As you will one day discover, none of the most known principles in software development can be 100% followed. Programming is often about making compromises – abstract pureness vs. code size vs. speed vs.efficiency. You just need to learn to find the right balance: not let your application fall into abyss of chaos but not … Read more
It looks like Derek Greer is attempting to take a stab at this with his article series on SOLID JavaScript at Fresh Brewed Code: The Single Responsibility Principle The Open/Closed Principle The Liskov Substitution Principle The Interface Segregation Principle The Dependency Inversion Principle
Does IoC always break encapsulation, and therefore OOP? No, these are hierarchically related concerns. Encapsulation is one of the most misunderstood concepts in OOP, but I think the relationship is best described via Abstract Data Types (ADTs). Essentially, an ADT is a general description of data and associated behaviour. This description is abstract; it omits … Read more
Repository should have single responsibility – persist one kind of entity. E.g. employees. If you have to delete some associated records from other repository, it looks like business logic. E.g. When employee is fired we should remove his work log And usual place for business logic is a domain services. This service will have both … Read more
Let’s start with what does Single Responsibility Principle (SRP) actually mean: A class should have only one reason to change. This effectively means every object (class) should have a single responsibility, if a class has more than one responsibility these responsibilities become coupled and cannot be executed independently, i.e. changes in one can affect or … Read more
It means that you should put new code in new classes/modules. Existing code should be modified only for bug fixing. New classes can reuse existing code via inheritance. Open/closed principle is intended to mitigate risk when introducing new functionality. Since you don’t modify existing code you can be assured that it wouldn’t be broken. It … Read more
I’ve taken a class in college that spent two weeks around design patters, and read the Gang of Four book to no avail. Understanding what each pattern served for and how to use them to fit my problems was very hard for me, a developer that didn’t have much experience in OO programming. The book … Read more
Rich Domain Model (RDM) and Single Responsibility Principle (SRP) are not necessarily at odds. RDM is more at odds with a very specialised subclassof SRP – the model advocating “data beans + all business logic in controller classes” (DBABLICC). If you read Martin’s SRP chapter, you’ll see his modem example is entirely in the domain … Read more
SRP tells us that you should only have a single responsibility in a module. ISP tells us that you should not be forced to be confronted with more than you actually need. If you want to use a print() method from interface I, you shouldn’t have to instantiate a SwimmingPool or a DriveThru class for … Read more
This is easy once you realize that Object-Oriented Constructor Injection corresponds very closely to Functional Partial Function Application. First, I’d write Dings as a record type: type Dings = { Lol : string; Rofl : string } In F#, the IGetStuff interface can be reduced to a single function with the signature Guid -> seq<Dings> … Read more