How does the Proxy pattern work in Java

The Proxy pattern is a structural design pattern that allows you to provide a surrogate or placeholder for another object to control access to it. In Java, it is often used to control access to an object that is resource-intensive to create or where access should be restricted for security reasons.

How the Proxy Pattern Works

The Proxy pattern involves three main components:

Subject: This is the interface that both the RealSubject and Proxy implement.
RealSubject: This is the actual object that the Proxy represents. It performs the real operations.
Proxy: This class contains a reference to the RealSubject and controls access to it, adding additional functionality such as lazy initialization, access control, or logging.

Example of Proxy Pattern in Java


        // Subject interface
        interface Subject {
            void request();
        }

        // RealSubject class
        class RealSubject implements Subject {
            @Override
            public void request() {
                System.out.println("RealSubject: Handling request.");
            }
        }

        // Proxy class
        class Proxy implements Subject {
            private RealSubject realSubject;

            @Override
            public void request() {
                if (realSubject == null) {
                    realSubject = new RealSubject();
                }
                // Additional functionality can be added here if necessary
                realSubject.request();
            }
        }

        public class Client {
            public static void main(String[] args) {
                Subject proxy = new Proxy();
                proxy.request();  // First call, creates RealSubject
                proxy.request();  // Second call, uses cached RealSubject
            }
        }

How does the Proxy pattern work in Java

How the Proxy Pattern Works

Example of Proxy Pattern in Java

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How does the Proxy pattern work in Java

How the Proxy Pattern Works

Example of Proxy Pattern in Java

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