Grundlagen der OOP: Vererbung, Polymorphismus, Kapselung, Abstraktion

Polymorphismus ermöglicht es uns, die gleiche Methode für verschiedene Datentypen oder Klassen zu verwenden.Bei der Methodenüberladung können wir die gleiche Methode mit verschiedenen Parametertypen definieren.Bei der Methodenüberschreibung implementieren Unterklassen die gleiche Methode unterschiedlich.Zum Beispiel kann die Methode draw für verschiedene geometrische Formen unterschiedlich implementiert werden.Laufzeit-Polymorphismus erlaubt es uns, verschiedene Objekte über eine gemeinsame Schnittstelle zu behandeln.Encapsulation bundles data and methods together while controlling access from outside.Let's look at a BankAccount class with different levels of access control.Access modifiers define the visibility of class members. Private members are only accessible within the class.Protected members can be accessed by the class and its subclasses.Public members are accessible from anywhere in the program.When an external class tries to access the private balance directly, it's blocked.Instead, they must use the public getBalance method to access the balance safely.Encapsulation provides several benefits for data protection and code maintenance.Abstraction in object-oriented programming allows us to model complex systems by focusing on essential features while hiding implementation details.Let's look at a banking system example. We start with an abstract Account class that defines common attributes and behaviors.This abstract class contains essential account features like account number and balance, along with common operations like deposit and withdraw.Concrete classes like CheckingAccount and SavingsAccount implement these abstract concepts with specific behaviors.Interfaces provide another level of abstraction. The Transactional interface defines a contract for handling financial transactions.Here's how we implement abstraction in code. Notice how the abstract class provides both concrete and abstract methods.The abstract calculateInterest method must be implemented by each specific account type, while deposit is implemented in the base class.