High, I was looking for an indicator that would draw a line at the midpoint of the bar; basically (High+Low)/2, with a number next to it, giving the value.

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That's what it would look like, (sorry for the bad ASCII art). Thanks.

Try the following:

package charts.test;

import java.awt.Color;
import java.text.DecimalFormat;

import com.dukascopy.api.Configurable;
import com.dukascopy.api.IAccount;
import com.dukascopy.api.IBar;
import com.dukascopy.api.IChart;
import com.dukascopy.api.IChartObject.ATTR_INT;
import com.dukascopy.api.IContext;
import com.dukascopy.api.IMessage;
import com.dukascopy.api.IStrategy;
import com.dukascopy.api.ITick;
import com.dukascopy.api.Instrument;
import com.dukascopy.api.JFException;
import com.dukascopy.api.Period;
import com.dukascopy.api.drawings.ILabelChartObject;
import com.dukascopy.api.drawings.IShortLineChartObject;

public class ShortLineMidBar implements IStrategy {

   @Configurable("Period")
   public Period period = Period.TEN_SECS;
    @Configurable("Instrument")
    public Instrument instrument = Instrument.EURUSD;
    @Configurable("Line lenght (in bar widths)")
   public double barWidth = 1.5;
    
   private IChart chart;
   private DecimalFormat df = new DecimalFormat("0.00000");
   
   
   @Override
   public void onStart(IContext context) throws JFException {
      this.chart = context.getChart(Instrument.EURUSD);
   }
   @Override
   public void onTick(Instrument instrument, ITick tick) throws JFException {}
   @Override
   public void onBar(Instrument instrument, Period period, IBar askBar, IBar bidBar) throws JFException {
      if (instrument != this.instrument || period != this.period){
         return;
      }   
      double price = (bidBar.getHigh() + bidBar.getLow()) /2;
      long barMidTime = bidBar.getTime() + period.getInterval()/3;
      long lineLength = (long)(barWidth * period.getInterval());
      long lineStartTime = barMidTime - lineLength/2;
      long lineEndTime = barMidTime + lineLength/2;
      
      IShortLineChartObject line = chart.getChartObjectFactory().createShortLine();
      line.setTime(0, lineStartTime);
      line.setTime(1, lineEndTime);
      line.setPrice(0, price);
      line.setPrice(1, price);
      line.setText(df.format(price));
      line.setAttrInt(ATTR_INT.WIDTH, 3);
      line.setColor(Color.BLUE);
      chart.addToMainChart(line);   
      
      ILabelChartObject label = chart.getChartObjectFactory().createLabel();
      label.setTime(0, lineEndTime);
      label.setPrice(0, price);
      label.setText(df.format(price));
      label.setColor(Color.MAGENTA);
      chart.addToMainChart(label);
      
      
   }
   @Override
   public void onMessage(IMessage message) throws JFException {}
   @Override
   public void onAccount(IAccount account) throws JFException {}
   @Override
   public void onStop() throws JFException {}

}

Note that High+Low/2 means middle point between high and low, middle of the candle would be Close+Open/2.