我知道你有些人会假设接口或抽象,但这只能处理一些情况.这是他们打破的一个例子.
假设我们有类实现相同的接口并扩展相同的基础
class car extends fourwheeler implements ipaygas{
protected $tank1;
//interface
public function payGas($amount){}
}
class sportscar extends fourwheeler implements ipaygas{
protected $tank1;
protected $tank2;
//interface
public function payGas($amount){}
}
interface ipaygas{
function payGas($amount);
}
在某些情况下,您只需要一个界面,因为您可能只想执行’payGas()’.但是当你有条件要做时,你会怎么做.
例如,如果 – 在支付燃气之前,您需要(1)检查汽车类型,(2)使用跑车的优质汽油,以及(3)填充跑车的第二个油箱.
这是我想要做的但是不能做到的
function pumpAndPay(iPayGas $car){
if(gettype($car) == "car"){
fillTank($car,(car) $car->tank1);
}else{
fillTank($car,(sportscar) $car->tank1);
fillTank($car,(sportscar) $car->tank2);
}
}
我怎么能用真正的类型铸造呢?在PHP中有可能吗?
更新(根据回复):
在我的’真实’案例中……想象一下我必须检查各种车型,每种车型都有不同的油漆,车身,内饰,gas_type,cleaner_type,颜色等……
abstract class AVechicle{}
abstract class ACar extends AVechicle{}
abstract class ATruckOrSUV extends AVechicle{}
abstract class ABike extends AVechicle{}
class Car extends ACar{}
class SportsCar extends ACar{}
class SUV extends ATruckOrSUV{}
class Truck extends ATruckOrSUV{}
class Bike extends ABike{}
class Scooter extends ABike{}
class Gasstation{
public function cleanVehicle(AVehicle $car){
//assume we need to check the car type to kNow
//what type of cleaner to use and how to clean the car
//if the car has leather or bucket seats
//imagine we have to add an extra $2/h for sports cars
//imagine a truck needs special treatment tires
//or needs inspection
}
public function pumpAndPay(AVehicle $car){
//need to kNow vehicle type to get gas type
//maybe we have a special for scooters only, Green Air campaign etc.
}
public function fullService(AVehicle $car){
//need to kNow if its a truck to do inspection FirsT
$this->cleanVehicle($car);
$this->pumpAndPay($car);
//bikes get 10% off
//cars get free carwash
}
}
接口和摘要本身只会到目前为止……
解决方法:
简短回答你的问题,不,你不能将对象重铸到另一个对象.
然而,Dan Lee的反应非常好,接近我的建议.为什么不将fillTank作为车辆对象的属性,这样扩展车辆类的所有对象都将知道如何填充自己的坦克.像这样的东西:
abstract class Vehicle
{
protected $tank1;
protected $tank2;
// Declaring an abstract function in parent class forces all child class to
// implement same class
abstract public function fillGas() {}
}
class Car extends Vehicle
{
public function fillGas()
{
$this->tank1 = 'full';
}
}
class SportsCar extends Vehicle
{
public function fillGas()
{
$this->tank1 = 'full';
$this->tank2 = 'full';
}
}
class Skateboard extends Vehicle
{
// Skateboards don't have gastanks, just here to sastify parent abstract deFinition
public function fillGas() {}
}
当然,你的OP的一个大谬论就是你假设所有的跑车都有两个油箱,而事实并非如此.只有某些跑车有多个油箱.
另一种方法是看一下特征(available as of PHP 5.4).看起来您可以强制实现接口以及跨不扩展同一类的对象的实现.
– 更新 –
Update (Based on responses): In my ‘real’ case… imagine I have to check varIoUs Vehicle types, each with different paint, body, interior, gas_type, cleaner_type, color, etc…
你提到的所有这些属性都是车辆属性,而不是gastation,fillstation,parkinglot等属性,因此我会将所有这些属性添加到车辆类中,然后你可以将车辆传递给Gasstation :: cleanVehicle()工厂方法来操纵车辆属性.
下面的代码片段仅为DEMONSTRATIVE,演示了如何将上述属性附加到车辆类别,以及Gasstation类如何根据车辆类别操纵车辆属性.我在5分钟内编写了以下内容,但显然需要更多考虑正确处理工厂方法以及是否传递给其他对象等.请考虑以下内容:
abstract class Vehicle
{
// Setting these to public for demonstration only, otherwise you should set these
// to protected and write public accessors
public $paintType;
public $bodyType;
public $interior;
}
class Car extends Vehicle
{
}
class Suv extends Vehicle
{
}
class Truck extends Vehicle
{
}
class Gasstation
{
public static function cleanVehicle(Vehicle $vehicle)
{
switch (get_class($vehicle)) {
case 'Car':
// Car specific cleaning
break;
case 'Truck':
// Truck specific cleaning
break;
default:
throw new Exception(sprintf('Invalid $vehicle: %s', serialize($vehicle)));
}
// We've gone through our vehicle specific cleaning, Now we can do generic
if ('Leather' === $vehicle->getInterior()) {
// Leather specific cleaning
}
if ('Sedan' === $vehicle->getBodyType()) {
// Sedan specific cleaning
}
}
}
$car = new Car();
$car->setPaintType = 'Glossy';
$car->setBodyType = 'Sedan';
$car->setInterior = 'Cloth';
$suv = new Suv();
$suv->setPaintType = 'Glossy';
$suv->setBodyType = 'Crossover';
$suv->setInterior = 'Leather';
$truck = new Truck();
$truck->setPaintType = 'Flat';
$truck->setBodyType = 'ClubCab';
$truck->setInterior = 'Cloth';
$vehicles = array($car, $suv, $truck);
foreach ($vehicles as $vehicle) {
Gasstation::cleanVehicle($vehicle);
}
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