获取类方法的参数列表

Question

What I'd like is for this class

class Car {
    public function __construct(Engine $engine, Make $make, Model $model)
    {
          // stuff
    }
}

Get an array that has the types needed to construct this car (Engine, Make, Model) in the order they are needed for the constructor. I'm using this for a Dependency Injection-esque thing I'm making.

Update: I made these classes to accomplish the task but I feel like there is still a better way:

    <?php
    class Engine{}
    class Make{}
    class Model{}
    class Car {
        public function __construct(Engine $engine, Make $make, Model $model,
        $foo,
        $cats = 'dogs',
        Engine $anotherEngine = NULL)
        {
              // stuff
        }
    }
    class ServiceParameter extends  ReflectionParameter
    {
            public $type = NULL;

            public function __construct()
            {
            $args = func_get_args();
            call_user_func_array(array('parent', '__construct'), $args);
                    $str = parent::__toString();
                    $str = explode(" ", $str);
                    $str = $str[4];
                    if(substr($str, 0, 1) != '$')
                            $this->type = $str;
            }

    }
    class ServiceMethod extends ReflectionMethod
    {
        private $_parameter_cache = NULL;
        private function _wrapParameter(&$item, $key)
        {
            $item = new ServiceParameter(array($item->getDeclaringClass()->name,
                 $item->getDeclaringFunction()->name),
                $item->name);

        }
        public function getParameters()
        {
            if(is_array($this->_parameter_cache))
                return $this->_parameter_cache;
            else
            {
                $rms  = parent::getParameters();
                array_walk($rms, array($this, '_wrapParameter'));
                $params = $rms;
                $this->_parameter_cache = $params;
                return $params;

            }
        }
    }


    $c = new ServiceMethod("Car", "__construct");
    $args = $c->getParameters();
    foreach($args as $arg)
    {

        echo "Parameter Name: {$arg->name}
";
        echo "GetName: {$arg->getName()}
";
        echo "Type: {$arg->type}
";


    echo "

";
}

Which outputs:

Parameter Name: engine
GetName: engine
Type: Engine


Parameter Name: make
GetName: make
Type: Make


Parameter Name: model
GetName: model
Type: Model


Parameter Name: foo
GetName: foo
Type: 


Parameter Name: cats
GetName: cats
Type: 


Parameter Name: anotherEngine
GetName: anotherEngine
Type: Engine

I know there's some redundant stuff ($params = $rms) but that's a result of rushing and changing the code around a lot to get it to work. I feel like constructing a whole new ServiceParameter when we already have the ReflectionParameter instance is a waste. Is there anyway around this ($item = (ServiceParameter)$item didn't work)

Answer 1

class Engine { }
class Make { }
class Model { }
class Car {
  public function __construct(array $a, $b, Engine $engine, Make $make, Model $model)
  {
    // stuff
  }
}


$rc = new ReflectionClass('Car');
$ctor = $rc->getConstructor();
foreach( $ctor->getParameters() as $rp ) {
  $cn = $rp->getClass();
  if ( $cn instanceof ReflectionClass ) {
    $cn = $cn->getName();
  }

  echo $cn, ' ', $rp->getName(), "
";
}

prints

 a
 b
Engine engine
Make make
Model model