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This article analyzes "there are too many if else in the project how to restructure". The content is detailed and easy to understand, and friends who are interested in "there are too many if else in the project how to restructure" can follow the editor's train of thought to read it in depth. I hope it will be helpful to you after reading. Let's follow the editor to learn more about "there are too many if else in the project how to restructure".

Preface

If there is too much if else, the strategy mode is generally used for refactoring, and the strategy mode is also very simple. First, define an interface, various processing branches implement this interface, define the mapping relationship of the condition-> processing class, and then find the processing class of the response according to the condition to execute. When there is a new branch, you only need to add an interface implementation class. Add a condition-> mapping relationship of the mapping class. It's still good and easy to understand.

Introduction

Not surprisingly, this should be the last time I shared it a year ago. Here are some tips that will be used in actual development.

For example, do people usually write code like this:

It's good to have few conditions, but once there are too many else if, the logic here will be confused and easy to make mistakes.

Like this:

Extracted from the judgment condition of a client command in cim.

At the beginning, there were fewer conditions, so I didn't care about so many things written directly; now there are so many functions that I have to check carefully every time I add an else condition, for fear of affecting the previous logic.

This time I finally couldn't bear to reconstruct him. After the refactoring, the structure here is as follows:

In the end, it is directly changed into two lines of code, which is much simpler.

All the previous implementation logic is extracted separately into other implementation classes.

So whenever I need to add a new else logic, I only need to add a new class to implement the same interface. Each processing logic is independent and does not interfere with each other.

Realize

A sketch is drawn according to the current implementation.

The overall idea is as follows:

Define an InnerCommand interface in which a process function is given to the specific business implementation.

Depending on your business, there are multiple classes that implement the InnerCommand interface; these implementation classes are registered in the Spring Bean container for later use.

Get an instance of InnerCommand from the Spring Bean container by entering a command from the client.

Execute the final process function.

The main purpose to achieve is not to have multiple judgment conditions, but to dynamically obtain InnerCommand instances according to the status of the current client.

From the point of view of the source code, the most important thing is the InnerCommandContext class, which dynamically acquires the InnerCommand instance according to the current client command.

The first step is to get a list of all the InnerCommand instances.

Get the class type from the list of instances in the first step according to the command entered by the client.

Get the concrete instance object from the Spring container based on the class type.

So the first step is to maintain the class type corresponding to each command.

So the relationship between the command and the class type is maintained in the previous enumeration, and you only need to know the command to know its class type.

In this way, it only takes two lines of code to replace the previously complex if else, and at the same time it can be extended flexibly.

Of course, you can also be more flexible, for example, there is no need to explicitly maintain the correspondence between commands and class types.

You only need to scan all classes that implement the InnerCommand interface when the application starts, and there is a similar implementation in cicada.

There is too much about the if else in the project, so much for refactoring. I hope the above content can improve everyone. If you want to learn more knowledge, please pay more attention to the editor's updates. Thank you for following the website!

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