package org.opentrafficsim.kpi.sampling.indicator;
   
   import java.util.HashSet;
   import java.util.List;
   import java.util.Set;
   
   import org.djunits.value.vdouble.scalar.Length;
   import org.djunits.value.vdouble.scalar.Time;
   import org.opentrafficsim.kpi.sampling.Query;
  import org.opentrafficsim.kpi.sampling.Trajectory;
  import org.opentrafficsim.kpi.sampling.TrajectoryGroup;
  
  /**
   * Sum of trajectory lengths divided by number of GTU's.
   * <p>
   * Copyright (c) 2013-2018 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved. <br>
   * BSD-style license. See <a href="http://opentrafficsim.org/node/13">OpenTrafficSim License</a>.
   * <p>
   * @version $Revision$, $LastChangedDate$, by $Author$, initial version 1 okt. 2016 <br>
   * @author <a href="http://www.tbm.tudelft.nl/averbraeck">Alexander Verbraeck</a>
   * @author <a href="http://www.tudelft.nl/pknoppers">Peter Knoppers</a>
   * @author <a href="http://www.transport.citg.tudelft.nl">Wouter Schakel</a>
   */
  public class MeanTripLength extends AbstractIndicator<Length>
  {
  
      /** {@inheritDoc} */
      @Override
      protected Length calculate(final Query query, final Time startTime, final Time endTime,
              final List<TrajectoryGroup> trajectoryGroups)
      {
          Length sum = Length.ZERO;
          Set<String> gtuIds = new HashSet<>();
          for (TrajectoryGroup trajectoryGroup : trajectoryGroups)
          {
              for (Trajectory<?> trajectory : trajectoryGroup.getTrajectories())
              {
                  sum = sum.plus(trajectory.getTotalLength());
                  gtuIds.add(trajectory.getGtuId());
              }
          }
          return sum.divideBy(gtuIds.size());
      }
  
      /** {@inheritDoc} */
      @Override
      @SuppressWarnings("checkstyle:designforextension")
      public String toString()
      {
          return "MeanTripLength []";
      }
  
  }