Online-Academy
Look, Read, Understand, Apply

OOAD - Object Oriented Analysis and Design

Factory and Observer

Not GoF Factory

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
class form extends JFrame{
    JTextField tname;
    JTextField taddress;
    public form(){
        tname = new JTextField(20);tname.setBounds(20,20,100,25);
        taddress = new JTextField(20);taddress.setBounds(20,50,100,25);
        setLayout(null);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setVisible(true);
        add(tname);
        add(taddress);
        setSize(400,400);
    }
}
class bac_form extends form{
    JTextField jschool;
    public bac_form(){
        jschool = new JTextField("Enter School");jschool.setBounds(20,80,100,25);
        add(jschool);
    }
}
class mas_form extends form{
    JTextField jcollege;
    public mas_form(){
        jcollege = new JTextField("Enter College");jcollege.setBounds(20,80,100,25);
        add(jcollege);
    }
}
class form_factory{
    form f; 
    public form_factory(){
        //f = new form();
    }
    public form getForm(String type){
        switch(type){
            case "bachelor": f = new bac_form();
            break; 
            case "master": f = new mas_form();
            break;
        }
        return f; 
    }
}
class gui extends JFrame{
    JButton jbbac,jbmas;
    public gui(){
        setLayout(null);
        setSize(300,300);
        setVisible(true);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        jbbac = new JButton("Bachelor");jbbac.setBounds(20,20,100,25);
        jbmas = new JButton("Master");jbmas.setBounds(130,20,100,25);
        add(jbbac);
        add(jbmas);
        jbbac.addActionListener(new formFactory_demo("bachelor"));
        jbmas.addActionListener(new formFactory_demo("master"));
    }
}
class formFactory_demo implements ActionListener{
    String level; 
    form_factory ff;
    static form f;
    public formFactory_demo(String level){
        ff  = new form_factory();
        this.level = level;
    }
    public void actionPerformed(ActionEvent ae){
        f = ff.getForm(level);
    }
    public static void main(String[] aa){
        gui g = new gui();

    }
}

Observer

import java.util.*;
interface students{
    public void setName(String n);
    public String getName();
    public void getNotification();
}
class student implements students {
    String name;
    String message;
    teacher t;
    public student(){}
    public student(teacher t){
        this.t = t;
        this.t.register(this);
    }
    public void setName(String name){
        this.name = name;
    }
    public String getName(){return name;}
    public void getNotification(){
        this.message = t.getMessage();
        System.out.println(name+" Message: "+this.message);
    }
}
class teacher{
    String message;
    ArrayList list;
    public teacher(){list = new ArrayList();}
    public void updateMessage(String message){
        this.message = message;
        notifyall();
    }
    public String getMessage(){return message;}
    public void register(students s){list.add(s);}
    public void notifyall(){
        for (students s : list) {
            s.getNotification();
        }
    }
}
class observer{
    public static void main(String[] para){
        teacher t = new teacher();
        student s = new student(t);s.setName("Anil");
        student s1 = new student();s1.setName("Laxmi");
        student s2 = new student(t);s2.setName("Prabin");
        student s3 = new student(t);s3.setName("Soheel");
        t.updateMessage("Today is holiday!!!");
    }
}