Command mode and design of go redis command

itread01 2021-01-22 13:59:39
command mode design redis command


[TOC]#### One 、 What is an order (Command) Pattern command pattern is a kind of behavioral design pattern , The purpose is to encapsulate a request as an object , So that you can parameterize customers with different requests . Compared to another way of combining each command with the object calling the command to form a proprietary class , The advantage of command mode is that it decouples the object calling the operation from the object knowing how to implement the operation , Adding new commands does not require modifying existing classes . The structure of the command mode is as follows :![command](https://img2020.cnblogs.com/blog/1447810/202101/1447810-20210122095641252-470394572.png) The participants are :1.Invoker The requester asks the command to execute the request , The caller of the order 2.Command Interface 3.ConcreteCommand Specific interfaces 4.Receiver The actual implementer of the operation related to the receiver's command 5.Client Collaborative process :1.Client Build a ConcreteCommand Object and specify its Receiver thing 2. some Invoker The object stores the ConcreteCommand thing 3. The Invoker By calling Command Of objects Excute Operation to submit a request . If the command is revocable ,ConcreteCommand It's just executing Excute Save the current state before operation to cancel the command 4.ConcreteCommand The object calls its Receiver To perform the request #### Two 、go-redis command Related code ```// commands.go// Invoker Requester interface type Cmdable interface { Pipeline() Pipeliner Pipelined(ctx context.Context, fn func(Pipeliner) error) ([]Cmder, error) TxPipelined(ctx context.Context, fn func(Pipeliner) error) ([]Cmder, error) TxPipeline() Pipeliner Command(ctx context.Context) *CommandsInfoCmd ClientGetName(ctx context.Context) *StringCmd // ... // And all Redis Command related methods }// cmdable Achieved Cmdable Interface type cmdable func(ctx context.Context, cmd Cmder) error func (c cmdable) Echo(ctx context.Context, message interface{}) *StringCmd { cmd := NewStringCmd(ctx, "echo", message) _ = c(ctx, cmd) return cmd}``` What is worth mentioning here is cmdable Is a function type ,func(ctx context.Context, cmd Cmder) error And every one of them cmdable There will be in every way _ = c(ctx, cmd), That's how to call cmd I haven't written it clearly yet. Let's look back redis.go, You'll find this piece of code ```type Client struct { *baseClient cmdable hooks ctx context.Context}func NewClient(opt *Options) *Client { opt.init() c := Client{ baseClient: newBaseClient(opt, newConnPool(opt)), ctx: context.Background(), } c.cmdable = c.Process // scribing return &c}```c.cmdable = c.Process This line specifies how the request calls Command The in ctrl+ Left click to track several layers , Will be in redis.go Find the specific process of the call in ```// redis.go func (c *baseClient) process(ctx context.Context, cmd Cmder) error { ...... err := cn.WithWriter(ctx, c.opt.WriteTimeout, func(wr *proto.Writer) error { eturn writeCmd(wr, cmd) }) err = cn.WithReader(ctx, c.cmdTimeout(cmd), cmd.readReply) ...... ``` And then go to Command, This is clearer , All in command.go in ```// command.go// Command Interface type Cmder interface { Name() string FullName() string Args() []interface{} String() string stringArg(int) string firstKeyPos() int8 setFirstKeyPos(int8) readTimeout() *time.Duration readReply(rd *proto.Reader) error SetErr(error) Err() error}// There are many more Cmder The concrete realization of , Part of the code for one of the implementations is as follows type XPendingExtCmd struct { baseCmd val []XPendingExt}func (cmd *XPendingExtCmd) Val() []XPendingExt { return cmd.val}``` I don't see it here Receiver, Because of every Cmder All the functions are realized by themselves , There's no need for additional recipient objects at all .#### 3、 ... and 、 Summary sometimes you have to submit a request to something , But do not know any information about the requested operation or the recipient of the request . You can use command mode at this time , By turning the request itself into an object, the toolbox object can make a request to an unspecified application object
版权声明
本文为[itread01]所创,转载请带上原文链接,感谢
https://javamana.com/2021/01/20210122135316729r.html

  1. 【计算机网络 12(1),尚学堂马士兵Java视频教程
  2. 【程序猿历程,史上最全的Java面试题集锦在这里
  3. 【程序猿历程(1),Javaweb视频教程百度云
  4. Notes on MySQL 45 lectures (1-7)
  5. [computer network 12 (1), Shang Xuetang Ma soldier java video tutorial
  6. The most complete collection of Java interview questions in history is here
  7. [process of program ape (1), JavaWeb video tutorial, baidu cloud
  8. Notes on MySQL 45 lectures (1-7)
  9. 精进 Spring Boot 03:Spring Boot 的配置文件和配置管理,以及用三种方式读取配置文件
  10. Refined spring boot 03: spring boot configuration files and configuration management, and reading configuration files in three ways
  11. 精进 Spring Boot 03:Spring Boot 的配置文件和配置管理,以及用三种方式读取配置文件
  12. Refined spring boot 03: spring boot configuration files and configuration management, and reading configuration files in three ways
  13. 【递归,Java传智播客笔记
  14. [recursion, Java intelligence podcast notes
  15. [adhere to painting for 386 days] the beginning of spring of 24 solar terms
  16. K8S系列第八篇(Service、EndPoints以及高可用kubeadm部署)
  17. K8s Series Part 8 (service, endpoints and high availability kubeadm deployment)
  18. 【重识 HTML (3),350道Java面试真题分享
  19. 【重识 HTML (2),Java并发编程必会的多线程你竟然还不会
  20. 【重识 HTML (1),二本Java小菜鸟4面字节跳动被秒成渣渣
  21. [re recognize HTML (3) and share 350 real Java interview questions
  22. [re recognize HTML (2). Multithreading is a must for Java Concurrent Programming. How dare you not
  23. [re recognize HTML (1), two Java rookies' 4-sided bytes beat and become slag in seconds
  24. 造轮子系列之RPC 1:如何从零开始开发RPC框架
  25. RPC 1: how to develop RPC framework from scratch
  26. 造轮子系列之RPC 1:如何从零开始开发RPC框架
  27. RPC 1: how to develop RPC framework from scratch
  28. 一次性捋清楚吧,对乱糟糟的,Spring事务扩展机制
  29. 一文彻底弄懂如何选择抽象类还是接口,连续四年百度Java岗必问面试题
  30. Redis常用命令
  31. 一双拖鞋引发的血案,狂神说Java系列笔记
  32. 一、mysql基础安装
  33. 一位程序员的独白:尽管我一生坎坷,Java框架面试基础
  34. Clear it all at once. For the messy, spring transaction extension mechanism
  35. A thorough understanding of how to choose abstract classes or interfaces, baidu Java post must ask interview questions for four consecutive years
  36. Redis common commands
  37. A pair of slippers triggered the murder, crazy God said java series notes
  38. 1、 MySQL basic installation
  39. Monologue of a programmer: despite my ups and downs in my life, Java framework is the foundation of interview
  40. 【大厂面试】三面三问Spring循环依赖,请一定要把这篇看完(建议收藏)
  41. 一线互联网企业中,springboot入门项目
  42. 一篇文带你入门SSM框架Spring开发,帮你快速拿Offer
  43. 【面试资料】Java全集、微服务、大数据、数据结构与算法、机器学习知识最全总结,283页pdf
  44. 【leetcode刷题】24.数组中重复的数字——Java版
  45. 【leetcode刷题】23.对称二叉树——Java版
  46. 【leetcode刷题】22.二叉树的中序遍历——Java版
  47. 【leetcode刷题】21.三数之和——Java版
  48. 【leetcode刷题】20.最长回文子串——Java版
  49. 【leetcode刷题】19.回文链表——Java版
  50. 【leetcode刷题】18.反转链表——Java版
  51. 【leetcode刷题】17.相交链表——Java&python版
  52. 【leetcode刷题】16.环形链表——Java版
  53. 【leetcode刷题】15.汉明距离——Java版
  54. 【leetcode刷题】14.找到所有数组中消失的数字——Java版
  55. 【leetcode刷题】13.比特位计数——Java版
  56. oracle控制用户权限命令
  57. 三年Java开发,继阿里,鲁班二期Java架构师
  58. Oracle必须要启动的服务
  59. 万字长文!深入剖析HashMap,Java基础笔试题大全带答案
  60. 一问Kafka就心慌?我却凭着这份,图灵学院vip课程百度云