CPP Abstract Interface
“CPP abstract interface - a protocol.” (EMCppSfe 2021)
CPP abstract interface is a design pattern used in CPP programming to define a contract for derived classes without implementing any behavior. Introduced in year 1983, CPP abstract interfaces typically contain only pure virtual functions, making them different from abstract classes, which may contain both pure virtual and concrete methods. By using an abstract interface, developers define what actions should be available without dictating how those actions should be implemented, promoting flexibility and separation of concerns.
In the context of cloud-native applications, such as those utilizing Google Cloud or AWS, an abstract interface is often used to define common behaviors for diverse cloud services. For example, an interface could define methods like `connect()`, `disconnect()`, and `authenticate()`, which would be implemented differently by various cloud service classes (e.g., AWS S3 storage, Google Cloud virtual machines). This allows the application to interact with various services uniformly, without needing to rewrite logic for each specific implementation, improving code reuse and maintainability.
The key advantage of using an abstract interface in CPP is that it enforces consistency across different implementations. The interface guarantees that all derived classes implement a certain set of functions, ensuring that the application can rely on a consistent set of operations, regardless of the actual underlying implementation. This is particularly useful in large-scale systems or distributed systems, where components may be added or replaced over time. For instance, in a microservices architecture using Kubernetes, different services might implement the same interface to ensure they adhere to the same communication protocols and functional expectations.
One of the challenges in using abstract interfaces is that since no implementation is provided, all functionality must be implemented by the derived classes. This places the burden on the developer to ensure that the interface’s contract is fully realized in each implementation. However, the trade-off is worth it because abstract interfaces allow for a high degree of modularity and scalability. In the context of cloud infrastructure, abstract interfaces help maintain loose coupling between components, making it easier to update, replace, or extend the system with minimal disruption.