Proxy

Example 1:

package az.proxy;

import java.util.Date;

public class Attendance {

    private Date date;
    private boolean isPresent;

    public Attendance(Date date, boolean isPresent) {
        this.date = date;
        this.isPresent = isPresent;
    }

    public Date getDate() {
        return date;
    }

    public void setDate(Date date) {
        this.date = date;
    }

    public boolean isPresent() {
        return isPresent;
    }

    public void setPresent(boolean present) {
        isPresent = present;
    }
}

package az.proxy;

public interface DailySession {

    void attendLesson();

} 

package az.proxy;

public class Student implements DailySession {

    private Attendance attendance;

    public Student(Attendance attendance) {
        this.attendance = attendance;
    }

    public Attendance getAttendance() {
        return attendance;
    }

    public void setAttendance(Attendance attendance) {
        this.attendance = attendance;
    }

    @Override
    public void attendLesson() {
        System.out.println("Attending the session...");
    }

}

package az.proxy;

public class StudentProxy extends Student {

    public StudentProxy(Attendance attendance) {
        super(attendance);
    }

    @Override
    public void attendLesson() {
        if (getAttendance().isPresent()) {
            super.attendLesson();
        } else throw new RuntimeException("Student is not present");
    }

}

package az.proxy;

import java.util.Date;

public class Main {

    public static void main(String[] args) {
        Student student = new StudentProxy(new Attendance(new Date(), false));
        student.attendLesson();
    }

}

or

package az.proxy;

import java.util.Date;

public class Main {

    public static void main(String[] args) {
        DailySession student = new StudentProxy(new Attendance(new Date(), true));
        student.attendLesson();
    }

}

                                                                Dynamic Proxy

*** AOP using Dynamic Proxy