Proxy Pattern - Structural pattern

"It is used to provide the control for accessing the original object".

Proxy pattern is to provide a Surrogate or Placeholder for an object to control its references.

Subject: Interface implemented by the RealSubject and representing its services.

It is also implemented by Proxy.

Proxy: Controls access to the RealSubject and may be responsible for its creation and deletion.

RealSubject.

package designpattern.proxy;

public interface AdminRightAccess {

      public void grantInternetAccess();

}

public class AdminProxy implements AdminRightAccess {

      private String empId;

      private AdminAccess adminAccess;

      public AdminProxy(String empId) {

            this.empId = empId;

      }

      @Override

      public void grantInternetAccess() {

            if(getRole(empId)==1) {

                  adminAccess = new AdminAccess(empId);

                  adminAccess.grantInternetAccess();

            } else {

                  System.out.println("Admin rights given to "+ empId);

            }

      }

      public int getRole(String empId) {

            // Check role from the database based on empId

            // return 1; if employee is admin

            return 1;

      }

}

public class AdminAccess implements AdminRightAccess {

      private String empId;

      public AdminAccess(String empId) {

            this.empId = empId;

      }

      @Override

      public void grantInternetAccess() {

            System.out.println("Admin service loaded and"

                        + "rights given to "+ empId);

      }

}

package designpattern.proxy;

public class ProxyPatternClient {

      public static void main(String[] args) {

            AdminRightAccess access = new AdminProxy("Michael");

            access.grantInternetAccess();

      }

}

Output: Admin service loaded andrights given to Michael