ActionListenerの実装

添付した画像のような画面を実装したい

各ボタンを押すと、選択したデータを格納、データをソート、データをリセットするようにしたい。

発生している問題

ActionPerformedメソッドの実装方法がわからない。

該当のソースコード

Java
import java.util.;
import java.awt.;
import java.awt.event.;
import javax.swing.;
import javax.swing.event.*;

class SortableDataStore implements Comparable<SortableDataStore>{
protected String productItem, noItem, orderInfo;
public SortableDataStore(String[] data) {

}
public SortableDataStore(String p, String n, String o) {
productItem = p;
noItem = n;
orderInfo = o;
}
public String toString() {

return new String(productItem + ", " + noItem + ", " + orderInfo) ;

}

// fill in the area to implement Comparable interface
}

public class ProductOrder extends JFrame implements ActionListener{
protected String list_Contents, noOrder, orderInfo;
protected SortableDataStore[] v = new SortableDataStore[20];

protected JPanel topp, leftp, rightp,bottomp,centerup, centerdown;
protected JButton putb, showb, sortb, clearb;
protected JLabel title, noorder, orderinfo;
protected JList plist;
protected JTextField nofield, infofield;
protected JTextArea contentsarea;
protected String[] data = {"IBM NoteBook", "Dell Product", "MS Windows", "Sun Workstation", "Oracle DB", "MySQL"};
protected int idx = 0;
protected int lastIndex = -1;

public ProductOrder() {
getContentPane().setLayout(new BorderLayout());
topp = new JPanel();
leftp = new JPanel();
rightp = new JPanel();
bottomp = new JPanel();
centerup = new JPanel();
centerdown = new JPanel();

getContentPane().add(topp, "North");
getContentPane().add(leftp, "West");
getContentPane().add(rightp, "Center");
getContentPane().add(bottomp, "South");

title = new JLabel("Product Order");
title.setFont(new Font("Product Order",Font.BOLD, 20));
topp.add(title);

plist = new JList(data);
plist.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
plist.addListSelectionListener(new ProductItemListener());
leftp.add(plist);

noorder = new JLabel("No. of Order Items");
orderinfo = new JLabel("Order Information");
nofield = new JTextField();
infofield = new JTextField();

putb = new JButton("Put into Cart");
putb.addActionListener(new PutButtonListener());
sortb = new JButton("Sort Items");
sortb.addActionListener(new SortButtonListener());
clearb = new JButton("Reset Cart");
clearb.addActionListener(new ResetButtonListener());

centerup.setLayout(new GridLayout(2,2));
centerup.add(noorder);
centerup.add(orderinfo);
centerup.add(nofield);
centerup.add(infofield);
centerdown.setLayout(new GridLayout(1,2));
centerdown.add(putb);
centerdown.add(sortb);
centerdown.add(clearb);

rightp.setLayout(new GridLayout(2,1));
rightp.add(centerup);
rightp.add(centerdown);

showb = new JButton("Show Cart");
showb.addActionListener(new ShowButtonListener());


contentsarea = new JTextArea(10,1);
bottomp.setLayout(new GridLayout(1,2));
bottomp.add(showb);
bottomp.add(contentsarea);

} // Product Order constructor

//event listeners.
//inner classes for the listeners.
public void actionPerformed(ActionEvent e) {
//Object o = e.getSource();
}

public static void main (String args[]) {
ProductOrder f = new ProductOrder();
f.setTitle("Product Order");
f.setSize(500,400);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setVisible(true);
}
} // end of ProductOrder