<?php
/**
* Observer mode application scenario example
*
* Disclaimer: This article is just an example of Harpiao.com. The example does not involve any business code of Harpiao.com. All are original. If there is any similarity, it is purely coincidental.
*
* Scene description:
* Ha Ticket Purchase as its core business(This model is not limited to this service), but different other logics will be generated around ticket purchase, such as:
* 1, record text log after purchasing tickets
* 2, record the database log after purchasing tickets
* 3, Send text messages after purchasing tickets
* 4, buy tickets and get deductions, redemptions, points
* 5, other activities, etc.
*
* Traditional solutions:
* Add relevant codes to categories such as ticket purchase logic to complete various logics.
*
* There are problems:
* 1, Once a certain business logic changes, such as adding other business logic to the ticket purchase business, the core documents of ticket purchase and even the ticket purchase process need to be modified.
* 2, After years of accumulation, the documents are lengthy, resulting in difficulty in subsequent maintenance.
*
* The main reason for the problem is the program"Tightly coupled", use the observation mode to optimize the current business logic into"Loose coupling", achieve the purpose of easy maintenance and modification,
* It also conforms to the idea of interface-oriented programming.
*
* Typical implementation of observer mode:
* 1,definition2Each interface: observer (notification) interface, observer (theme) interface
* 2,definition2Class, observer object realizes the observer interface, subject class realizes the observer interface
* 3, Theme registration category to register the observer you need to notify
* 4, When a certain business logic of the subject occurs, notify the observer object, and each observer executes his or her own business logic.
*
* Example: As shown in the following code
*
*/
#===================Define the observer, the observer interface============
/**
*
* Observer interface(Notification interface)
*
*/
interface ITicketObserver //Observer interface
{
function onBuyTicketOver($sender, $args); //Methods called after getting notification
}
/**
*
* Theme interface
*
*/
interface ITicketObservable //The interface to be observed
{
function addObserver($observer); //Provide a method of registering an observer
}
#====================Theme class implementation========================
/**
*
* Topic category (ticket purchase)
*
*/
class HipiaoBuy implements ITicketObservable { //Implement the topic interface (observed)
private $_observers = array (); //Notification array (observer)
public function buyTicket($ticket) //Ticket purchase core category, handling ticket purchase process
{
// TODO Ticket purchase logic
//Loop notification, call itonBuyTicketOverImplement different business logic
foreach ( $this->_observers as $obs )
$obs->onBuyTicketOver ( $this, $ticket ); //$this Can be used to get the topic class handle, and use it in notifications
}
//Add notification
public function addObserver($observer) //Add toNA notice
{
$this->_observers [] = $observer;
}
}
#=========================Define multiple notifications====================
//SMS log notification
class HipiaoMSM implements ITicketObserver {
public function onBuyTicketOver($sender, $ticket) {
echo (date ( 'Y-m-d H:i:s' ) . " SMS logging: ticket purchase is successful:$ticket<br>");
}
}
//Text log notification
class HipiaoTxt implements ITicketObserver {
public function onBuyTicketOver($sender, $ticket) {
echo (date ( 'Y-m-d H:i:s' ) . " Text logging: ticket purchase successful:$ticket<br>");
}
}
//Deduction bill gift notice
class HipiaoDiKou implements ITicketObserver {
public function onBuyTicketOver($sender, $ticket) {
echo (date ( 'Y-m-d H:i:s' ) . " Gift deduction ticket: successful ticket purchase:$ticket Gift10Yuan deduction volume1open.<br>");
}
}
#============================Users purchase tickets====================
$buy = new HipiaoBuy ();
$buy->addObserver ( new HipiaoMSM () ); //Add various notifications according to different business logic
$buy->addObserver ( new HipiaoTxt () );
$buy->addObserver ( new HipiaoDiKou () );
//Purchase tickets
$buy->buyTicket ( "One row and one number" );
?>
Copyright: Robot_G(swengineer) Welcome to reprint/swengineer/archive/2011/03/22/