How to re -structure code for single responsibility

Question

Hi

I am aware that we should have single class for single responsibility.

Refer code "dependency break" and it does A , B and C task which can easily done by three class mentioned in same code example. It was easy as there were no data members.

Refer another code "dependency break 2". Here also three tasks are there which I want to break into three classes. But I am confused like what and how to do.

First is to Fetch data from other server after authentication, then manipulate data and then write it in the excel file.

As it has three responsibility, I thought to split it into three classes.

But question and challenge is as below:

How to Initialize three class objects ? Should I initialize them into constructor of one another ?

Where to store (fetched data from data and structure mydata object in code) between first and second class ? In other words, Should I store data into class fetching it from database or should I store data into class who performs operations?

Feel free 2 ask in case of que

Answer 1

Adding both code as this first comment:
https://sololearn.com/compiler-playground/ci11XsoKVH5Z/?ref=app
https://sololearn.com/compiler-playground/c1xV3dZiLTzw/?ref=app

Answer 2

Got your point, but this is just a sample code.

In reality, it may become complex and we must have classes having their own responsibility rather than a single Class doing all the stuff.

Answer 3

The link seemed to have been copied badly. I found another link with even more design pattern examples. see the updated link.

here is the copy-pasted example from the site on how classes can be used as external dependencies.
https://sololearn.com/compiler-playground/cmF7g9di5GQp/?ref=app

Answer 4

why not keep them as methods? creating new classes just to use them as methods feels like overcomplication to me. Also, since you are going to be using shared data, using multiple classes could become unneccesarilly more complicated

Answer 5

maybe you can create methods that accepts the other classes as parameters if they are static classes or instances of or pointers to those classes if they are dynamic. It depends on what they ultimately do and how they are used.
Yes, you might even initialize them locally if you need their functionality.
As for where to store the data, again it depends on what data it is. It should be most accessible to the class that is primarilly using it.

It's the same situation when we use the standard library or external libraries. We sometimes instantiate them in classes, in functions or in in main(). The data can be encapsulated or it can be publicly shared and accessible. It depends on what we want to do.

Or maybe you are trying to model a dependency injection architecture?

https://www.bogotobogo.com/DesignPatterns/Dependency_Injection_Design_Pattern_Inversion_Of_Control_IoC.php

Answer 6

I am trying to understand what is good. Unfortunately, link you have shared is broken for me and cannot access.