PHP Design Pattern Series - Observer Pattern_PHP Tutorial

Observer Mode
The Observer design pattern makes it easier to create and view objects that target object status, and provides top-level functionality that is decoupled from core objects. The observer design pattern is very commonly used. In generally complex WEB systems, the observer pattern can help you reduce the pressure of code design and reduce code coupling.
Scene design
Design an order class
After the order is created, various actions will be performed, such as sending EMAIL, or changing the order status, etc.
The original method is to write all these operations in the create function
However, as the order creation class becomes larger and larger, such operations can no longer meet the demand and rapid changes
At this time, the observer mode appears.
Code design:
[php]
//The observer design pattern makes it easier to create and view objects with target object status, and provides top functionality that is uncoupled from core objects.
//The observer design pattern is very commonly used. In generally complex WEB systems, the observer pattern can help you reduce the pressure of code design and reduce code coupling.
//Take a shopping process as an example
class order {

Protected $observers = array(); // Store observation container
       
//Added observer
Public function addObServer($type, $observer) {
          $this->observers[$type][] = $observer;
}  
       
//Run observer
Public function obServer($type) {
If (isset($this->observers[$type])) {
foreach ($this->observers[$type] as $obser) {
                     $a = new $obser;
                                                 $a->update($this); //Public method
                                                                                                                                               } 
}  
       
//Order purchase process
Public function create() {
echo 'Purchase successful';
           $this->obServer('buy'); // buy action
}  
}
class orderEmail {
Public static function update($order) {
echo 'Send a successful purchase email';
}  
}
class orderStatus {
Public static function update($order) {
           echo 'Change order status';
}  
}
$ob = new order;
$ob->addObServer('buy', 'orderEmail');
$ob->addObServer('buy', 'orderStatus');
$ob->create();
Author: initphp

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