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POCan a object "evolve" into an object of one of it's child classes?
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copied!<p>Assume we have a parent class and a child class. The parent class checks some parameters and decides that the child class would be better suited to handle the given request - is there a way to recreate the existing (parent)-object as an object of the child class from whithin the parent object?</p> <p>Example of a parent class:</p> <pre><code>/** * Simple car */ class car { /** * The constructor */ public function __construct() { // (...) } /** * Add a sunroof to the car */ protected function addSunRoof() { // (...) } /** * Parse a config string and configure the car accordingly * @param string $config */ public function configure($config) { $options = explode(";", $config); // Do something for every option in $config string foreach ($options as $o) { switch ($o) { case "sunroof" : $this->addSunRoof(); break; case "4x4" : // 'car' does not have support for '4x4', but the child class 'suv' does // -> This 'car' object should therefore 'evolve' and become a 'suv' object - how? case "foo" : // (...) } // switch } // foreach } // configure } // car </code></pre> <p>Example of the child class:</p> <pre><code>/** * SUV car */ class suv extends car { /** * Add 4x4 drive */ protected function add4x4() { // (...) } // add4x4 } // suv </code></pre> <p>Now, the most obvious way to get a <code>suv</code> object would be to create it directly from the beginning:</p> <pre><code>$car = new suv(); $car->configure($config); </code></pre> <p>The challenge is that I don't know whether a <code>car</code> or a <code>suv</code> object is required when creating the object; I don't know what options the <code>$config</code> string contains until it gets parsed in the <code>$car->configure()</code> method (The string can come from anywhere, e.g. user input).</p> <p>A simple workaround would be to move the <code>configure</code> method out of <code>car</code> to analyse the string before creating any object - however, it logically belongs to the <code>car</code> object, so I would really like to keep it there :)</p> <p>Is there a way to solve this puzzle? If not, what would you suggest as the "cleanest" workaround?</p> <p>Thanks in advance!</p> <p><strong>Edit:</strong></p> <p>As it was pointed out, my question is very similar to this one: <a href="https://stackoverflow.com/questions/4080217/cast-the-current-object-this-to-a-descendent-class">Cast the current object ($this) to a descendent class</a> The answers there are saying that it's technically possible, but should not be done. However, a convincing alternative has not been suggested yet (It has been suggested to use factories, but I feel this would only solve a part of the problem).</p>

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