php回调函数

<?php 
// An example callback function
function my_callback_function() {
    echo 'hello world!';
}
// An example callback method
class MyClass {
    static function myCallbackMethod() {
        echo 'Hello World!';
    }
}
// Type 1: Simple callback
//普通的全局方法
call_user_func('my_callback_function'); 
// Type 2: Static class method call
//静态方法调用，这时候传入的是一个数组
call_user_func(array('MyClass', 'myCallbackMethod')); 
// Type 3: Object method call
//对象的方法，这时候传入的是一个数组
$obj = new MyClass();
call_user_func(array($obj, 'myCallbackMethod'));
// Type 4: Static class method call (As of PHP 5.2.3)
//以字符串的形式传入静态方法
call_user_func('MyClass::myCallbackMethod');
// Type 5: Relative static class method call (As of PHP 5.3.0)
//父类的普通方法
class A {
    public static function who() {
        echo "A\n";
    }
}
class B extends A {
    public static function who() {
        echo "B\n";
    }
}
call_user_func(array('B', 'parent::who')); // A
//Type 6: Our closure
//闭包或者说匿名方法
$double = function($a) {
    return $a * 2;
};
// This is our range of numbers
$numbers = range(1, 5);
// Use the closure as a callback here to 
// double the size of each element in our 
// range
$new_numbers = array_map($double, $numbers);
print implode(' ', $new_numbers);
?>

<?php
class MyClass {
    public $property = 'Hello World!';
    public function MyMethod(){
        call_user_func(array($this, 'myCallbackMethod'));
    }
    public function MyCallbackMethod(){
        echo $this->property;
    }
}
?>