Main.java Source code

Introduction

Here is the source code for Main.java

Source

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.HashMap;
import java.util.Map;

import javax.swing.JComboBox;
import javax.swing.JFrame;

public class Main {
    public Main() {
        Map<Integer, Student> map = createMap();
        JComboBox cbox = createComboBox(map);

        JFrame frame = new JFrame();
        frame.add(cbox);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    private Map<Integer, Student> createMap() {
        Map<Integer, Student> map = new HashMap<>();
        Student s1 = new Student(23, "M");
        Student s2 = new Student(6, "L");
        Student s3 = new Student(3, "C");
        Student s4 = new Student(8, "K");
        Student s5 = new Student(21, "T");

        map.put(s1.getId(), s1);
        map.put(s2.getId(), s2);
        map.put(s3.getId(), s3);
        map.put(s4.getId(), s4);
        map.put(s5.getId(), s5);

        return map;
    }

    private JComboBox createComboBox(final Map<Integer, Student> map) {
        final JComboBox cbox = new JComboBox();
        for (Integer id : map.keySet()) {
            cbox.addItem(id);
        }

        cbox.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                Integer id = (Integer) cbox.getSelectedItem();
                System.out.println(map.get(id));
            }
        });

        return cbox;
    }

    public static void main(String[] args) {

        new Main();

    }
}

class Student {

    String name;
    Integer id;

    public Student(int id, String name) {
        this.id = id;
        this.name = name;
    }

    public Integer getId() {
        return id;
    }

    @Override
    public String toString() {
        return "Name: " + name + " - Stud ID: " + id;
    }
}