AntiPattern The Big Ball Of Mud with Example in C#

mr. sci. Admir Mujkic
5 min readJul 18, 2023
https://senthilnayagan.com/design-patterns-and-coding-principles/2022/anti-pattern

Big Ball of Mud is a phrase that, when heard in software engineering circles, is bound to send shivers down any developer’s spine. This term doesn’t represent a badge of honor. Quite the contrary, it refers to a software antipattern, a kind of cautionary tale that tells us what we should strive to avoid in our coding endeavors. In this blog, we will untangle the Big Ball of Mud antipattern, unpack its pitfalls, and illustrate the concepts using examples in C#.

What is a “Big Ball of Mud”?

A Big Ball of Mud (BBOM) is a term that encapsulates the essence of a system that lacks any perceivable architecture. Picture a codebase where everything is intermingled, where there is no clear separation of concerns, no modularity, and every component depends heavily on every other.

A BBOM system grows “organically” with features tacked on haphazardly rather than being integrated thoughtfully. The result is a codebase that is, frankly, a nightmare to comprehend, maintain, or extend.

If we borrow the metaphor behind the name, a Big Ball of Mud system is essentially a massive, shapeless blob of code where everything is jumbled up with no apparent order or structure.

Unraveling The Big Ball Of Mud: An AntiPattern Example in C#

Big Ball of Mud is a phrase that, when heard in software engineering circles, is bound to send shivers down any developer’s spine. This term doesn’t represent a badge of honor.

Quite the contrary, it refers to a software antipattern, a kind of cautionary tale that tells us what we should strive to avoid in our coding endeavors. In this blog, we will untangle the “Big Ball of Mud” antipattern, unpack its pitfalls, and illustrate the concepts using examples in C#.

What Causes a “Big Ball of Mud”?

Several factors can contribute to a system devolving into a BBOM:

  1. Lack of design: Often, a BBOM originates because no initial architecture was planned, or the original plan was not followed diligently during development.
  2. Rapid development: When the drive to deliver features hastily takes precedence, it’s easy to take shortcuts that bypass good design principles.
  3. Lack of refactoring: As code piles up, it’s crucial to regularly refactor and tidy it. Without this, the code can morph into a tangled mess.
  4. Insufficient understanding of OO principles: Developers with a weak grasp of object-oriented (OO) principles, such as encapsulation, inheritance, and polymorphism, may misuse or neglect these essential tools, resulting in poorly structured code.

Why is it Bad?

The pitfalls of a BBOM become glaringly evident when you attempt to understand, maintain, or extend the system.

  1. Maintainability: Since everything is intricately intertwined, even minor changes or bug fixes can prove to be herculean tasks. In many cases, you might find that your solutions spawn more problems than they solve.
  2. Scalability: Adding new features to the system can become a Sisyphean task, as determining where and how to insert new code into the existing tangled mess is incredibly challenging.
  3. Onboarding: New developers often struggle to navigate the murky waters of a BBOM system. The result is a lengthy onboarding process, during which productivity takes a significant hit.
  4. Testing: Without clear divisions between components, it becomes significantly more challenging to write unit tests, a crucial element of software development.

C# Example of a Big Ball of Mud

Imagine you are developing an e-commerce system, and you have a Product class. This class is responsible for everything related to a product, including maintaining product data, calculating discounts, and even managing shipping information. The class looks like this:

class Product
{
public string Name { get; set; }
public decimal Price { get; set; }
public string Description { get; set; }
public string Category { get; set; }
public string ShippingAddress { get; set; }

public decimal CalculateDiscount()
{
if(Category == "Electronics")
{
return Price * 0.1M;
}
else
{
return Price * 0.05M;
}
}

public void ShipProduct(string newAddress)
{
ShippingAddress = newAddress;
}
}

This is a clear example of a BBOM in action. The Product class is doing too much, making it difficult to maintain, extend, or test.

Refactoring the Big Ball of Mud

Let’s refactor this code according to SOLID principles. We’ll create a Product class that is responsible only for maintaining product data.

class Product
{
public string Name { get; set; }
public decimal Price { get; set; }
public string Description { get; set; }
public string Category { get; set; }
}

Next, we’ll create a DiscountCalculator class for discount-related logic.

class DiscountCalculator
{
public decimal CalculateDiscount(Product product)
{
if(product.Category == "Electronics")
{
return product.Price * 0.1M;
}
else
{
return product.Price * 0.05M;
}
}
}

And finally, we’ll create a ShippingService class to handle shipping-related operations.

class ShippingService
{
public string ShippingAddress { get; set; }

public void ShipProduct(Product product, string newAddress)
{
ShippingAddress = newAddress;
}
}

Now our system’s responsibilities are distributed across several classes, each adhering to the Single Responsibility Principle. This makes our codebase more manageable, easier to extend, and simpler to test. It also prevents it from evolving into a Big Ball of Mud.

The Opposite of Big Ball of Mud

Now, you might be wondering, “What’s the opposite of the Big Ball of Mud? The answer lies in a set of design principles known as SOLID.

SOLID is an acronym that stands for five important design principles in object-oriented programming:

  1. Single Responsibility Principle (SRP): Each class should have a single responsibility or job.
  2. Open-Closed Principle (OCP): Software entities should be open for extension but closed for modification.
  3. Liskov Substitution Principle (LSP): Subtypes must be substitutable for their base types without causing issues.
  4. Interface Segregation Principle (ISP): It’s better to have many small, specialized interfaces rather than one large, general-purpose one.
  5. Dependency Inversion Principle (DIP): Depend on abstractions, not on concrete implementations.

These principles stand as the antithesis to the Big Ball of Mud antipattern. Applying them judiciously during the design and implementation of your system will guide you towards a clean, well-structured, and maintainable codebase.

It will be a codebase that is easy to understand, quick to extend with new features, convenient to onboard new team members, and straightforward to test — the exact opposite of a Big Ball of Mud system.

In conclusion, the Big Ball of Mud antipattern is a pitfall to avoid. Understanding its impacts and how to steer clear of it can lead to a cleaner, more manageable codebase, ultimately resulting in better software and a more productive development team. Embrace SOLID principles in your coding journey, and may your code never resemble a Big Ball of Mud.

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mr. sci. Admir Mujkic

Admir combined engineering expertise with business acumen to make a positive impact & share knowledge. Dedicated to educating the next generation of leaders.