PHP中如何使用抽象类和接口来管理和操作自定义数据类型

<?php

// 定义抽象类Animal
abstract class Animal {
    protected $name;
    protected $age;
    
    public function __construct($name, $age) {
        $this->name = $name;
        $this->age = $age;
    }
    
    abstract public function say();
}

// 定义接口AnimalInterface
interface AnimalInterface {
    public function run();
    public function sleep();
}

// 子类Cat继承Animal类，并实现AnimalInterface接口
class Cat extends Animal implements AnimalInterface {
    public function say() {
        echo "I am a cat.
";
    }
    
    public function run() {
        echo "Cat is running.
";
    }
    
    public function sleep() {
        echo "Cat is sleeping.
";
    }
}

// 子类Dog继承Animal类，并实现AnimalInterface接口
class Dog extends Animal implements AnimalInterface {
    public function say() {
        echo "I am a dog.
";
    }
    
    public function run() {
        echo "Dog is running.
";
    }
    
    public function sleep() {
        echo "Dog is sleeping.
";
    }
}

$cat = new Cat("Tom", 3);
$cat->say();
$cat->run();
$cat->sleep();

$dog = new Dog("Hank", 5);
$dog->say();
$dog->run();
$dog->sleep();

?>