Applying ISP in Larger Systems

In larger systems, ISP can be applied by splitting large service interfaces into smaller, more specific ones. For example, in a service-oriented architecture, you might have:

public interface IOrderService
{
    void PlaceOrder(Order order);
    void CancelOrder(int orderId);
    Order GetOrder(int orderId);
}

public interface IOrderProcessingService
{
    void ProcessOrder(int orderId);
}

public interface IOrderNotificationService
{
    void NotifyOrderPlaced(Order order);
    void NotifyOrderCancelled(int orderId);
}

Each service interface focuses on a specific aspect of order management, adhering to ISP.

Conclusion

The Interface Segregation Principle encourages designing interfaces that are specific to the needs of their clients. By creating smaller, more focused interfaces, you can build more maintainable, flexible, and understandable software systems. Adhering to ISP ensures that classes only implement methods they need, reducing the complexity and enhancing the cohesion of your codebase.