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POcalculation of the area of a rectangle
 

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    <p>I struggle organising my code, and I would like to share my "problem" with you by using a simple example: the calculation of the area of a rectangle. I put the code for example, but reading the first intro on each class section explains the situation easily.</p> <h2>Entity Rectangle:</h2> <p><strong>The entity Rectangle contains two inportant properties <code>$length</code> and <code>$width</code>.</strong> </p> <pre><code>// src/Acme/CalculationBundle/Entity/Rectangle.php /** * @ORM\Entity(repositoryClass="Acme\CalculationBundle\Repository\RectangleRepository") * @ORM\Table(name="rectangle") */ class Rectangle { /** * @ORM\Id * @ORM\Column(type="integer") * @ORM\GeneratedValue(strategy="AUTO") */ protected $id; /** * @ORM\Column(type="integer") */ protected $length; /** * @ORM\Column(type="integer") */ protected $width; </code></pre> <h2>FORM</h2> <p>Of course, the user can set length and width via a form</p> <h2>CONTROLLER</h2> <p><strong>CreateRectangleAction:</strong> renders the form on GET request and work on the data on a POST request.</p> <p><strong>ViewRectangleAction:</strong> shows the rectangle.</p> <h2>RECTANGLE MANAGER</h2> <p>Now, to make sure the controller doesn't do too much stuff, I use a RectangleManager to realise common operation on Rectangle objects and use it as a service (injecting the appropriate elements).</p> <pre><code>// src/Acme/CalculationBundle/Entity/RectangleManager.php use Doctrine\ORM\EntityManager; use Doctrine\ORM\EntityRepository; use Acme\EmployerBundle\Entity\Manager; class rectangleManager { /** * Doctrine entity manager * @var EntityManager */ protected $em; /** * @var EntityRepository */ protected $repository; /** * * @var string */ protected $class; public function __construct(EntityManager $em, $class) { $this-&gt;em = $em; $this-&gt;class = $class; $this-&gt;repository = $em-&gt;getRepository($class); } /** * @param $id * @return Rectangle */ public function find($id) { $rectangle = $this-&gt;repository-&gt;find($id); } </code></pre> <h2>THE PROBLEM: WHAT IF?</h2> <p><strong>What if I need to do some calculations on the rectangle?</strong> For example, if I need to add an area property so that I can render the area directly in the template without doing the calculation (length*width) in the template? </p> <p>Not knowing how to do this properly, I went for this pretty bad solution:</p> <p>I created a RectangleDisplay class (where I inject the rectangle entity) and display that entity instead of the Rectangle entity when calling ViewRectangleAction in the controller. </p> <pre><code>// src/Acme/CalculationBundle/Entity/ class RectangleDisplay { /** * @var Rectangle $rectangle */ protected $rectangle; /** * @var Integer */ protected $area; /** * @param Rectangle $rectangle */ public function __construct(rectangle $rectangle){ $this-&gt;rectangle = $rectangle; //calculate are $area = this-&gt;calculateArea($this-&gt;rectangle-&gt;getLength(),$this-&gt;rectangle-&gt;getWidth()); $this-&gt;area = $area; } /** * @return Integer $area */ public function calculateArea($length,$width) { return $length * $width; } </code></pre> <p>Now the property area is directly accessible in the template. In the case of a rectangle, that is fine, but in the case of a more complex element (cone, ...), I might want to use a service that is crazy at doing calculation. I am not gonna inject the container in my RectangleDisplayEntity, am I?</p>
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    1. COWhy don't you extend your Rectangle Model with methods you need? Just add there property, getters and setters - and you'll be able to get them wherever the model is called.
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      1. USVitalii Zurian
    2. COSure, that's much better! But how can I call the service container on this entity to use calculation methods that are specialised in this task. I don't know if it's a good Idea to use the service container in an entity, is it?
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    3. COYou don't need to have the service for calculations. Just move the calculation logic to getter method in the Model.
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      1. USVitalii Zurian
 

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