Nguyên tắc SOLID: Ví dụ Thực tế để Thiết Kế Phần Mềm Tốt Hơn

// Vi phạm SRP
class UserManager
{
public bool Authenticate(string username, string password) { /* Authentication logic */ }
public void UpdateProfile(User user) { /* Profile management logic */ }
}

// Tuân theo SRP
class AuthenticationManager
{
public bool Authenticate(string username, string password) { /* Authentication logic */ }
}
class ProfileManager
{
public void UpdateProfile(User user) { /* Profile management logic */ }
}

// Vi phạm SRP
class LogAndEmailService
{
public void Log(string message) { /* Logging logic */ }
public void SendEmail(string to, string subject, string body) { /* Email logic */ }
}

// Tuân theo SRP
class Logger
{
public void Log(string message) { /* Logging logic */ }
}
class EmailService
{
public void SendEmail(string to, string subject, string body) { /* Email logic */ }
}

// Vi phạm OCP
class ShapeCalculator
{
public double CalculateArea(Shape shape)
{
if (shape is Circle) { /* Calculate circle area */ }
else if (shape is Rectangle) { /* Calculate rectangle area */ }
// Adding a new shape requires modifying this class.
}
}

// Tuân theo OCP
abstract class Shape
{
public abstract double CalculateArea();
}
class Circle : Shape
{
public override double CalculateArea() { /* Calculate circle area */ }
}
class Rectangle : Shape
{
public override double CalculateArea() { /* Calculate rectangle area */ }
}
// Now, adding a new shape doesn't require modifying the ShapeCalculator class.

abstract class Bird
{
public virtual void Fly()
{
// Common fly behavior for all birds
}
}
class Ostrich : Bird
{
public override void Fly()
{
// Ostrich-specific behavior (e.g., running)
}
}
class Sparrow : Bird
{
// Sparrows can fly, so no method override needed
}
class Program
{
static void Main()
{
Bird ostrich = new Ostrich();
Bird sparrow = new Sparrow();
ostrich.Fly(); // Executes ostrich-specific behavior
sparrow.Fly(); // Executes common fly behavior
}
}

// Vi phạm ISP
interface IWorker
{
void Work();
void Eat();
}
class Robot : IWorker
{
public void Work() { /* Work logic */ }
public void Eat() { /* Eat logic, but not used by Robot */ }
}
Tuân thủ ISP
// Following ISP
interface IWorkable
{
void Work();
}
interface IEatable
{
void Eat();
}
class Robot : IWorkable
{
public void Work() { /* Work logic */ }
}

class MessageSender
{
private EmailService emailService;
private SmsService smsService;
public MessageSender()
{
emailService = new EmailService();
smsService = new SmsService();
}
public void SendEmail(string message)
{
emailService.Send(message);
}
public void SendSMS(string message)
{
smsService.Send(message);
}
}

interface IMessageService
{
void Send(string message);
}
class EmailService : IMessageService
{
public void Send(string message)
{
// Implementation to send an email
}
}
class SmsService : IMessageService
{
public void Send(string message)
{
// Implementation to send an SMS
}
}
class MessageSender
{
private IMessageService messageService;
public MessageSender(IMessageService service)
{
messageService = service;
}
public void SendMessage(string message)
{
messageService.Send(message);
}
}