Stop Using If-Else Chains — Switch to Pattern Matching and Polymorphism
Coding best practices software developer should know
Hello guys, in my last a couple of articles I have shared coding and refactoring tip about why using Enum is better than boolean in method parameters and why refactor method with more than 3 parameters and feedback was awesome. You guys loved it.
Today, I am going to share a similar tip about simplifying your code and making it more extensible.
I f you have been programming for few years then you have noticed that in many codebases—especially those written by beginners or teams scaling fast—you’ll often find long chains of if-else or switch statements.
These branches may work for the moment, but they introduce a form of technical debt that’s hard to detect early on.
As an engineer who has reviewed hundreds of codebases and mentored developers in Java, Python, TypeScript, and more, I’ve seen how excessive conditional logic can silently degrade code readability, maintainability, and extensibility.
It’s time we move beyond if-else chains. Let’s explore a better approach using pattern matching and polymorphism.
A Problem with If-Else Chains
Let’s look at an example you might have written early in your career.
Example: Tax Calculator
This works. But what happens when:
You add 10 more countries?
Tax rules change and require more logic per country?
You want to unit test individual country tax rules?
Now you have a tightly coupled method with low cohesion and a high risk of regression with each change.
Refactor with Polymorphism
Let’s clean it up using object-oriented principles. Something along the Open Closed principle of SOLID principle which is not just used for code review but also heavily tested on Interviews.
Now a factory can resolve which implementation to use:
Usage:
Even Better: Pattern Matching (Java 21+)
Modern languages like Java, Python, and Scala now support pattern matching directly—making it more readable and powerful.
This syntax is cleaner and scales better. But for more complex behavior, polymorphism is still the more extensible choice.
By the way, if you don’t know, Java 21 introduces pattern matching for switch expressions, making your code:
More concise: No need for verbose
if-elseblocks.More readable: Clearly maps values to logic using modern syntax.
Safer: Exhaustiveness checking by the compiler ensures you don’t miss handling a case.
Expression-based:
switchcan now return values directly, like in functional programming.
As shown above, this example calculates tax rates based on a given countryCode, with a clean switch expression and a default fallback to handle unsupported countries.
Why This Matters in the Long Run?
Now, why you would do it? Well here are the few reasons which justifies doing this:
1. Maintainability: Adding a new condition in an if-else chain involves touching old code. With polymorphism, you add a new class without modifying others.
2. Testability: You can unit test individual behaviors (like GermanyTaxCalculator) in isolation.
3. Open/Closed Principle: Your code is open for extension (new calculators) but closed for modification.
4. Readability: Future developers will understand the code faster and with fewer bugs.
5. Flexibility: You can inject strategies (e.g., for A/B testing, different environments) without touching the logic structure.
Conclusion
If you're still writing lengthy if-else or switch statements, it's time to refactor. Embrace pattern matching where supported and adopt polymorphism for complex branching behavior.
Your future self—and your teammates—will thank you.
If you’re mentoring junior developers or doing code reviews, help them make this transition early. Cleaner code leads to better products, faster debugging, and more scalable systems.
✨ Bonus: Use CodeRabbit for Instant Code Reviews
While adopting modern Java features like pattern matching and polymorphism improves your code design, it’s equally important to get real-time feedback on your implementation.
That’s where CodeRabbit comes in. CodeRabbit is an AI-powered code review tool that integrates directly with your pull requests and gives you professional, context-aware code review comments — instantly.
Whether you're refactoring legacy if-else chains or introducing new switch expressions, CodeRabbit ensures your code is clean, idiomatic, and maintainable.
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No. Keep using the if-else chain or match.
This is not subtype polymorphism.
Subtype polymorphism requires differences of behavior. Your examples only have differences in data (the country's rate).
There is no difference in behavior in your examples.
A better example would be using a static table for Country -> Rate where calculations are simple and use the same function to calculate _income * rate_
Edit: I wanted to clarify. I better example to use for the non-polymorphic behavior would be to use map. A better example for the polymorphic behavior: 2 countries where the formulas are vastly different, or instances where one country's tax rate is determined by country alone, while another is determined by country, state and the person's previous residency in the last year.
OOP is a damn plague. Constantly misused, and a quintessential example of over-engineering. This is why Python is the most popular language.