Hi. I am writing my first strategy, and I believe I have found a bug. I am using the strategy tester and only EUR/USD on hour ask bars. In my onBar() method I write some stuff to a file, then call getBar, and then write more stuff to a file. However, after the call to getBar, nothing more gets written to my file. I moved the getBar call to the beginning of onBar() and now nothing gets written to my file! If I comment out the getBar call then everything works as it should. Here are relevant snippets:

public class DataDownloader implements IStrategy {
    private IContext context = null;
    private IEngine engine = null;
    private IChart chart = null;
    private IIndicators indicators = null;
    private IHistory history = null;
    private IBar ibar = null;
}

public void onBar(Instrument instrument, Period period, IBar askBar, IBar bidBar) throws JFException {
      ibar = history.getBar(instrument, period, OfferSide.ASK, 1);

On a side note, it looks like I am receiving a lot of douplicate data. Here is an example:



Surely this should be fixed on the server side? I could pretty easily code something to check for duplicate data, but I would think that Dukascopy would want to fix something as simple as this on their end to provide better quality service... Or maybe this is just a demo thing? Does the data from a real live account contain duplicates like this? There seems to be one duplicate for every ten bars on average...

Note: I get the following error from jForex with the ibar=history.getbar(... line un-commented:

java.lang.NullPointerException @ DataDownloader.DataDownloader.onBar(DataDownloader.java:29)

My code doesn't work when I run the strategy live on the demo account either (rather than using the tester). I must be using something improperly... Does somebody see my mistake?

I found it, it was pretty obvious - I never assigned anything to the variable history, I just left it at null.

I have discovered another problem though. getBar with a shift of 1 returns the same open price as askBar (the current bar). Isn't getBar with a shift of 0 supposed to be the current bar?

Copy/pasting from my other thread, this is concerning the duplicate data I had written in my file.

0 is the bar that is not fully formed yet, "in-progress" bar. It changes as more ticks coming to fill it. 1 is the index of last formed bar, onBar called only on fully formed bars, so 1 is the same bar as askBar that you get in parameters