context.getIndicatorChartPanel()
context.getFeedDescriptor()
both return null, at least on weekend.

package jforex;

import com.dukascopy.api.indicators.*;
import com.dukascopy.api.drawings.*;
import com.dukascopy.api.feed.*;
import com.dukascopy.api.*;
import java.awt.Color;
import java.io.*;

public class RiskControl implements IIndicator {
    private IndicatorInfo indicatorInfo;
    private InputParameterInfo[] inputParameterInfos;
    private OptInputParameterInfo[] optInputParameterInfos;
    private OutputParameterInfo[] outputParameterInfos;
    private double[][] inputs = new double[1][];
    private int timePeriod = 2;
    private double[][] outputs = new double[1][];
    private IIndicatorContext context;
    private IPriceMarkerChartObject slMarker;
    private IPriceMarkerChartObject tpMarker;
    private IPriceMarkerChartObject opMarker;
    private IFeedDescriptor feedDescriptor;
    
    public void onStart(IIndicatorContext context) {
        PrintStream stream = context.getConsole().getOut();
        context.getConsole().getOut().print("00");
     
        indicatorInfo = new IndicatorInfo("EXAMPIND", "Sums previous values", "My indicators",
            true, false, false, 1, 1, 1);
        
        inputParameterInfos = new InputParameterInfo[] {new InputParameterInfo("Input data", InputParameterInfo.Type.DOUBLE)};
        
        optInputParameterInfos = new OptInputParameterInfo[] {new OptInputParameterInfo("Time period", OptInputParameterInfo.Type.OTHER,
            new IntegerRangeDescription(2, 2, 100, 1))};
        
        outputParameterInfos = new OutputParameterInfo[] {new OutputParameterInfo("out", OutputParameterInfo.Type.DOUBLE,
            OutputParameterInfo.DrawingStyle.LINE)};
        
        IHistory history = context.getHistory();
        this.context = context;
        IIndicatorChartPanel panel = context.getIndicatorChartPanel();
        
        IChartObjectFactory factory = panel.getChartObjectFactory();
        //double balance = context.getAccount().getBalance();
     
        feedDescriptor = context.getFeedDescriptor();

/*      Period period = feedDescriptor.getPeriod();        
        Instrument instrument = feedDescriptor.getInstrument();
        
       try{

            double priceAsk = history.getBar(instrument, period, OfferSide.ASK, 0).getClose();
            double priceBid = history.getBar(instrument, period, OfferSide.BID, 0).getClose();
            double priceMid = (priceAsk + priceBid)/2.0;
            
            slMarker = factory.createPriceMarker("SL", priceMid - 20.0 * instrument.getPipValue());
            opMarker = factory.createPriceMarker("OP", priceMid);
            slMarker.setColor(Color.RED);
            opMarker.setColor(Color.ORANGE);
            slMarker.setLineWidth(2.0f);
            opMarker.setLineWidth(2.0f);
            
        } catch(Exception ex){
           context.getConsole().getErr().print(ex.toString());
        }
            stream.print(slMarker.getPrice(0));
            stream.print(opMarker.getPrice(0));
       */ 
    }

    public IndicatorResult calculate(int startIndex, int endIndex) {
        PrintStream stream = context.getConsole().getOut();
          context.getConsole().getNotif().println("00");
        
        //IConsole console = context.getConsole();
        //panel.add();
        
        //calculating startIndex taking into account lookback value
        if (startIndex - getLookback() < 0) {
            startIndex -= startIndex - getLookback();
        }
        int i, j;
        for (i = startIndex, j = 0; i <= endIndex; i++, j++) {
            double value = 0;
            for (int k = timePeriod; k > 0; k--) {
                value += inputs[0][i - k];
            }
            outputs[0][j] = value;
        }
        return new IndicatorResult(startIndex, j);
        
        //return new IndicatorResult(startIndex, 0);
    }

    public IndicatorInfo getIndicatorInfo() {
        return indicatorInfo;
    }

    public InputParameterInfo getInputParameterInfo(int index) {
        if (index <= inputParameterInfos.length) {
            return inputParameterInfos[index];
        }
        return null;
    }

    public int getLookback() {
        return timePeriod;
    }

    public int getLookforward() {
        return 0;
    }

    public OptInputParameterInfo getOptInputParameterInfo(int index) {
        if (index < optInputParameterInfos.length) {
            return optInputParameterInfos[index];
        }
        return null;
    }

    public OutputParameterInfo getOutputParameterInfo(int index) {
        if (index < outputParameterInfos.length) {
            return outputParameterInfos[index];
        }
        return null;
    }

    public void setInputParameter(int index, Object array) {
        inputs[index] = (double[]) array;
    }

    public void setOptInputParameter(int index, Object value) {
        timePeriod = (Integer) value;
    }

    public void setOutputParameter(int index, Object array) {
        outputs[index] = (double[]) array;
    }
}

These methods will return a value only when the indicator is attached to a chart.
They will return null when onStart is called during compilation or when indicator is called from a strategy.

Good to know.
That should be in remarks section in API documentation in the method documentation.