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<span class="dialogueheader">Take Assessment: Exercise 5</span><br><br>
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<h2 align="center">Using Design Patterns in the Gourmet Coffee System</h2>
<h3>Prerequisites, Goals, and Outcomes</h3>
<blockquote> <b><i>Prerequisites:</i></b> Before you begin this exercise, you
need mastery of the following:
<ul>
<li> <em>Object-oriented Programming</em>
<ul>
<li>How to define interfaces</li>
<li>How to implement interfaces</li>
</ul>
</li></ul>
</blockquote>
<blockquote>
<ul>
<li><em>Design Patterns</em>:
<ul>
<li>Knowledge of the singleton pattern</li>
<li>Knowledge of the strategy pattern</li>
</ul>
</li>
</ul>
<p> <b><i>Goals:</i></b> Reinforce your ability to use the singleton and strategy
patterns
</p><p> <b><i>Outcomes:</i></b> You
will demonstrate mastery in the following:
</p><ul>
<li>Producing applications that use the singleton pattern</li>
<li>Producing applications that use the strategy pattern</li>
</ul>
</blockquote>
<h3>Background </h3>
<p>In this assignment, you will create another version of the <em>Gourmet Coffee System</em>. This version will present the user with four choices:</p>
<blockquote>
<p>
<tt>[0] Quit<br>
[1] Display sales (Plain Text)<br>
[2] Display sales (HTML)<br>
[3] Display sales (XML)<br>
choice></tt></p>
</blockquote>
<p>The user will be able to display the sales information in three
formats:
plain
text, HTML, or XML. Part of the work has been done for you and is provided
in the student archive. You will implement the code that formats the
sales information. This code will use the singleton and strategy patterns. </p>
<h3>Description</h3>
<p>The following class diagram shows how the singleton and strategy pattern will
be used in your implementation:</p>
<blockquote>
<table border="0" cellpadding="2" cellspacing="2" width="75%">
<tbody><tr>
<td><img src="/content/SSD/SSD3/4.2.0.1/normal/pg-class-imp/pg-adv-clss-dsgn/assm-exer-dsgn-ptrns/pool-pr-dsgn-ptrns/qn-pr-formtr-gou-sys/handout/images/formttr-cof-gou-sys.jpg" alt="Figure 1 Portion of Gourmet Coffee System class diagram" height="426" width="627"></td>
</tr>
<tr>
<td><strong>Figure 1 </strong><em>Portion of Gourmet Coffee System class diagram</em></td>
</tr>
</tbody></table>
</blockquote>
<p>The elements of the pattern are:</p>
<ul>
<li>Interface <code>SalesFormatter</code> declares a method called <code>formatSales</code>
that produces a string representation of the sales information.</li>
<li>Class <code>PlainTextSalesFormatter</code> implements <code>formatSales</code>.
Its version returns the sales information in a plain-text format. </li>
<li>Class <code>HTMLSalesFormatter</code> implements <code>formatSales</code>.
Its version returns the sales information in an HTML format. </li>
<li>Class <code>XMLSalesFormatter</code> implements <code>formatSales</code>.
Its version returns the sales information in an XML format. </li>
<li>Class <code>GourmetCoffee</code> is the context class. It also contains
client code. The client code calls:
<ul>
<li> Method <code>GourmetCoffee.setSalesFormatter</code> to change the
current formatter</li>
<li>Method <code>GourmetCoffee.displaySales</code> to display the sales
information using the current formatter</li>
</ul>
</li>
</ul>
<p>In this assignment, you should implement the following interface and classes:</p>
<ul>
<li><code>SalesFormatter</code></li>
<li><code>PlainTextSalesFormatter</code></li>
<li><code>HTMLSalesFormatter</code></li>
<li><code>XMLSalesFormatter</code></li>
<li><code>GourmetCoffee</code> (a partial implementation is provided in the student archive)</li>
</ul>
<p>Complete implementations of the following classes are provided in the
student archive:</p>
<ul>
<li><code>Coffee</code></li>
<li><code>CoffeeBrewer</code></li>
<li><code>Product</code></li>
<li><code>Catalog</code></li>
<li><code>OrderItem</code></li>
<li><code>Order</code></li>
<li><code>Sales</code></li>
</ul>
<h4>Interface <code>SalesFormatter</code></h4>
<p>Interface <code>SalesFormatter</code> declares the method that every "Formatter"
class will implement.</p>
<p><em>Method:</em></p>
<ul>
<li> <code><em>public String formatSales(Sales sales)</em></code>. Produces
a string representation of the sales information.</li>
</ul>
<h4>Class <code>PlainTextSalesFormatter</code></h4>
<p>Class <code>PlainTextSalesFormatter</code> implements the interface <code>SalesFormatter</code>.
This class is implemented as a singleton so a new object will not be created
every time the plain-text format is used.</p>
<p><em>Static variable:</em></p>
<ul>
<li><code><em>singletonInstance</em></code>. The single instance of class <code></code><code>PlainTextSalesFormatter</code>.</li>
</ul>
<p><em>Constructor and methods:</em></p>
<ul>
<li> <code><em>static public PlainTextSalesFormatter getSingletonInstance()</em></code>.
Static method that obtains the single instance of class <code>PlainTextsalesFormatter</code>.
</li>
</ul>
<ul>
<li> <code><em>private PlainTextSalesFormatter()</em></code>. Constructor that
is declared private so it is inaccessible to other classes. A private constructor
makes it impossible for any other class to create an instance of class <code>PlainTextSalesFormatter</code>.</li>
</ul>
<ul>
<li> <code><em>public String formatSales(Sales sales)</em></code>. Produces
a string that contains the specified sales information in a plain-text format.
Each order in the sales information has the following format:
<pre>------------------------
Order <em>number</em>
<em>quantity1</em> <em>code1</em> <em>price1</em>
<em>quantity2</em> <em>code2</em> <em>price2</em>
...
<em>quantityN</em> <em>codeN</em> <em>priceN</em>
Total = <em>totalCost</em></pre>
where
<ul>
<li><em>number</em> is the order number.</li>
<li><em>quantityX</em> is the quantity of the product.</li>
<li><em>codeX</em> is the code of the product.</li>
<li><em>priceX</em> is the price of the product.</li>
<li><em>totalCost</em> is the total cost of the order.</li>
</ul>
<p>Each order should begin with a dashed line. The first order in the sales
information should be given an order number of 1, the second should be given
an order number of 2, and so on.</p>
</li>
</ul>
<h4>Class <code>HTMLSalesFormatter</code></h4>
<p>Class <code>HTMLSalesFormatter</code> implements the interface <code>SalesFormatter</code>.
This class is implemented as a singleton so a new object will not be created
every time the HTML format is used.</p>
<p><em>Static variable:</em></p>
<ul>
<li><code><em>singletonInstance</em></code>. The single instance of class <code></code><code>HTMLSalesFormatter</code>.</li>
</ul>
<p><em>Constructor and methods:</em></p>
<ul>
<li> <code><em>static public HTMLSalesFormatter getSingletonInstance()</em></code>.
Static method that obtains the single instance of class <code>HTMLSalesFormatter</code>.
</li>
</ul>
<ul>
<li> <code><em>private HTMLSalesFormatter()</em></code>. Constructor that is
declared private so it is inaccessible to other classes. A private constructor
makes it impossible for any other class to create an instance of class <code>HTMLSalesFormatter</code>.</li>
</ul>
<ul>
<li> <code><em>public String formatSales(Sales sales)</em></code>. Produces
a string that contains the specified sales information in an HTML format.
</li>
</ul>
<blockquote>
<ul>
<li>The string should begin with the following HTML: </li>
<blockquote>
<pre><html>
<body>
<center><h2>Orders</h2></center></pre>
</blockquote>
<li>Each order in the sales information should begin with horizontal
line, that is, an <code><hr></code>
tag. </li>
<li>Each order in the sales information should have the following
format:
</li>
</ul>
<blockquote>
<pre> <hr>
<h4>Total = <em>totalCost</em></h4>
<p>
<b>code:</b> <em>code</em>1<br>
<b>quantity:</b> <em>quantity</em>1<br>
<b>price:</b> <em>price</em>1
</p>
...
<p>
<b>code:</b> <em>codeN</em><br>
<b>quantity:</b> <em>quantityN</em><br>
<b>price:</b> <em>priceN</em>
</p></pre>
<p> where:</p>
</blockquote>
<ul>
<ul>
<li><em>quantityX</em> is the quantity of
the product.</li>
<li><em>codeX</em> is the code of the product.</li>
<li><em>priceX</em> is the price of the product.</li>
<li><em>totalCost</em> is the total cost of the order.</li>
</ul>
</ul>
<ul>
<li>The string should end with the following HTML:
<blockquote>
<pre> </body><br></html></pre>
</blockquote>
</li>
</ul>
</blockquote>
<h4>Class <code>XMLSalesFormatter</code></h4>
<p>Class <code>XMLSalesFormatter</code> implements the interface <code>SalesFormatter</code>.
This class is implemented as a singleton so a new object will not be created
every time the XML format is used.</p>
<p><em>Static variable:</em></p>
<ul>
<li><code><em>singletonInstance</em></code>. The single instance of class <code></code><code>XMLSalesFormatter</code>.</li>
</ul>
<p><em>Constructor and methods:</em></p>
<ul>
<li> <code><em>static public XMLSalesFormatter getSingletonInstance()</em></code>.
Static method that obtains the single instance of class <code>XMLSalesFormatter</code>.
</li>
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