Automated Restaurant System (Command Design Pattern)




You are to implement an automated restaurant system utilizing the Command design pattern, minimally consisting of the following three commands. You will then extend this basic system in any way that you choose to demonstrate the use of additional design patterns.

  • Display menu
  • Submit Order
  • Display tab


SCENARIO (of the basic system)

In the basic system, we assume that all orders are from the same table (i.e., there is only one table in the restaurant). Therefore, a tab is generated by simply totaling all of the ordered items, and tabs are not stored.


The menu of the basic system will consist of just main entrees. It will not include appetizers, desserts, drinks, etc. The information for each entrée will just be the name of the dish (“Roast Beef”, “Chicken Korma”, “Jiaozi”, etc.) and the price.



You should implement the Command design pattern. This includes the following:


  • Text-based user interface
  • SystemInterface class
classes of the Command design pattern
  • Invoker class
  • Command interface
  • Command classes (one for each command)
  • Aggregator class
  • Menu class
  • MenuItem Class
  • Orders class
  • OrderItem Class
  • Tab class


The user interface should just be a text-based numbered list of options, implemented in the main method. (It can be a GUI if you desire and are familiar with the development of GUIs, but no extra points will be given for this).


The SystemInterface can be a class of all static methods – one for each of the three commands of the user interface, if itdoes not have any state in your extension of the program.


The Aggregator classmaintains references to the Menu object and the Orders object. It should provide a getter method for retrieving the Menu and Orders objects (no setters are needed). The Menu and Orders classesstore a collection of MenuItem and OrderItemobjects, respectively. A MenuItem object will store the menu item #, the description, and its cost. An OrderItem object will store an order by its item number only (not its description).


The Invoker class has methods cooresponding to the methods of the system interface. Each method simply creates a Command object of the appropriate Command class (constructed with a reference to the Aggregator object), calls its execute method, and returns the results (as a single object) back to the system interface.(Execute methods should not be passed any parameter values – any values needed are passed to the constructor.)


A tab will be constructed from theTab class containing all of the ordered items, returned as an array of strings for the user interface to display. Note that a tab needs information from both the Menu and the Orders objects. (The Orders object indicates what menu items were ordered, and the Menu class has the description of each item to include in the Tab.)



You are to extend the design and capabilitities of the program in any ways that you wish. While the design may certainly call for the use of design patterns already used in the assignments this semester (i.e. Iterator, Factory, Strategy, and Decorator), the intent is to demonstrate the significant and appropriate use of design patterns not worked on in these assignments.


Following are some ideas on how the system may be extended:


  • Capability of maintaining orders (and tabs) for multiple tables.
  • Capability of maintaining a queue of waiting groups of different size to be seated, and

automatically seated as people leave tables (triggered when tab paid).

  • Capability of maintaining an inventory of items (tomatoes, etc.) and their depletion as

orders are prepared, which may have various effects (e.g., what is offered on the menu,

the price of certain items, the options offered for certain items)

  • Capability of “dynamic pricing” in which menu items change price based on factors such as

how well certain items is selling.

  • Capability of generating various reports (sales, inventory, etc.)
  • Capability of manager adjusting a given table’s tab based on some factors.
  • Anything else you can think of!