Thread: Adding a value to a DefaultListModel via ListSelectionListener (JList)

import java.awt.*;
import javax.swing.*;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
 
public class HighScoreWindow {
 
    private JFrame frame;
 
    public HighScoreWindow() {
 
        frame = new JFrame();
    }
 
    public void showWindow(Component parent) {
 
        String[] value = {"A", "B", "C", "D", "E"};
 
        JPanel panel = new JPanel(new GridBagLayout());
        GridBagConstraints gc = new GridBagConstraints();
 
        final DefaultListModel playerListModel = new DefaultListModel();
        final DefaultListModel continentListModel = new DefaultListModel();
 
        for (int x = 0; x < value.length; x++) {
 
            playerListModel.addElement(value[x]);
        }
 
        final JList players = new JList(playerListModel);
        final JList continentScores = new JList(continentListModel);
        JScrollPane pListScroll = new JScrollPane(players);
        JScrollPane cScoreScroll = new JScrollPane(continentScores);
 
        continentScores.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
        continentScores.setBorder(BorderFactory.createLoweredBevelBorder());
        continentScores.setFont(new Font("Monospaced", Font.BOLD, 16));
 
        players.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
        players.setBorder(BorderFactory.createLoweredBevelBorder());
        players.setFont(new Font("Monospaced", Font.BOLD, 16));
        players.addListSelectionListener(new ListSelectionListener() {
 
            @Override
            public void valueChanged(ListSelectionEvent e) {
 
                continentListModel.addElement(players.getSelectedValue().toString());
            }
        });
 
        gc.gridx = 0;
        gc.gridy = 0;
        pListScroll.setPreferredSize(new Dimension(100, 400));
        panel.add(pListScroll, gc);
 
        gc.gridx = 1;
        gc.gridy = 0;
        gc.insets.left = 50;
        gc.anchor = GridBagConstraints.SOUTH;
        cScoreScroll.setPreferredSize(new Dimension(200, 200));
        panel.add(cScoreScroll, gc);
 
        frame.getContentPane().add(panel);
        frame.pack();
        frame.setResizable(false);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }
 
    public static void main(String[] args) {
 
        new HighScoreWindow().showWindow(null);
    }
}

how can i avoid duplicate values when im appending a value from a JList to another JList using its DefaultListModel? what method should i call to avoid duplicating an element added to a DefaultListModel?

but to be clear you only want events after adjustments have been made

ahh that would be enough, that makes sense now though, so instead, ill negate the value of it, a better approach