PHP面向对象核心：抽象类、接口与instanceof用法解析

abstract class AbstractClass {
    // 抽象方法：仅保留签名，无具体实现
    abstract public function prototypeName($protoParam);
}

<?php
// 定义抽象基类：Car
abstract class Car {
    // 声明抽象方法，强制子类实现获取最高速度的逻辑
    abstract function getMaxSpeend();
}

// 实现类 Roadster
class Roadster extends Car {
    public $Speend;
    
    public function SetSpeend($speend = 0) {
        $this->Speend = $speend;
    }
    
    // 实现抽象方法
    public function getMaxSpeend() {
        return $this->Speend;
    }
}

// 业务逻辑类：街道规则
class Street {
    public $Cars = array();
    public $SpeedLimit;
    
    function __construct( $speedLimit = 200) {
        $this-> SpeedLimit = $speedLimit;
    }
    
    protected function IsStreetLegal($car) {
        if ($car->getMaxSpeend() < $this -> SpeedLimit) {
            return true;
        } else {
            return false;
        }
    }
    
    public function AddCar($car) {
        if($this->IsStreetLegal($car)) {
            echo 'The Car was allowed on the road.';
            $this->Cars[] = $car;
        } else {
            echo 'The Car is too fast and was not allowed on the road.';
        }
    }
}

// 测试用例
$Porsche911 = new Roadster();
$Porsche911->SetSpeend(340); // 设定极速340
$FuWaiStreet = new Street(80); // 设定限速80
$FuWaiStreet->AddCar($Porsche911);
// 输出结果: The Car is too fast and was not allowed on the road.
?>

<?php
abstract class Car {
    abstract function SetSpeend($speend = 0);
}

// 定义接口
interface ISpeedInfo {
    function GetMaxSpeend();
}

// 同时继承抽象类和实现接口
class Roadster extends Car implements ISpeedInfo {
    public $Speend;
    
    public function SetSpeend($speend = 0) {
        $this->Speend = $speend;
    }
    
    // 必须实现接口和抽象类的所有方法
    public function GetMaxSpeend() {
        return $this->Speend;
    }
}

// ... (Street 类定义同上) ...

$Porsche911 = new Roadster();
$Porsche911->SetSpeend(340);
$FuWaiStreet = new Street(80);
$FuWaiStreet->AddCar($Porsche911);
// 输出结果: The Car is too fast and was not allowed on the road.
?>

// 检查是否为 Car 的实例（包括其子类）
echo $Porsche911 instanceof Car;   // 输出：1 (true)

// 检查是否实现了 ISpeedInfo 接口
echo $Porsche911 instanceof ISpeedInfo; // 输出：1 (true)