Encapsulation
Domain: Design Principles
🎯 Motivation
Encapsulation hides internal state and requires all interaction through methods. This protects data from unexpected changes and makes behavior easier to evolve safely.
📋 Concrete Example
A BankAccount class stores balance privately and exposes deposit(amount) and withdraw(amount) methods. No outside code can set balance directly, preventing errors.
🔗 Analogy
A vending machine hides its wiring behind buttons. You press “cola” and get a drink; you never touch the gears, so you cannot break the mechanism.