PHP外观模式

Question

我试图学习Facade模式，但遇到了一个问题。PHP不能从PrintPrice方法输出$totalprice。另外，还有其他信息:初始化后的var_dump和object提供给我的：

private 'SkiRent' => 
object(SkiRent)[2]
private 'SkiResortTicketSystem' => 
object(SkiResortTicketSystem)[3]
private 'HotelBookingSystem' => 
object(HotelBookingSystem)[4]
private 'totalprice' => null

但是在调用HaveGoodRest之后，var_dump给了我一个空白页面。我想知道你是否可以帮助我，这是代码：

<?php
class SkiRent
{
public function RentBoots($feetSize, $skierLevel)
{
    return 20*$skierLevel*100/$feetSize;
}
public function RentSki($weight, $skierLevel)
{
    return 40*$skierLevel*100/$weight;
}
public function RentPole($height)
{
    return 5*$height/100;
}
};

class SkiResortTicketSystem
{
public function BuyOneDayTicket()
{
    return 115;
}
public function BuyHalfDayTicket()
{
    return 60;
}
};

class HotelBookingSystem
{
public function BookRoom($roomQuality)
{
    switch ($roomQuality)
    {
        case 3:
            return 250;
        case 4:
            return 500;
        case 5:
            return 900;
        default:
            throw new ArgumentException("roomQuality should be in [3;5]");       
    }

    }
};

class SkiResortFacade
{
private $SkiRent;
private $SkiResortTicketSystem;
private $HotelBookingSystem;
private $totalprice;

function __construct()
{
  $this->SkiRent = new SkiRent(); 
  $this->SkiResortTicketSystem = new SkiResortTicketSystem();
  $this->HotelBookingSystem  = new HotelBookingSystem();
}

function HaveGoodRest($height, $weight, $feetSize, $skierLevel, $roomQuality)
{
    $skiPrice = $SkiRent->RentSki($weight, $skierLevel);
    var_dump($skiPrice);
    $skiBootsPrice = $SkiRent->RentBoots($feetSize,$skierLevel);
    $polePrice = $SkiRent->RentPole($height);
    $oneDayTicketPr = $SkiResortTicketSystem->BuyOneDayTicket();
    $hotelPrice = $HotelBookingSystem->BookRoom($roomQuality);

    $this->totalprice = $skiPrice + $skiBootsPrice + $polePrice + $oneDayTicketPr + $hotelPrice;
}

public function HaveRestWithOwnSkis($roomQuality)
{
    $oneDayTicketPr = $SkiResortTicketSystem->BuyOneDayTicket();
    $hotelPrice = $HotelBookingSystem->BookRoom($roomQuality);
    return $oneDayTicketPr + $hotelPrice;
}

public function PrintPrice()
{
    echo $this->totalprice;
}

};

$rest = new SkiResortFacade();
var_dump($rest);
$height = 181.5;
$weight = 70.1;
$feetSize = 45.2;
$skierLevel = 1.2;
$roomQuality = 3;
$rest->HaveGoodRest($height, $weight, $feetSize, $skierLevel, $roomQuality);
var_dump($rest);
$rest->PrintPrice();
?>

Answer 1

您已经在SkiResortFacade类中定义了$this->SkiRent属性：

$this->SkiRent = new SkiRent(); 

但是您已经在没有$this的情况下引用它：

$skiPrice = $SkiRent->RentSki($weight, $skierLevel);  

它应该是：

$skiPrice = $this->SkiRent->RentSki($weight, $skierLevel);

这是一个正常工作的代码，因此您可以与您的版本进行比较：

<?php
class SkiRent
{
public function RentBoots($feetSize, $skierLevel)
{
    return 20*$skierLevel*100/$feetSize;
}
public function RentSki($weight, $skierLevel)
{
    return 40*$skierLevel*100/$weight;
}
public function RentPole($height)
{
    return 5*$height/100;
}
};

class SkiResortTicketSystem
{
public function BuyOneDayTicket()
{
    return 115;
}
public function BuyHalfDayTicket()
{
    return 60;
}
};

class HotelBookingSystem
{
public function BookRoom($roomQuality)
{
    switch ($roomQuality)
    {
        case 3:
            return 250;
        case 4:
            return 500;
        case 5:
            return 900;
        default:
            throw new ArgumentException("roomQuality should be in [3;5]");       
    }

    }
};

class SkiResortFacade
{
private $SkiRent;
private $SkiResortTicketSystem;
private $HotelBookingSystem;
private $totalprice;

function __construct()
{
  $this->SkiRent = new SkiRent(); 
  $this->SkiResortTicketSystem = new SkiResortTicketSystem();
  $this->HotelBookingSystem  = new HotelBookingSystem();
}

function HaveGoodRest($height, $weight, $feetSize, $skierLevel, $roomQuality)
{
    $skiPrice = $this->SkiRent->RentSki($weight, $skierLevel);
    var_dump($skiPrice);
    $skiBootsPrice = $this->SkiRent->RentBoots($feetSize,$skierLevel);
    $polePrice = $this->SkiRent->RentPole($height);
    $oneDayTicketPr = $this->SkiResortTicketSystem->BuyOneDayTicket();
    $hotelPrice = $this->HotelBookingSystem->BookRoom($roomQuality);

    $this->totalprice = $skiPrice + $skiBootsPrice + $polePrice + $oneDayTicketPr + $hotelPrice;
}

public function HaveRestWithOwnSkis($roomQuality)
{
    $oneDayTicketPr = $SkiResortTicketSystem->BuyOneDayTicket();
    $hotelPrice = $HotelBookingSystem->BookRoom($roomQuality);
    return $oneDayTicketPr + $hotelPrice;
}

public function PrintPrice()
{
    echo $this->totalprice;
}

};

$rest = new SkiResortFacade();
$height = 181.5;
$weight = 70.1;
$feetSize = 45.2;
$skierLevel = 1.2;
$roomQuality = 3;
$rest->HaveGoodRest($height, $weight, $feetSize, $skierLevel, $roomQuality);
$rest->PrintPrice();

Answer 2

致命错误:在第65行对非对象调用成员函数RentSki()

$skiPrice = $SkiRent->RentSki($weight, $skierLevel); // Line 65

$SkiRent不是对象，因为您尚未在HaveGoodRest()方法中实例化它或将其作为参数传入

您的代码中有多个对被操作的非对象的调用。