PHP Talk 'Refactoring - Improving the Design of Existing Code' - Moving Features Between Objects_PHP Tutorial

Mind Map







Introduction

Continuing the above PHP chat "Refactoring-Improving the Design of Existing Code" to reorganize your functions, continue to talk about refactoring.


Professional terminology

delegate: delegate
encapsulate:encapsulate
introduce: introduce

Preface

"Decide where to place responsibility" - Use refactoring to change the original design.







Explanation:
1. Class takes on too much and is bloated - Extract Class separates some responsibilities.
2. Class is irresponsible - Inline Class integrates it into another Class.
3. Class uses another Class - Hide Delegate to hide the relationship.
4. Undertake (3) Delegate Class changes frequently - Remove Middle Man.

Move Method

If a method in one class communicates a lot with another class, then we create a new function with similar functions in another class, turn the old function into a simple Delegating Method, or remove the old function .








Class diagram:


Motive:
1. If a class is highly coupled with another class, I will Move Method. ——Class is simpler and cleaner to implement the tasks delivered by the system.
2. To move some value fields, check whether the number of times another class is used is greater than the number of times the resident object is used.
Move Field

Situation: The fields in your class are used more by another class. Then create a new field in another class and modify the old field.






Extract Class

Situation: One class does what two classes do, then create a new Class and move the related Fields and Methods from the old Class to the new Class.








Inline Class
Situation: One of your Class has not done much (has not taken on enough responsibilities), then change the Class All features are moved to another Class, and then the original Class is removed.
Motivation: Inline Class is the opposite of Extract Class. ——Reverse the Extract Class example, because PhoneNumber is only used to read code and number.

Hide Delegate

Status: The customer directly calls Server Object's Delegate Class's Method, then create the function Method required by the client on the Server side to hide the delegation relationship.

Anyone who has studied object technology knows that although php allows you to declare field as public, but you should also hide field (private). As experience grows, there is more to encapsulate.

Look at an example below:

$person->getDepartment()->getManager() obviously reveals that if you want to find Xiaocai’s leader, you must go through the department, so what we have to do is hide the department. ——Can reduce coupling.




Remove Middle Man

Situation: If a Class does too many Simple Delegate, then we will call Delegate Class.
Motivation: In the example in Hide Delegate when there are more new methods in Department, we want to Hide Delegate, you must add the corresponding method in Person to do Delegate use. At this time, Person has completely turned into a Middle Man. At this time, we should call Delegate directly Class——Department. The meaning of refactoring is: you never have to say sorry, as long as you fix the problem.









Introduce Foreign Method

Situation: There is an extra function in the PreviousEnd class that a class Client needs to use, but you cannot modify this class PreviousEnd, so you create a function in the Client and take a PreviousEnd entity as a parameter.









Summary

It should be noted that "Extract Class" and "Inline Class", "Hide Delegate" and "Remove Middle Man" are all opposite processes. For specific understanding, you can see the flow chart in the preface.

"Hide Delegate" is often used when using a small amount of "Delegate Method", and "Remove Middle Man" is used when calling many "Delegate Method". We can directly use Delegate Class to call, and some Delegate Method We reserve a portion as appropriate.

"Extract Class" and "Inline Class", "Extract Class" is often used in Classes that take on too many responsibilities and become bloated, while "Inline Class" is often used when the current class is "too irresponsible" use. ——I personally would rather "Extract Class" than "Inline Class".

Excerpted from Chuanshan Jia

http://www.bkjia.com/PHPjc/478312.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/478312.htmlTechArticleMind map introduction follows the above PHP chat "Refactoring - Improving the Design of Existing Code" to reorganize you Function, continue to talk about reconstruction. Professional term delegate: delegate enca...