There are thousands of published design patterns, so we cannot cover them all. This assignment gives you experience with reading about a new pattern, building a project to illustrate using that pattern, and presenting the pattern to your classmates. This helps develop the curiosity attribute that is an important element of the MSOE Mindset. An important element of this project is to identify a single, interesting, non-trivial advantage of the pattern, and to build your presentation so you examine this advantage from multiple perspectives so that your peers will understand a key benefit of using the pattern. You will present your chosen pattern and demonstrate your project during the final lab session.
In this first phase, you will
There are several constraints on the application:
The full implementation of the application will not be due until phase 2. The goal in phase 1 is to make plans; implementation will come later.
See below for the discussion of the presentation slide deck that you must create for phase 1. Keep in mind that all teams typically present during the final 120-minute lab, so this gives you a target time limit. Note that the demonstration is near the start of the presentation because it gives important context for your peers when they are trying to understand the pattern. Read through the other presentation notes as you construct your phase 1 draft.
As stated above, the presentation is to focus on the single advantage you are highlighting. The idea is that this is the primary takeaway for your audience. Word it carefully: it needs to be memorable. Reinforce this advantage from multiple perspectives such as its use in the demonstrated code, how it is captured in the design, different ways the pattern appears in large, real systems, etc. Note the use of “such as” in the previous sentence! What is appropriate for one presentation may not be appropriate for others. The key is to leave the audience with both a general understanding of the pattern and the key advantage you are highlighting.
In the second phase of the project, you will actually implement your example program that illustrates your one key idea. During this phase, you may make minor changes to your design as you discover new things about your pattern. You will adjust your presentation to reflect these minor changes. You may find it helpful to read the requirements for this implementation as you brainstorm.
You will work in teams of three or four as organized by your instructor. How you divide up the work is up to the team, but all must participate in a meaningful way. In particular, everyone must both present and help write the implementation. A significant part of your grade will be based on a short report in which you describe how you contributed.
Your project will be evaluated, in part, according to the Exhibit Curiosity SWE2410 Rubric, which your instructor will provide you.
Do not pick any of the patterns covered in class: Command, Composite, Decorator, Façade, Factory (in any of its variants), MVC, Null Object (not always covered in class, but not extensive enough to make a good example), Observer, Singleton, Strategy, or Visitor. There are a number of patterns covered in textbooks that can be selected: Builder, Chain of Responsibility, Flyweight/Object Pool, Interpreter (Advanced GoF pattern), Mediator, State, and Twin. But there are many other good choices; see sites like OODesign.com and wikidot for some ideas. You can find more such sites by searching for “catalog of software design patterns”. Cloud patterns, such as those listed at Microsoft, are also possibilities, though do not select Functions as a Service (e.g., AWS Lambda), Pub/Sub, or Step Functions since these are covered in class.
Avoid the following patterns:
Your pattern must be approved by the instructor. Patterns are available on a first-come, first-serve basis. Cloud patterns are fine choices, but should be avoided unless team members have had experience with web-based development.
As you consider the patterns, consider whether there is an interesting, complex advantage of the pattern that you can make simple for your peers. Also consider what “real world” GUI program you could develop to illustrate this advantage. These two ideas will eventually be assessed in the Exhibit Curiosity SWE2410 Rubric under the Exploration and Innovation headings.
Develop a draft presentation that includes the following:
The goal of developing a draft at this point is to help ensure your application does illustrate your pattern. We understand you will likely need to make changes to your presentation as you complete the implementation, but it is important to start with a solid structure and the expectation is that the final presentation will not be a complete rewrite. Write the presentation as if the example program already exists. For example, your class diagrams should use names for classes you plan to write in your example program.
The following items are not required, but you should strongly consider including at least some:
All of these perspectives should key into your demo app, showing details from the app rather than abstractions or other example programs that are out there. Sometimes, an additional example beyond your app may also be useful, but should not replace tie-ins to your example application.
Many of these perspectives – especially the required mockups, UML class diagrams and code snippets – can be enhanced by contrasting them to a solution that does NOT use the design pattern. In some cases, you may wish to even implement the alternative solution, e.g., to show a performance advantage of the design pattern or to work out what the alternative is more clearly in your own mind.
Do NOT attempt to describe your entire demo application’s source code in your presentation. Class diagrams should include only those classes that support the goal of illustrating key elements of how the pattern is applied to your project. In particular, do not include all attributes and methods within each class. Likewise, code snippets should be just long enough to illustrate your point. You will may need to develop multiple diagrams and combine diagrams with different code snippets (which may be on a diagram!) to illustrate different aspects of the pattern and the pattern’s key advantage. This is an art. The whole team should review each perspective to ensure the level of detail is just right.
Your presentation will be evaluated according to the Exhibit Curiosity SWE2410 Rubric. As you look at multiple perspectives, focus on the Perspectives and Intellectual Inquiry dimensions of the rubric.
Submit your draft, including the associated code, as directed by your instructor.