import java.awt.*;
import java.awt.event.*;
import java.awt.font.*;
import java.awt.image.BufferedImage;
import javax.swing.*;

public class ExpandingPanels extends MouseAdapter {
    ActionPanel[] aps;
    JPanel[] panels;

    public ExpandingPanels() {
        assembleActionPanels();
        assemblePanels();
    }

    public void mousePressed(MouseEvent e) {
        ActionPanel ap = (ActionPanel) e.getSource();
        if (ap.target.contains(e.getPoint())) {
            ap.toggleSelection();
            togglePanelVisibility(ap);
        }
    }

    private void togglePanelVisibility(ActionPanel ap) {
        int index = getPanelIndex(ap);
        if (panels[index].isShowing())
            panels[index].setVisible(false);
        else
            panels[index].setVisible(true);
        ap.getParent().validate();
    }

    private int getPanelIndex(ActionPanel ap) {
        for (int j = 0; j < aps.length; j++)
            if (ap == aps[j])
                return j;
        return -1;
    }

    private void assembleActionPanels() {
        String[] ids = { "level 1", "level 2", "level 3", "level 4" };
        aps = new ActionPanel[ids.length];
        for (int j = 0; j < aps.length; j++)
            aps[j] = new ActionPanel(ids[j], this);
    }

    private void assemblePanels() {
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.insets = new Insets(2, 1, 2, 1);
        gbc.weightx = 1.0;
        gbc.weighty = 1.0;
        JPanel p1 = new JPanel(new GridBagLayout());
        gbc.gridwidth = gbc.RELATIVE;
        p1.add(new JButton