Understanding Enums
Enumerations, commonly called enums, are a practical yet often overlooked feature in object-oriented programming.
They let you define a fixed collection of named constants, which makes your code easier to read, less error-prone, and more structured.
When applied effectively, enums make programs more descriptive, act as built-in documentation, and prevent invalid values from sneaking into your logic.
What Exactly is an Enum?
An enum is a specialized data type that groups together a predefined list of constant values under a single label. Unlike raw integers or plain strings, enums enforce type safety — meaning you can’t assign an arbitrary value to a variable that expects a specific enum type.
Enums are most useful when a variable should only accept one choice out of a restricted set.
Everyday Examples of Enums
Payment Methods → CREDIT_CARD, PAYPAL, BANK_TRANSFER
Seasons → SPRING, SUMMER, AUTUMN, WINTER
Access Levels → GUEST, USER, MODERATOR, ADMIN
Traffic Light Signals → RED, YELLOW, GREEN
Using enums eliminates “magic values” (hardcoded strings or numbers), makes your intent clearer, gives compiler checks and IDE autocomplete support, and reduces the likelihood of accidental mistakes.
Example 1: A Simple Enum
Imagine a movie ticket booking system that tracks booking status:
Note : At any point you like to copy the code and run it for yourself click the image that has the code. It will take you to a github gist with the code.
Usage:
This way, only valid booking states are possible.
Example 2: Enum with Data and Behavior
Enums can hold extra details and even methods, giving them more flexibility.
Let’s define a Day Enum with working hours:
Usage:
Here, each enum constant carries extra information, making the code much richer and easier to maintain.
Pros and Cons of Enums
✅ Pros
Improves readability and structure.
Prevents invalid values.
Easy to extend with fields/methods.
IDE support (autocomplete, refactoring).
⚠️ Cons
Can be overused where simple constants suffice.
Not as flexible as external configuration (e.g., database values).
Adding/removing values may require code changes and redeployment.
Best Practices for Enums
Use enums when values are finite and well-defined (e.g., days of the week, roles, states).
Prefer enums over “magic numbers” or “hardcoded strings.”
Use fields/methods in enums if each constant carries additional data.
Avoid bloating enums with unrelated logic —keep them focused.
Thanks and See you in the next post.