Encapsulation concept

Encapsulation allows the internal state of an object be hidden from the outside world. External code cannot directly access or modify the attributes of an object; instead, interaction happens through public methods, which manage how data is accessed and changed. This principle protects the integrity of the object and enforces a controlled interaction.

Bank Account Example:

To demonstrate this principle, let’s revisit the BankAccount class. We will use encapsulation to restrict direct access to the account attributes and allow interactions only through the deposit() and withdraw() methods:

classDiagram
class BankAccount {
  - Int accountNumber
  - Int balance 
  - String accountHolder
  + deposit(amount)
  + withdraw(amount)
  + getBalance()
} 

Encapsulation ensures that an object’s internal state is protected from unintended interference, making it easier to maintain and modify code. It also improves the security and robustness of a program.

Why Encapsulation Matters?

Data Integrity

By restricting direct access to attributes, encapsulation helps ensure that the internal state of an object remains consistent. You can’t set invalid or unsafe values on the balance directly; instead, it’s modified through controlled methods that validate input.

Modularity

Encapsulation allows changes to the internal implementation of a class without affecting how other parts of the code interact with it. For example, you can change how getBalance() calculates the balance, and the external code won’t need to be updated.

Security

By keeping private attributes inaccessible from outside, encapsulation enhances security. For example, it prevents unauthorized or unintended modifications to critical data, like changing an account’s balance directly.

Ease of Maintenance

Encapsulation makes the codebase easier to maintain. Changes to internal workings of the object can be made without breaking the rest of the system since the external interface remains the same.