In the previous article "Let’s talk about the memo mode in PHP" we introduced the memo mode in PHP. The following article will take you to understand the bridge mode in PHP design pattern.
Bridge mode, in the programming world, is actually synonymous with combination/aggregation. Why do you say that? We who are familiar with object-oriented all know the benefits of inheritance. Subclasses can share many attributes and functions of the parent class. However, inheritance also brings a problem, that is, serious coupling. Modifications of the parent class will have an impact on subclasses to some extent. Even a modification of a method or attribute may require all subclasses to modify it. This violates the principle of open encapsulation. Bridging is to solve this problem. It emphasizes the use of combination/aggregation to share some available methods. I believe you must have thought of traits in PHP. If you have used this feature at work, then you have already used bridge mode!
GoF definition: Separate the abstract part from its implementation part so that they can change independently.
GoF class diagram
##Code implementation
interface Implementor { public function OperationImp(); } class ConcreteImplementorA implements Implementor { public function OperationImp() { echo '具体实现A', PHP_EOL; } } class ConcreteImplementorB implements Implementor { public function OperationImp() { echo '具体实现B', PHP_EOL; } }
abstract class Abstraction { protected $imp; public function SetImplementor(Implementor $imp) { $this->imp = $imp; } abstract public function Operation(); } class RefinedAbstraction extends Abstraction { public function Operation() { $this->imp->OperationImp(); } }
$impA = new ConcreteImplementorA(); $impB = new ConcreteImplementorB(); $ra = new RefinedAbstraction(); $ra->SetImplementor($impA); $ra->Operation(); $ra->SetImplementor($impB); $ra->Operation();
Our mobile phones have different models, and each model produces roughly the same but different accessories. For example, X1 mobile phone case, film, and earphones; X2 mobile phone case, film, and earphones, etc. Due to cost issues, we will not produce completely different accessories for each model of mobile phone. Instead, try to use external universal accessories (Implementor), so that each model of mobile phone (Abstraction) can be combined (Bridge) and sold to consumers. In this way, our mobile phone brand will not run out of financing and close down too early. It seems that there are really many correlations between running a business and learning design patterns! !
Full code: https://github.com/zhangyue0503/designpatterns-php/blob/master/18.bridge/source/bridge.php
SMS sending class diagram
Full source code: https://github.com/zhangyue0503/designpatterns-php /blob/master/18.bridge/source/bridge-message.php<?php interface MessageTemplate { public function GetTemplate(); } class LoginMessage implements MessageTemplate { public function GetTemplate() { echo '您的登录验证码是【AAA】,请不要泄露给他人【XXX公司】!', PHP_EOL; } } class RegisterMessage implements MessageTemplate { public function GetTemplate() { echo '您的注册验证码是【BBB】,请不要泄露给他人【XXX公司】!', PHP_EOL; } } class FindPasswordMessage implements MessageTemplate { public function GetTemplate() { echo '您的找回密码验证码是【CCC】,请不要泄露给他人【XXX公司】!', PHP_EOL; } } abstract class MessageService { protected $template; public function SetTemplate($template) { $this->template = $template; } abstract public function Send(); } class AliYunService extends MessageService { public function Send() { echo '阿里云开始发送短信:'; $this->template->GetTemplate(); } } class JiGuangService extends MessageService { public function Send() { echo '极光开始发送短信:'; $this->template->GetTemplate(); } } // 三个短信模板 $loginTemplate = new LoginMessage(); $registerTemplate = new RegisterMessage(); $findPwTemplate = new FindPasswordMessage(); // 两个短信服务商 $aliYun = new AliYunService(); $jg = new JiGuangService(); // 随意组合 // 极光发注册短信 $jg->SetTemplate($registerTemplate); $jg->Send(); // 阿里云发登录短信 $aliYun->SetTemplate($loginTemplate); $aliYun->Send(); // 阿里云发找回密码短信 $aliYun->SetTemplate($findPwTemplate); $aliYun->Send(); // 极光发登录短信 $jg->SetTemplate($loginTemplate); $jg->Send(); // ......Copy after loginExplanation
This is an aggregation mode. Templates are not part of SMS sending. We can send them directly without using templates. They have no strong relationship.
- The SMS sending method does not need to be changed. You only need to pass in different SMS templates to implement various templates. Quickly send
- When you are not sure whether it must be an is-a relationship, it is more recommended to use a combination/aggregation design method such as bridge mode. If it is determined that the current class relationship is is-a, Then don’t hesitate to use inheritance
Original address: https://juejin.cn/post/6844903986655395848Author: Hardcore Project ManagerRecommended learning: "PHP Video Tutorial"
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