获取父类中子类的名称(静态上下文) [英] Getting the name of a child class in the parent class (static context)

问题描述

我正在构建一个 ORM 库，考虑到可重用性和简单性；一切都很好，只是我被一个愚蠢的继承限制卡住了.请考虑以下代码:

I'm building an ORM library with reuse and simplicity in mind; everything goes fine except that I got stuck by a stupid inheritance limitation. Please consider the code below:

class BaseModel {
    /*
     * Return an instance of a Model from the database.
     */
    static public function get (/* varargs */) {
        // 1. Notice we want an instance of User
        $class = get_class(parent); // value: bool(false)
        $class = get_class(self);   // value: bool(false)
        $class = get_class();       // value: string(9) "BaseModel"
        $class =  __CLASS__;        // value: string(9) "BaseModel"

        // 2. Query the database with id
        $row = get_row_from_db_as_array(func_get_args());

        // 3. Return the filled instance
        $obj = new $class();
        $obj->data = $row;
        return $obj;
    }
}

class User extends BaseModel {
    protected $table = 'users';
    protected $fields = array('id', 'name');
    protected $primary_keys = array('id');
}
class Section extends BaseModel {
    // [...]
}

$my_user = User::get(3);
$my_user->name = 'Jean';

$other_user = User::get(24);
$other_user->name = 'Paul';

$my_user->save();
$other_user->save();

$my_section = Section::get('apropos');
$my_section->delete();

显然，这不是我期望的行为(尽管实际行为也有道理).所以我的问题是你们是否知道在父类中获取子类名称的方法.

Obviously, this is not the behavior I was expecting (although the actual behavior also makes sense).. So my question is if you guys know of a mean to get, in the parent class, the name of child class.

推荐答案

简而言之.这不可能.在 php4 中，您可以实现一个可怕的 hack(检查 debug_backtrace())，但该方法在 PHP5 中不起作用.参考资料:

in short. this is not possible. in php4 you could implement a terrible hack (examine the debug_backtrace()) but that method does not work in PHP5. references:

• 30423

• 37684

• 34421

edit:PHP 5.3 中后期静态绑定的示例(在评论中提到).请注意，它当前的实施存在潜在问题(src).

edit: an example of late static binding in PHP 5.3 (mentioned in comments). note there are potential problems in it's current implementation (src).

class Base {
    public static function whoAmI() {
        return get_called_class();
    }
}

class User extends Base {}

print Base::whoAmI(); // prints "Base"
print User::whoAmI(); // prints "User"

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