Homework: WaitingLine Family Interface Design

This homework is necessary preparation for the lab. Make sure you type your answers and you bring the files to the lab so that you will not have to waste time entering them during the lab.

1. For this homework, you will design the interfaces for a new component family, WaitingLine. WaitingLine is trying to capture the idea of a waiting line like you might encounter at a restaurant. Customers upon arriving at the restaurant have their name added to the end of the waiting line; they can ask for their position in the waiting line and perhaps later decide to leave and ask to be removed from the waiting line. Customers are seated in the order in which they are added to the waiting line. Note that a restaurant is just one example of where such a waiting line may be useful. There are many other situations where waiting lines occur and your components should be applicable to such other situations as well. WaitingLine is similar to Queue in that it provides a FIFO (first-in-first-out) order of processing, but differs from Queue in the following significant ways:

   • The entries in a WaitingLine must be unique.
   • It must be possible to remove a given entry known to be in a WaitingLine.
   • It must be possible to find the position of a given entry in a WaitingLine.

   Starting from the interfaces Standard, QueueKernel, and Queue, design new interfaces WaitingLineKernel and WaitingLine to capture the behavior of a waiting line. For this homework, turn in PDF print-outs of the WaitingLineKernel.java and WaitingLine.java files.