Abstract Class VS Interface in C#

You can open any C# tutorial and you’ll find some information about abstract classes and interfaces. Most likely, you’ll not find any information about what is the difference between abstract class and interface.
This theme was discussed earlier on the Internet several times but I want to consolidate all the most important thoughts regarding the problem of choosing between an abstract class and interface in this post.
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Objects Equality in C#. Important Facts That You Should Know

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C# provides many ways to compare objects, not only to compare class instances, but also structures. Actually, there are so many ways, that it requires to put them in order. All those possible options of comparing confuse people in case of misunderstanding them and their possible implementations.

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Cryptography in .NET for Beginners

This is a brief introduction into .NET cryptography.

Hashes

Hashing is a transformation process of some input data of an arbitrary length into an array of bytes of fixed size.
Hash is a one-side transformation function, the result of which cannot be reversed for receiving original input data. Very often it is used to store passwords. Even if an attacker gets a hash, he can’t retrieve the password from it. The length of a hash is determined by a hashing algorithm. In .NET you can find the following hashing algorithms (all of which derive from the HashAlgorithm base class):

  • MD5 — 128 bits in length
  • SHA (Secure Hash Algorithm) — there is no such a class, but there are SHA1 (160 bits), SHA256, SHA384, SHA512
  • KeydHashAlgorithm (also known as Message Authentication Code). Represented by the following classes of  algorithms: HMAC and MACTripleDES

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Hidden Dependencies as a Smell

Mark Seemann has written a nice post  “Service Locator violates encapsulation”. The name of the post speaks for itself that it’s about a pattern (anti-pattern) named Service Locator. When a programmer arbitrarily inside the code base calls for the IoC-container to resolve a dependency of an object – he uses a Service Locator anti-pattern. Mark provides the following example:

public class OrderProcessor : IOrderProcessor
{
    public void Process(Order order)
    {
        var validator = Locator.Resolve<IOrderValidator>();
        if (validator.Validate(order))
        {
            var shipper = Locator.Resolve<IOrderShipper>();
            shipper.Ship(order);
        }
    }
}

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Handling Exceptions and Errors. Part 1 – Intro.

In this article we will discuss exception handling best practices. There is a lack of meaningful information about exception handling on the Internet, so let’s go.
Have you ever seen that recommendation to avoid exception handling like this:

try { 
    //do something 
} 
catch(Exception ex) { 
}

Well, indeed, I agree that this exception handler looks pretty bad. But is it helpful to know only that? No, it is not. The problem of proper errors\exceptions handling is very far from being popular. There are some articles on the Internet, but I feel like there’s a lack of information on that topic, and this problem should be popularized among at least junior and middle developers.

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UpdateableSpin Synchronization Primitive

Today we are going to look at a relatively rare case of synchronization. There are no appropriate C# synchronization primitives out of the box.
In order to understand the case we’re going to talk about you can imagine the following case: “Your code makes a call to the third-party library’s method and you have to wait that method until the end. That method performs a sequence of operations and at each step it will invoke a callback. In addition, by the agreement that method takes a timeout which is a max amount of time allocated for each step. After a callback is invoked, timeout will be reset. If you passed in 60 seconds as a timeout, then that third-party’s method will take 60 seconds for each step (if there are three steps, then 3*60 sec. is a maximum time amount may be spent on the overall execution).”

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Refactoring: Extract a Method, When It’s Meaningful

Big Functions Hell

Well, now it’s hard to remember the moment, when I first time realized that it’s actually a good idea to extract functions from the massive chunks of useful code. Either I got this knowledge from the “Complete Code” or “Clean Code” – it’s hard to recall. Actually, it does not matter so much. We all know that we should split the business logic into well named functions. The longest function I’ve seen in my life was longer than 5k lines. I’m personally acquainted with that “programmer”. I remember when I first time faced that function. It’s not difficult to predict, that my very first reaction was – “WTF!!! Who made this piece of shit???” Yep, and that “programmer” is still hanging around in the office where I’m working on. I don’t want to get deeper into this story, but I want to mention that the 5k-lines-function was the core of the ~150k-lines program. That program was eventually driven to a corner because of that piece of shit, which tremendously influenced on the whole architecture of the application. In the end, the decision was made to rewrite that program completely from the ground.

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