<?php
date_default_timezone_set("PRC");
/*** 多态* 1. 只要某个对象实现了接口（instanceof），就可以直接在对象上调用接口的方法*/interface ICanEat {public function eat($food);
}// Human类实现了ICanEat接口
class Human implements ICanEat { // 跟Animal类的实现是不同的public function eat($food){echo "Human eating " . $food . "\n";}
}// Animal类实现了ICanEat接口
class Animal implements ICanEat {public function eat($food){echo "Animal eating " . $food . "\n";}
}function eat($obj){if($obj instanceof ICanEat){ $obj->eat("FOOD"); // 不需要知道到底是Human还是Animal，直接吃就行了}else{echo "Can't eat!\n";}
}$man = new Human();
$monkey = new Animal();// 同样的代码，传入接口的不同实现类的时候，表现不同。这就是为什么成为多态的原因。
eat($man);
eat($monkey);?>

<?php
date_default_timezone_set("PRC");
/*** 抽象类* 1. 抽象类允许类里面的部分方法暂时没有具体实现，这些方法我们成为抽象方法* 2. 一旦类里面有抽象方法，这个类就必须是抽象类* 3. 抽象类跟接口一样，不能直接实例化为对象*/// 抽象类前面以abstract关键字开始
abstract class ACanEat {// 没有实现的方法需要设定为抽象方法// 抽象方法需要在子类中实现 abstract public function eat($food);public function breath(){echo "Breath use the air.\n";}
}// Human类实现了ICanEat接口
class Human extends ACanEat { // 跟Animal类的实现是不同的public function eat($food){echo "Human eating " . $food . "\n";}
}// Animal类实现了ICanEat接口
class Animal extends ACanEat {public function eat($food){echo "Animal eating " . $food . "\n";}
}$man = new Human();
$man->eat("Apple");
$man->breath(); // 和Animal共用了抽象类ICanEat的breath方法
$monkey = new Animal();
$monkey->eat("Banana");
$monkey->breath();?>

<?php
date_default_timezone_set("PRC");
/*** 魔术方法1* 1. 当对象被当做String使用时，__tostring()会被自动调用* 2. 当对象被当成方法调用时，__invoke()会被自动调用*/
class MagicTest{public function __tostring(){return "This is the Class MagicTest.\n";}public function __invoke($x){echo "__invoke called with parameter " . $x . "\n";}
}$obj =  new MagicTest();
echo $obj;
$obj(5);  //直接在对象中传入参数5，它会被__invoke()函数接收?>

<?php
date_default_timezone_set("PRC");
/*** 魔术方法2之方法重载* 1. 当对象访问不存在的方法名称时，__call()方法会被自动调用* 2. 当对象访问不存在的静态方法名称时，__callStatic()方法会被自动调用*/
class MagicTest{public function __tostring(){return "This is the Class MagicTest.\n";}public function __invoke($x){echo "__invoke called with parameter " . $x . "\n";}public function __call($name, $arguments){echo "Calling " . $name . " with parameters: " . implode(', ', $arguments) . "\n";}public static function __callStatic($name, $arguments){echo "Static calling " . $name . " with parameters: " . implode(', ', $arguments) . "\n";}
}$obj =  new MagicTest();
$obj->runTest("para1", "para2");
MagicTest::runTest("para3","para4");?>

<?php
date_default_timezone_set("PRC");
/*** 魔术方法3之属性重载* 1. 在给不可访问属性赋值时，__set() 会被调用。* 2. 读取不可访问属性的值时，__get() 会被调用。* 3. 当对不可访问属性调用 isset() 和empty()时，__isset() 会被调用。* 4. 当对不可访问属性调用 unset() 时，__unset() 会被调用*/
class MagicTest{public function __tostring(){return "This is the Class MagicTest.\n";}public function __invoke($x){echo "__invoke called with parameter " . $x . "\n";}public function __call($name, $arguments){echo "Calling " . $name . " with parameters: " . implode(', ', $arguments) . "\n";}public static function __callStatic($name, $arguments){echo "Static calling " . $name . " with parameters: " . implode(', ', $arguments) . "\n";}// 通过这两个方法可以实现动态的对象属性public function __get($name){return "Getting the property " . $name;}public function __set($name, $value){echo "Setting the property " . $name . " to value ". $value. "\n";}public function __isset($name){echo "__isset invoked\n";return false;}public function __unset($name){echo "unsetting property " . $name;}
}$obj =  new MagicTest();
echo $obj->name . "\n";
$obj->name = "Name Value";
echo '$obj->name is set? '. isset($obj->name) . "\n";
echo '$obj->name is empty?' . empty($obj->name) . "\n";
unset($obj->name);
?>