J-WatchList/src/main/ui/guicomp/AddButt.java

package ui.guicomp;

import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JOptionPane;
import data.WatchList;

public class AddButt extends JButton {
    private WatchList wlist;

    public AddButt(WatchList wlist) {
        super("Add Stock...");
        //https://coderanch.com/t/580497/java/JButton-clicked-action
        if (getActionListeners().length < 1) {
            addActionListener(new AddButtList());
        }
        this.wlist = wlist;
    }

    private class AddButtList implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            //https://docs.oracle.com/javase/tutorial/uiswing/components/dialog.html#input
            //https://docs.oracle.com/javase/7/docs/api/javax/swing/JOptionPane.html
            System.out.println("Count of listeners: " + ((JButton) e.getSource()).getActionListeners().length);
            String userin = (String)JOptionPane.showInputDialog("Enter the identifier:");
            if ((userin != null) && (userin.length() > 0)) {
                new Thread(new Runnable() {
                    @Override
                    public void run() {
                        wlist.addStock(userin);
                        wlist.updateList();
                    }
                }).start();
            }
        }
    }
}