Hi,

I'm trying to get the equity in order to update a textField.
My first thought was to call a function that updates my textfield from
public void onAccount(IAccount acount) like this :

public void onAccount(IAccount account) throws JFException {

         equityUpdate = account.getEquity();
         myPanel.updateLabel(Double.toString(equityUpdate));

    }

But I get a nullPointerException on running the strategy :

java.lang.NullPointerException @ jforex.SwingTest.onAccount(SwingTest.java:45)


Then I tried to update a variable from onAccount(IAccount account) and
then update the value of my textField from onTick(Instrument instrument, ITick tick)
and it works !

public void onAccount(IAccount account) throws JFException {
        equityUpdate = account.getEquity();
    }

public void onTick(Instrument instrument, ITick tick) throws JFException {
         myPanel.updateLabel(Double.toString(equityUpdate));
    }

My question is why ??? I don't need to refresh the equity on each tick...

Thanks


Here is the whole code inspired from de swing test exemple.

package jforex;

import java.util.*;
import javax.swing.*;
import com.dukascopy.api.*;
import java.awt.BorderLayout;

import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.*;
import java.util.concurrent.Callable;

import javax.swing.*;

import com.dukascopy.api.*;
import com.dukascopy.api.IEngine.OrderCommand;
import com.dukascopy.api.IOrder.State;

public class SwingTest implements IStrategy {
    private IUserInterface userInterface;
    private JPanel myTab;
    private IConsole console;
    private MySpecialPanel myPanel;
    private double equityUpdate;
    private int counter = 0;
    
    
    public void onStart(IContext context) throws JFException {
        this.console = context.getConsole();
        this.userInterface = context.getUserInterface();
       
        myTab = userInterface.getBottomTab("Test");
        SwingUtilities.invokeLater(new Runnable(){
            @Override
            public void run() {
                myPanel = new MySpecialPanel();
                myTab.add(myPanel);
            }                       
        });
    }

    public void onAccount(IAccount account) throws JFException {

//
// I want to do this here but I have a null pointer exception
//
         equityUpdate = account.getEquity();
         myPanel.updateLabel(Double.toString(equityUpdate));
    }

    public void onMessage(IMessage message) throws JFException {
    }

    public void onStop() throws JFException {
       
    }

    public void onTick(Instrument instrument, ITick tick) throws JFException {
    
        
    }
   
    public void onBar(Instrument instrument, Period period, IBar askBar, IBar bidBar) throws JFException {
    }
   
   /* private String getLabel(int counter){
        StringBuffer newLabel = new StringBuffer();
        for (int i=1; i<=13; i++){
            if (counter != i)
                newLabel.append("1");
            else
                newLabel.append(i);
        }
        return newLabel.toString();
    }*/
   
    class MySpecialPanel extends JPanel{           
       // JLabel label;
        JTextField equityField;
       
        MySpecialPanel(){
        /*    this.label = new JLabel();
            this.add(label);*/
            
               this.equityField = new JTextField();
               equityField.setColumns(10);
               this.add(equityField);
            
        }
       
        public void updateLabel(final String value){
            SwingUtilities.invokeLater(new Runnable(){
                @Override
                public void run() {
                    if (equityField!=null)
                    //console.getOut().println("updateLabel() : "+MySpecialPanel.this.label);
                        MySpecialPanel.this.equityField.setText(value);   
                }                       
            });
        }
    }
}

the problem is that you are starting the thread that initializes myPanel by using SwingUtilities.invokeLater(...).
this method returns, before the code in run() has been executed and it seems that the first call to onAccount() happens before the execution of that thread is finished.
one possible solution is to use SwingUtilities.invokeAndWait(...) instead of invokeLater(...) but the big question is: why do you initialize your panel in a separate thread in the first place?
you could just write the following in onStart():

        this.console = context.getConsole();
        this.userInterface = context.getUserInterface();
       
        myTab = userInterface.getBottomTab("Test");
        myPanel = new MySpecialPanel();
        myTab.add(myPanel);

Hi Ocire, thanks for the response.

I understand.



Since I'm not good at java programing, I took the swing exemple from the support here :
https://www.dukascopy.com/swiss/english/forex/jforex/forum/viewtopic.php?f=31&t=4830

He starts the panel in a news thread, I guess it's better when you have some calculation in it.

best regards

ok, i see...
doing the update in a thread is ok if there is something that might take a long time... however the initialization should NOT be done in a thread as you expect it to be done when you leave onStart().
the reason why it works in the example is that the first tick will arrive quite a few ms, if not even a second or more after onStart() is called. and that gives the thread enough time to initialize everything.

ok thanks, I'll keep it in mind.

Best regards

You could just add a loop that waits until account is not null, and have it do a Thread.sleep(). It's a little dirty, but it works.

-Brian

Hi,

as an alternative to waiting until account is not null by using a thread.sleep()
you also could skip the processing of the ticks.

This has the advantage that you will not start processing on old/outdated tick and possibly missing newer ticks issued since, and you will always start your strategy processing with the newest tick after account initialization has taken place.

Best,
RR.

To avoid null pointer exception you need to initialize panel in invokeAndWait method. Please consider the following code:

    
        try {
        SwingUtilities.invokeAndWait(new Runnable(){
            @Override
            public void run() {
                myPanel = new MySpecialPanel();
                myTab.add(myPanel);
            }                       
        });
        } catch (Exception e) {
           console.getOut().println(e.getMessage());
        }