design patterns explained simply

Please read the previous article first Refactoring Even the most thoughtful and skilled programmers cannot foresee any nuance in a software project. The problem is always unexpected, the demand may be changing, and the result is that the code is optimized, shared, and replaced. Refactoring is a common approach: check all your code to find the similarities and the similarities in which you can unify and simplify, making your code easier to maintain and extend. Refactoring also involves exploring

passed in, that is to show　　　　　　　　　　Likeeat likeeat = new Endeat (New Eatfoot (New Inrestaurant (New Gotorestaurant (New Findinmap (person)))))The look of this structure. So when calling Likeeat.eat () , and because of each specific decorator class, first call super.eat (); method, and the Super has been passed by the construction and pointed to a specific decorator class (this can be replaced according to the order), then called the Decoration class method, and then call their own decorative m

Definition DesignPattern. The design pattern is used to make code reusable, make it easier for others to understand, and ensureCode reliability. There is no doubt that the design model is a win-win solution for others and the system. The design model enables code compilation to be truly engineered. The design model is

, the subject object itself is passed to the observer through the Update methodSo that when the observer needs to get the data, it can use this reference to get the Comparison of two implementation methods The push model is the assumption that the subject object knows the data that the observer needs;While the pull model is the subject object does not know what the observer specifically needs data, there is no way, simply pass

This "Zen of design patterns" was not easy to get. At that time, I had the honor to ask Qin Xiaobo in the csdn forum. Reading such a classic book cannot be like reading a novel. It is intended to be a pleasure to go around for a long time. It is more about reading and changing questions. Why should we ask every key point. Teacher Qin Xiaobo's language is sometimes humorous and sometimes important. Mr. Qin X

Introduction The reason why the name is "0 of design patterns" is that the simple factory model does not belong to one of 23 gof design patterns. It is determined by a factory object to create a product instance. The simple factory model is the simplest and Practical Model in the factory model family. It can be underst

, simply declaring it, without implementingvar Composite = new Interface (' Composite ', [' Add ', ' Remove ', ' getchild ']);Declaring an interface, simply declaring it, without implementingvar FormItem = new Interface (' FormItem ', [' Save ']);Declaring the implemented classfunction MenuItem (ID, method, action) {...This.show = function (object) {Interface.ensureimplements (This, [Composite, MenuItem]);E

) { This. Payamount =Payamount; } PublicString getmsg () {returnmsg; } Public voidsetmsg (String msg) { This. msg =msg; } PublicPrototype2 Clone ()throwsclonenotsupportedexception {Prototype2 clone= (Prototype2)Super. Clone (); returnclone; }}/*** Created by Wangbin10 on 2018/5/18.*/ Public classPTest { Public Static voidMain (string[] args)throwsclonenotsupportedexception {Prototype2 P1=NewPrototype2 ("Zhangsan", "Hello!welcome to beijing!"); System.out.println (P1.getname ()+p1.get

supports different types of products, more convenient to use the middle of the same family of different types of products. Add a family of products, do not modify the factory class and Product class interface, do not violate the open and closed principle.Cons: The structure is too bloated, even if I simply implement, and 3x2, wrote the above so much code. If the number of product groups becomes greater or the number of families increases, it can be d

whole pattern of using lambda expressions is greatly simplified because we can completely abolish these classes. Let's see if the macro Class (client) uses a lambda expression instead of the command class's effect.Filereceiver.closefile (), new--- Macro.run (); If you can realize that each lambda expression is executing a separate method call, you can further refine it. Therefore, you can use the method reference directly.New Macro (); Macro.record (filereceiver::openfile); Macro.record (filere

: This article mainly introduces the third part of API development: the perfect Singleton mode of PHP design patterns. if you are interested in PHP tutorials, refer to it. Let's talk about the Singleton mode today. I used to develop java. when I used the Singleton mode, I first thought of using the hungry Chinese style. then I found that PHP has the following features: PHP does not support granting non-bas

#-*-Coding:utf-8-*-__author__ = ' Administrator '#python高级编程: A useful design pattern#代理"""Proxies provide a non-direct access mechanism to a costly or remote resourceBetween the customer and the idea,. It is used to optimize access to high-cost topics, such as the memoize adorner described in the previous chapter can be considered a proxy, it can also be used to provide smart access to a topic, for example, large video files can be enclosed in proxie

be implemented with interfaces and implementation classes, and all design patterns are less rigid and can be adapted to specific situations. Factory Method Mode, is the same abstraction of the factory class as the product class, where each plant produces only one product, such as a fighter factory producing fighter jets and passenger aircraft, which inherit abstract aircraft factory classes. Because the

In the 23 design modes of GOF, the singleton mode is a relatively simple one. However, sometimes the simpler things become more prone to problems. The following is a detailed discussion of the single-instance design pattern.The so-called singleton mode, simply put, is to ensure that only one instance of a class exists throughout the application. It is like applic

IOS design patterns-(2) UML inter-class relationships Before formally speaking about the design mode, it is necessary to introduce the relationship between UML class diagrams, because class diagrams will be widely used in some tutorials, books, including my subsequent articles, describes the relationships between classes. This is an intuitive and simple method. O

sources for the data to be presented by the View and supports the business logic for the interactive operations of the View. Ii. Why does Prism use MVVM? The Lightweight Framework Prism enables the development team to focus on business logic development by applying MVVM. the design team focuses on designing friendly interaction interfaces for users. The two teams may be less involved in cross-design develo

In the previous section we explained some of the knowledge of the observer pattern and customized the classic code of the Observer Pattern, (Teleport: Design mode go through--observer mode (above)) This article briefly introduces the observer Pattern implementation code that comes with the JDK. For the Observer pattern, a observer Interface (Viewer), a observable class (Subject object) is provided in the JD

broadcast receives the corresponding broadcast message, which is the typical observer pattern.Let's take a look at some of the observer patterns in the open source framework. When it comes to open source frameworks, the first thing you should think about is eventbus. Yes, Eventbus is also based on the Observer pattern.Three typical methods of the observer pattern it has, that is, register, unregister, send eventEventBus.getDefault().register(Object s

Promises and Design Patterns Well written long good long long ~ The traditional way to solve a Javascript asynchronous event is to call a callback function, invoke a method, then give it a function reference, and execute the function reference when the method ends. $.get (' Api/gizmo/42 ', function (Gizmo) { console.log (gizmo);//or whatever}); It looks great, right, but there are drawbacks; first,

); Where.appendchild (TXT); };};//Child function 2: Working with linksPage.dom.Link =function() { This. Insert =function(where) {varlink = document.createelement (' a '); Link.href = This. URL; Link.appendchild (document.createTextNode ( This. url)); Where.appendchild (link); };};//Child function 3: working with picturesPage.dom.Image =function() { This. Insert =function(where) {varim = document.createelement (' img '); IM.SRC = This. URL; Where.appendchild (IM); };};So how do we define