Hello, I'm attempting to utilize some of the code of the MQL to Jforex converter here at https://code.google.com/p/jftoolbox/source/browse/trunk/src/jforex/mql/MQLBridge.java

There are many valuable conversions here among them ihighest and ilowest that I would like to use. I have copied the functions into my strategy code. I have figured out how to get everything hooked up except one thing.

IBar[] bars = box.getNBars(symbol, convertedPeriod, offerSide, start, count);

From the original Ibox code https://code.google.com/p/jftoolbox/source/browse/trunk/src/jforex/api/IBox.java

I see it is an interface and I don't even understand exactly what this line does but I copied a snippet over from the Ibox java code and here is what I have in my strategy:

    public interface Ibox {
        IBar[] getNBars(Instrument instrument, Period period, OfferSide offerSide, int start, int count) throws JFException;             
    }

This is placed at the top of my

public class FullMarketDepth implements IStrategy {

So in the MQLbridge code they call the Ibox interface...

import jforex.api.IBox;

so I think I can use my code snippet instead of this but how do I get it working such that I can call box.getNBars?

So After I place the public interface Ibox I then call it using

protected IBox box = null;

So code looks like this

   public interface IBox {
        List<IBar> getLastBars(Instrument instrument, Period period, OfferSide offerSide, int bars, boolean takeUnformedBar) throws JFException;
        IBar[] getNBars(Instrument instrument, Period period, OfferSide offerSide, int start, int count) throws JFException;
    }
    protected IBox box = null;

I put in my strategy the ihighest code

protected int iHighest(Instrument symbol, int timeframe, int type, int count, int start) {
        return iHighest(symbol, timeframe, type, count, start, OfferSide.BID);
    }
    protected int iHighest  (Instrument symbol, int timeframe, int type, int count, int start, OfferSide offerSide) { 
        int rc = -1;
        if (symbol == null) {
            symbol = instrument;
        }
        Period convertedPeriod = convertPeriod(timeframe);

        try {
            IBar[] bars = box.getNBars(symbol, convertedPeriod, offerSide, start, count);         
            double highValue = Double.MIN_VALUE;
            for (int i = 0; i < bars.length; i++) {

                IBar bar = bars[i];

                double value = 0;
                switch (type) {
                case MODE_OPEN:
                    value = bar.getOpen();
                    break;
                case MODE_LOW:
                    value = bar.getLow();
                    break;
                case MODE_HIGH:
                    value = bar.getHigh();
                    break;
                case MODE_CLOSE:
                    value = bar.getClose();
                    break;
                case MODE_VOLUME:
                    value = bar.getVolume();
                    break;
                case MODE_TIME:
                    value = bar.getTime() / 1000;
                    break;
                default:
                    value = bar.getOpen();
                    break;
                }
                if (value > highValue) {
                    rc = i + start;
                    highValue = value;
                }
            }

        } catch (JFException e) {
            e.printStackTrace();
            context.stop();
        }
        return rc;
    }

In the Bar routine I then try to use the Ihighest code with

 for (int w=0;w<=lookbackbars;w++) {        
         int tempvollast3barsbar=iHighest(instrument,PERIOD_M1,MODE_VOLUME,2,w);}      

but when I run it, it gives me a runtime error of
05:32:22 java.lang.NullPointerException @ jforex.FullMarketDepth.iHighest(FullMarketDepth.java:659)

Please help. If I can get this working it will get a lot of code working...

Thank you!
TBB

Please give full example to reproduce the error.
Please note that we cannot give advice on programming that is not related to JForex API https://www.dukascopy.com/client/javadoc/.