.. This file is part of the OpenDSA eTextbook project. See
.. http://opendsa.org for more details.
.. Copyright (c) 2012-2020 by the OpenDSA Project Contributors, and
.. distributed under an MIT open source license.

.. avmetadata::
   :author: Cliff Shaffer

=========
Project 1
=========

General Project Rules
---------------------

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* You **must** use Eclipse IDE, and you **must** use it to submit to
  Web-CAT.
  We won't accept submissions any other way.

* There are 4 projects during the semester, each has a 3-4 week
  lifecyle.

  * Each has three milestones, so about one/week.
  * P1's first milestone is really easy (make minor changes to the
    starter kit and submit to Web-CAT), and is due at 11pm on
    Wednesday, September 3.

* A major part of the project score is based on correctness, as
  defined by passing the reference tests at Web-CAT. We won't tell you
  a lot of detail about what is in the reference tests.

* A major part of the "correctness" score is adjusted by the quality
  of your own test suite (as defined by Mutation Testing coverage ---
  we will discuss this later).


Project 1: Movie Rater Database
-------------------------------

.. revealjs-slide::

* You will implement a "movie recommendation database".

  * Movies have an abstract index (a positive integer).

  * Reviewers have an abstract index (a positive integer).

  * A review is just an integer score from 1-10 for a given
    reviewer/movie pair.

* Besides storing, updating, and deleting reviews, you will support
  implementing a simple "similarity" score.

  * This idea is at the heart of "recommender" systems that permeate
    the internet.
    Recommender systems "recommend" things to you.


Data Representation
-------------------

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* The data structures challenge is how to store the ratings.

  * A natural approach would be to use an array.
  * But there are not many reviews for any given movie, and not many
    movies are reviewed by any reviewer.
  * So if we used an array, most positions would have "empty" values.
  * We solve this problem by implementing a "Sparse Matrix".    

    
Sparse Matrix
-------------

.. revealjs-slide::

.. image:: /Images/Sparse.png
   :width: 350
   :align: center
   :alt: Sparse Matrix


What We Give You to Get Started
-------------------------------

* We specify the class name for the project (MovieRaterProj), an
  interface that you must implement (MovieRater), and the name of a
  class that implements MovieRater (MovieRaterDB).

* This lets us write reference test cases for grading that make calls
  to the interface.

  * Reference tests do not write to System.out, or check the contents
    of System.out.

* We give you some initial tests (MovieRaterTest) that are meant to
  demonstrate all the requirements related to formatting the interface
  method return values.

  * If we get questions indicating that we left something ambiguous,
    we will update the example tests for you to see.
  * Important service: We will check any tests added to MovieRaterTest
    against the reference implementation. This lets you verify that
    your tests are correct (meaning, that you have no misconceptions
    about the project requirements --- if your tests are thorough).

* The project design is pretty simple, because all that you really
  need to add is the implementation for the Sparse Matrix.