FactoryAfter.php

<?php

abstract class enemyShip {
    protected $name;
    protected $amtDamage;
    
    public function setName($newName) {
        $this->name = $newName;
    }
    
    public function getName() {
        return $this->name;
    }
    
    public function setDamage($newDamage) {
        $this->amtDamage = $newDamage;
    }
    
    public function getDamage() {
        return $this->amtDamage;
    }
    
    public function followHeroShip() {
        echo $this->getName() . " is following the hero <br/>";
    }
    
    public function displayEnemyShip() {
        echo $this->getName() . " is on the screen <br />";
    }
    
    public function enemyShipShoots() {
        echo $this->getName() . " attack and does " . $this->getDamage() . "<br />";
    }    
}

class UFOEnemyShip extends enemyShip {
    public function __construct() {
        parent::setName("UFO Enemy Ship");
        parent::setDamage(20);
    }
}

class RocketEnemyShip extends enemyShip {
    public function __construct() {
        parent::setName("Rocket Enemy Ship");
        parent::setDamage(10);
    }
}

class BigUFOEnemyShip extends UFOEnemyShip {
    public function __construct() {
        parent::setName("BigUFO Enemy Ship");
        parent::setDamage(40);
    }
}

class EnemyShipFactory {
    // Encapsulate ship creation
    // When we have to modify something, this is the only one place where we gonna have to make those modifications
    public function makeEnemyShip($newShipType) {
        if ($newShipType == "u") {
            return new UFOEnemyShip();
        } elseif ($newShipType == "r") {
            return new RocketEnemyShip();
        } elseif ($newShipType == "b") {
            return new BigUFOEnemyShip();
        }
    }
}

// After using Factory Design Pattern
class enemyShipTesting {
    public function __construct() {
        if (isset($_POST['type'])) {
            $factory = new EnemyShipFactory();
            $ufoShip = $factory->makeEnemyShip($_POST['type']);
            
            $this->doStuffEnemy($ufoShip);         
        } 
        
        echo '<form method="post">',
                 '<label for="type">Type: </label>',
                 '<input type"text" id="type" name="type" />',
             '</form>';
    }
    
    public function doStuffEnemy(enemyShip $anEnemyShip) {
        $anEnemyShip->followHeroShip();
        $anEnemyShip->displayEnemyShip();
        $anEnemyShip->enemyShipShoots();
    }
}

$testing = new enemyShipTesting();