Abstract method

An Abstract Method is an object-oriented programming language construct that is used to define an interface that classes must implement in order to qualify as implementations of the given interface. It defines a contractual agreement between the interface and its implementations, such that the implementers must provide implementations for each method specified in the interface, or else the instance cannot be used. It is typically used in conjunction with the proxy design pattern to provide a layer of abstraction between the user program and a remote server.

By using abstract methods, the Proxy object can be used to make changes before forwarding the request to the server. This allows for very granular restrictions to be implemented on requests and responses such as encryption, authentication or data manipulation. Because the method is called in the Proxy layer and not in the application code, there is less of a risk of code injection or malicious attempts to bypass the security.

There are a variety of applications of the abstract method pattern that can be used in conjunction with a proxy server. It can be used to enable centralized management of user authentication and authorization or to provide a high-level abstractions to more complex network functions. Abstract methods may also be used to provide higher-level APIs or to enable the incremental updates of applications over a network which can be advantageous in distributed systems.