Event handling question

Question

I am very new to Swing....I am very confused about how event handling works. I created a button called "remove" and a list. When a user selects an item in the list and then clicks on the remove button, then the item should be deleted from the list. I am able to display the list and the button. I create a listener for the button in a separate class as follows:
class MyActionListener implements ActionListener
public void actionPerformed (ActionEvent e)
if(e.getActionCommand().equals("remove"))
{System.out.println("remove works");
Now my problem is ..how do i access the list in this class..because my list is set up in the other class (main class). Because if i try to do anything with the list in this class it shows the compile time error saying it cannot identify what list is. Please tell me how i can use the list in the MyActionListener class. Here is the code that sets up the list:
public abstract class VetNet extends JFrame implements ListSelectionListener
static DefaultListModel listM= new DefaultListModel();
static DefaultListModel listModel;
public static void main (String[] args)throws IOException
JPanel panel= new JPanel();
JLabel j=new JLabel("Welcome");
panel.add(j,BorderLayout.NORTH);
BufferedReader stdin=new BufferedReader(new InputStreamReader(System.in));
StringTokenizer reader;
reader=new StringTokenizer(stdin.readLine());
String first_name=reader.nextToken();
while(!first_name.equals("end"))
{ String last_name=reader.nextToken();
add_name(first_name,last_name);
reader=new StringTokenizer(stdin.readLine());
first_name=reader.nextToken();
}//while
DefaultListModel listModel=new DefaultListModel();
listModel=return_fname();
String first= (String)(listModel.firstElement());
JList sampleJList= new JList(listModel);
sampleJList.setVisibleRowCount(2);
// sampleJList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
//sampleJList.setSelectedIndex(0);
//sampleJList.addListSelectionListener(sampleJList);
JScrollPane listPane=new JScrollPane(sampleJList);
panel.setBorder(BorderFactory.createEmptyBorder(60,60,30,60));
panel.add(listPane);
JButton b1=new JButton("add");
panel.add(b1);
JButton b2=new JButton("remove");
panel.add(b2);
JButton b3=new JButton("edit");
panel.add(b3);
JFrame frame = new JFrame ("VetNet");
frame.getContentPane().add(panel);     
frame.addWindowListener(new WindowAdapter() {
     public void windowClosing (WindowEvent e) { System.exit(0); }
frame.pack ();
     frame.setVisible(true);
//MyActionListener myListener= new MyActionListener();
b1.addActionListener(new MyActionListener());
b2.addActionListener(new MyActionListener());
b3.addActionListener(new MyActionListener());
//sampleJList.addActionListener(new MyActionListener());
}//main
private static void add_name(String f_name, String l_name)
listM.addElement(l_name+ ", " + f_name);
}//method add_fname
private static DefaultListModel return_fname()
return listM;
}//method return_fname

Answer 1

Ok! This is the LONG answer, but I think you would benefit from reading it all.
Making something public means that it can be accessed from other classes; however, it must be accessed using an object(instance) of that class. This means, if I have a class MyJFrame that extends JFrame, then in another class, I can do this:
MyJFrame myFrame = new MyJFrame();
myFrame.dispose();
myFrame.isShowing = false;
Given that dispose() is a public method and isShowing is a public boolean variable that's in the MyJFrame object. Note: the opposite of public is private meaning that the variable/function is only accessible within the class. Also, in all my examples, I assume each class has access to the others.(in same Package, or imported)
There are times at which you do not want to call a function on a given object or you want variables that are defined in the CLASS context, not the OBJECT context. As in, I have the class MyJFrame, and I always want to be able to access every object(instance) of this class that I've created. I would accomplish this using a static variable. Define the variable the same place you would define any other variable of the class, but inclued the reserved word "static". As in:
public class MyJFrame{
public static Vector allFrames = new Vector();
then in my contructor, I would add this frame to the vector:
public MyFrame(){
allFrames.add(this);
Now that I have this set up, I can access all the frames I've made from anywhere using MyJFrame.allFrames (note that I use the CLASS name, and I don't have an instance of the object anywhere)
Another use of static is for functions. Going along with the same example, I could add a closeAllJFrames function:
public static void closeAllJFrames(){
for(int x=0; x<allFrames.size(); x++){
allFrames.elementAt(x).dispose();
then I can call this function from any other class using: MyJFrame.closeAllJFrames();
Also worth noting, this function could be placed in any other class(other than inner classes, which cannot have static functions), you'd just need to put MyJFrame. in front of the allFrames.
One last tip is: If you use code like I've shown, consider using a Hashtable instead of a Vector if you need to access certain frames(or whatevers) from afar. This will keep you from iterating thru the Vector and will decrease overhead significantly.
Hope this helps
--Zephryl