How can I show thru jlabel a variable that is modfied by several threads?

Question

Dear all,
This is my problem, I have a variable, lets say m_money, m_money is been constantly modified by severeal threads, and it is also showed on my user interface using a jlabel componet, lets say m_jlabel_money. You have to take into account that if you want modify the state of a swing object with different threads you have to use something like invokeLater or another Swing utilities.
My question is how should I program my threads to modify m_money and m_jlabel_money at the same time without multithreading inconsistency?
I did this, but I am not sure if this is correct:
// function called by my threads
public synchronized void SetSaldoUsuarioMoneda(double money) {
          m_money=money;
          SwingUtilities.invokeLater(new ModifyJlabelState ());
//funtion which modify jlabel statte
     private class ModifyJlabelState implements Runnable {
              public void run() {
                    m_label_saldo.setText(m_money);
     }Is this correct?
Should I pass m_money to ModifyJlabelState thru its constructor or should I read m_money from ModifyJlabelState?
Is synchronized required or is it no sense?
Is this a better way or is going to fail bacause money variable may be different?
// function called by my threads
public synchronized void SetSaldoUsuarioMoneda(double money) {
          m_money=money;
          SwingUtilities.invokeLater(new ModifyJlabelState (money));
//funtion which modify jlabel statte
     private class ModifyJlabelState implements Runnable {
                  private double m_money;
                public ModifyJlabelState(double money) {m_money=money;}
              public void run() {
                    m_label_saldo.setText(m_money); // this m_money is/was what we had when we created this instance, so is this correct?
     }Well, I would like to know your opinions about this, because I don't know how should I solve this.
Thanks a lot.
Edited by: Ricardo_Ruiz_Lopez on Jun 24, 2008 1:01 AM
Edited by: Ricardo_Ruiz_Lopez on Jun 24, 2008 1:02 AM

Answer 1

Your first approach is incorrect. You either need to synchronize the 'setText' call or make m_money volatile.
Your second approach will work with the caveat that the value displayed on the label may be slightly out-of-date.