/**

 * @author xiaojiang

 * 方式1

 */

class father{

    static $models = [];

    static public function getInstance(){

        $name =  get_called_class();

        if( !isset( self::$models[$name] ) ){

            self::$models[$name] = new $name();

        }

        return self::$models[$name];

    }

    public function m1(){

        echo "fm1";

    }

    public function m2(){

        echo "fm2";

    }

}

class child extends father{

    public function m1(){

        echo 'cm1';

    }

}

father::getInstance()->m1();

child::getInstance()->m1();

/**

 * 方式2

 */

 class base{

    static protected  $ins = [];

    static public function getInstance(){

        $cName = get_called_class();

        if( !isset(static::$ins[$cName]) ){

            static::$ins[$cName] = new $cName;

        }

        return static::$ins[$cName];

    }

    public function m1(){

        return "base m1";

    }

    public function m2(){

        return "base m2";

    }

}

class cbase extends base{

    //static public $ins = null;

    static public function getInstance(){

        return parent::getInstance();

    }

    public function m1(){

        return "cbase m1<br>";

    }

}

echo base::getInstance()->m1()."<br>";

echo cbase::getInstance()->m1();