whether a component is available or not. Describe each in one or two sentences. Discuss which one is appropriate here. (2-4 sentences should be enough. Of course you can use as well the predefined format from the recent tasks.)
b) We mentioned the following tactics to handle failures. Discuss which one is appropriate here. (2-3 sentences per tactic should be enough. Of course the predefined format from the recent tasks could be especially helpful here as well.)
Based on task 27, previous lectures and some creativity.
Finally we describe one error handling strategy in detail.
Assume that due to cost restrictions
We decided to deploy a list of cloud BAKERYs by PLZ (Postal Code) on the mobile device. In case the mobile device is not able to get the list of closest cloud BAKERY, it will offer to find it by PLZ based on this local list.
Draw a sequence diagram that illustrates the case of a failure and how it will be handled by the mobile device.
The sequence diagram should contain at least one or a few objects as part of the client, the stub representing the server object on the client, the server object, and one or more objects representing the middleware framework. (You might want to have a look at the slide 20 of chapter 9).
a) Connect the cloud BAKERY 2100 station to the server.
<experiment> optional even within the optional task:
Your task: (You don't need to take part in the experiment, but you would be very welcome to do so.)
Check out the projects from the samplesolutions folder:
plus the project:
A07T29_CloudBakery2100Stationfrom your repository
This version of the cloud BAKERY 2100 is already mostly distributed. That is easy to check:
CloudBakery2100Serverproject. It has no UI but writes a line to the console.
CloudBakery2100CustomerClient won't show anything else than the login view without the server.1) If you look into the source code, you see as well that
the list of baked goods now comes from the server. The
CloudBakery2100Station is not yet connected to the server.
Your task is simply to study how the
CustomerClient connects to the server and to let the
Station connect with the server as well.
Implement the methods
getPlacedOrders in the
If you help us with the experiment, please do finally the following:
b) We created quite some code for the “cloud BAKERY 2100”. We tried to stay close to our models and respect the things that the lecture is teaching. Review the implementation with all your knowledge about Requirements Engineering and System Design. List up to six aspects of the implementation and discuss whether the implementation is as it should be or whether we need to improve it. (2-3 sentences plus clear indications to what part of the code you refer).