![]() ![]() That might not seem like a big deal, but it also affects all classes or components that depend on the changed class. That is obviously more often than you would need to change it if it had only one responsibility. You need to change your class as soon as one of its responsibilities changes. If your class implements multiple responsibilities, they are no longer independent of each other. The more responsibilities your class has, the more often you need to change it. ![]() Each of them also changes the responsibility of at least one class. We all know that requirements change over time. The argument for the single responsibility principle is relatively simple: it makes your software easier to implement and prevents unexpected side effects of future changes. Let’s address the most important questions before we dive any deeper into this design principle: Why should you use it and what happens if you ignore it? In this first post of my series about the SOLID principles, I will focus on the first one: the Single Responsibility Principle.Ī class should have one, and only one, reason to change. Benefits of the Single Responsibility Principle Following those principles doesn’t guarantee success, but avoiding them will lead in most cases to at least sub-optimal results in terms of functionality, cost, or both. The software is easier and cheaper to maintain, easier to understand, faster to develop in a team, and easier to test. In essence, the purpose of those principles is to allow developers to write better software. Martin they were known and used by lots of senior developers around the world. Although popularized and named by Robert C. Those are the insights that senior developers reached after decades of developing complex, enterprise-grade software. The solid principles are a set of best practices, transformed into a set of rules after dozens of years of cumulative development experience around the world done by software professionals. ![]() What Are the SOLID Principles And Why Are They Useful? It’s a mnemonic acronym for the following five design principles:Īll of them are broadly used and worth knowing. This is somewhat out of the norm for object oriented design, early object oriented design principles had as grouping together functions that operated on the same data structures so that the methods of a class would all manipulate the same variables of that class, but if those methods change for different reasons then they really belong in separate classes.SOLID is one of the most popular sets of design principles in object-oriented software development. So the Responsibility Principle simply says, "Find one reason to change and take everything else out of the class." So that you separate the things that change for different reasons, you group together the things to change for the same reasons. That means that this one class has three different reasons to change and there are probably many other classes that depend upon it and so as it changes those depending classes also suffer through change, they'll be effective or impacted by those changes. The save function will change if the DBA's decide that we needto change the database's schema. The report generator will change if the people who consume the reports want the format of the reports to change. The payroll, the calculate pay will change if the accountants decides on a new way of calculating pay. So for example, take a payroll application, if there's an employee class in that payroll application, you could imagine that it might have methods for calculate pay or perhaps another method for print a report, perhaps another method in the employee object for save me to the database, and what's unfortunate about these three methods existing in the same class is that they have all three completely different reasons to change. ![]() Single Responsibility Principle, what does it mean? It means that a software module should have one reason to change, then that's what I call a responsibility, a reason to change. (from SOLID Principles with Uncle Bob - Robert C. ![]()
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