{"id":2662,"date":"2023-07-16T09:19:44","date_gmt":"2023-07-16T07:19:44","guid":{"rendered":"https:\/\/radoslaw-gucwa.profesjonalnyprogramista.pl\/?p=2662"},"modified":"2023-07-18T10:35:09","modified_gmt":"2023-07-18T08:35:09","slug":"single-responsibility","status":"publish","type":"post","link":"https:\/\/radoslaw-gucwa.profesjonalnyprogramista.pl\/?p=2662","title":{"rendered":"Single Responsibility Principle"},"content":{"rendered":"

Under this statement hides principle which developers should be familiar with, since creating functions\/methods. This principle states, that each class should be responsible for one <\/strong>specified thing. Let’s have a look at code below:<\/p>\n\n

\nclass Person\n{\n    public string Name { get; set; }\n    public string LastName { get; set; }\n    public string City { get; set; }\n    public string Street { get; set; }\n    public int HouseNumber { get; set; }\n    public string Email { get; set; }\n    \n    public Person(string name, string lastname, string email)\n    {\n        Name = name;\n        LastName = lastname;\n        Email = ValidateEmail(email);\n    }\n    \n    public static bool ValidateEmail(string email)\n    {\n        string pattern = @"^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\\.[a-zA-Z]{2,}$";\n\n       \n        bool isValid = Regex.IsMatch(email, pattern);\n\n        return isValid;\n    }\n}\n<\/pre><\/div>\n\n
What exactly is going on above? We have declared a class, which has tons of incompetently declared properties and ValidateEmail<\/span> method which do not fit. Here comes the question \u2013 why is that? <\/p>\n
First of all \u2013 properties City<\/span>, Street<\/span> or HouseNumber<\/span> from the beginning don\u2019t sound like Person’s property \u2013 they sound more like an address. We can assume, that given person may live there, but it is not certain – from programming point of view – these properties are not related with class name.  Secondly \u2013 class Person<\/span> contains ValidateEmail<\/span> method which shouldn\u2019t be responsible for Person<\/span> type. <\/p>\n
So what should be done? Crucial thing to achieve single responsibility principle is to split whole class to smaller classes, where every single class has it’s responsiblity :<\/p>\n\n
\n\/\/creating Address class and re-creating properties\nclass Address\n{\n    public string City { get; set; }\n    public string Street { get; set; }\n    public int HouseNumber { get; set; }\n}\n\n\/\/creating Person class with Address's class properties\nclass Person\n{\n    public string Name { get; set; }\n    public string Lastname { get; set; }\n    public string Email { get; set; }\n    public Address PersonAddress { get; set; }\n    \n    public Person(string name, string lastname, string email)\n    {\n        Name = name;\n        Lastname = lastname;\n        Email = email;\n    }\n}\n\/\/separated ValidateEmail() method, converted to class with unchanged e-mail validation logic\nclass EmailValidator\n{\n    public static bool ValidateEmail(string email)\n    {\n        string pattern = @"^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\\.[a-zA-Z]{2,}$";\n\n       \n        bool isValid = Regex.IsMatch(email, pattern);\n\n        return isValid;\n    }\n}\n \/\/ running Main method\n public static void Main(string[] args)\n    {\n        Console.WriteLine("Enter e-mail address");\n        string email = Console.ReadLine();\n\n        if (ValidateEmail(email))\n        {\n            Console.WriteLine("E-mail address correct");\n        }\n        else\n        {\n            Console.WriteLine("E-mail address incorrect");\n        }\n    }\n<\/pre><\/div>\n\n
But why is that principle so important?<\/p>\n
Lets assume, that our code is much bigger than shown above, and there somehow is a bug in our code. What would happen if there are many functionalities in our class that are responsible for things that these class shouldn’t be responsible for? Exactly – lots of code to review, overthinking what comes from etc. While having less functionalities but<\/strong> consistent<\/strong> with what class is responsible for, there is much less code to review and much less mess to clean up.<\/p>","protected":false},"excerpt":{"rendered":"
First of five SOLID principles explaining how important is Single Responsibility.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"elementor_theme","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","footnotes":""},"categories":[13],"tags":[],"class_list":["post-2662","post","type-post","status-publish","format-standard","hentry","category-solid-articles"],"_links":{"self":[{"href":"https:\/\/radoslaw-gucwa.profesjonalnyprogramista.pl\/index.php?rest_route=\/wp\/v2\/posts\/2662","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/radoslaw-gucwa.profesjonalnyprogramista.pl\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/radoslaw-gucwa.profesjonalnyprogramista.pl\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/radoslaw-gucwa.profesjonalnyprogramista.pl\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/radoslaw-gucwa.profesjonalnyprogramista.pl\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2662"}],"version-history":[{"count":82,"href":"https:\/\/radoslaw-gucwa.profesjonalnyprogramista.pl\/index.php?rest_route=\/wp\/v2\/posts\/2662\/revisions"}],"predecessor-version":[{"id":2835,"href":"https:\/\/radoslaw-gucwa.profesjonalnyprogramista.pl\/index.php?rest_route=\/wp\/v2\/posts\/2662\/revisions\/2835"}],"wp:attachment":[{"href":"https:\/\/radoslaw-gucwa.profesjonalnyprogramista.pl\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2662"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/radoslaw-gucwa.profesjonalnyprogramista.pl\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2662"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/radoslaw-gucwa.profesjonalnyprogramista.pl\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2662"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}