指定子類中的變量父

Question

類

我有這些相關的類：

class cars { 

    public $cars; 

    public function addCar($name, $car) 
    { 
     $this->cars[$name] = $car; 
    } 

    public function getCars() 
    { 
     return $this->cars; 
    } 

    public function getCar($name) 
    { 
     return $this->cars[$name]; 
    } 

    public function getParams() 
    { 
     return $this->params; 
    } 
} 

$cars = new cars(); 

class bmw extends cars { 

    private static $_instance = null; 
    protected $params; 

    function __construct() 
    { 
     $this->params['param'] = 'foo'; 
    } 

    public static function init() 
    { 
     if (self::$_instance === null) { 
      self::$_instance = new self; 
     } 

     return self::$_instance; 
    } 
} 

$cars->addCar('bmw', bmw::init()); 

基本上我需要從父類訪問所有子類。並使用父類中定義的方法定義這些子類。添加新的子類時不應修改父類。

到底這應該是這樣的：

foreach($cars->getCars() as $car) 
{ 
    foreach($car->getParams() as $key => $param) 
     echo "$key = $param"; 
} 

什麼是做到這一點的正確方法？

Answer 1

提供幫助確實很困難，因爲它不太清楚你想要達到的目標。

在我看來，你需要註冊表類（carDealer），這是一個抽象類，具有共同的（對於每個孩子）方法和一個孩子（Bmw）。

所以，像這樣：

// You seems to need what is called sometimes a Registry. 
// Something which deal with keeping and delivering a group of 'related' classes, as a register. 
class CarsDealer 
{ 
    public $cars; 

    public function addCar($name, $car) 
    { 
     $this->cars[$name] = $car; 
    } 

    public function getCars() 
    { 
     return $this->cars; 
    } 

    public function getCar($name) 
    { 
     return $this->cars[$name]; 
    } 
} 

// then you need a basic contract for each concrete classes 
// that will have the same nature and so will extend it 
abstract class Car 
{ 
    protected $params; 

    public function getParams() 
    { 
     return $this->params; 
    } 
} 

// finally the concrete class 
class Bmw extends Car 
{ 
    public function __construct($params = null) 
    { 
     $this->params['param'] = $params; 
    } 
} 

$carsDealer = new CarsDealer(); 

$carsDealer->addCar('bmw', new Bmw('foo')); 

foreach ($carsDealer->getCars() as $car) 
{ 
    foreach ($car->getParams() as $key => $param) { 
     echo "$key = $param"; 
    } 
} 

請注意一些基本規則/良好做法/慣例：

• 類命名，總是大寫
• 責任（一類寶馬不該」 t有一個方法getCars，至少在本例中不是這樣）
• Visibility方法，參數
• http://www.php-fig.org/psr/psr-1/
• http://www.php-fig.org/psr/psr-2/

Answer 2

只是一個另一種方法，如果你只需要得到這個 'PARAMS' :-)

class cars { 

    public $cars; 

    public function addCar($name, $car) 
    { 
     $this->cars[$name] = $car; 
    } 

    public function getCars() 
    { 
     return $this->cars; 
    } 

    public function getCar($name) 
    { 
     return $this->cars[$name]; 
    } 

    public function getParams($obj) 
    { 
     return $obj->params; 
    } 


} 

$cars = new cars(); 

class bmw extends cars { 

    private static $_instance = null; 
    protected $params; 

    function __construct() 
    { 
     $this->params['param'] = 'foo'; 
    } 

    public static function init() 
    { 
     if (self::$_instance === null) { 
      self::$_instance = new self; 
     } 

     return self::$_instance; 
    } 
} 

$cars->addCar('bmw', bmw::init()); 

print_r($cars->getParams($cars->getCar('bmw')));