package org.opentrafficsim.kpi.sampling;
   
   import java.io.Serializable;
   import java.util.Iterator;
   import java.util.LinkedHashSet;
   import java.util.Set;
   
   import org.djutils.exceptions.Throw;
   import org.djutils.immutablecollections.ImmutableIterator;
  import org.opentrafficsim.kpi.interfaces.LaneDataInterface;
  import org.opentrafficsim.kpi.interfaces.LinkDataInterface;
  
  /**
   * A cross sections contains locations on lanes that together make up a cross section. It is not required that this is on a
   * single road, i.e. the cross section may any section in space.
   * <p>
   * Copyright (c) 2013-2020 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 Sep 29, 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 CrossSection implements Serializable
  {
  
      /** */
      private static final long serialVersionUID = 20160929L;
  
      /** Set of lane locations. */
      private final Set<KpiDirectedLanePosition> directedLanePositions;
  
      /**
       * Constructor with set of directed lane positions.
       * @param directedLanePositions Set&lt;KpiDirectedLanePosition&gt;; set of lane locations
       */
      public CrossSection(final Set<KpiDirectedLanePosition> directedLanePositions)
      {
          Throw.whenNull(directedLanePositions, "Directed lane positions may not be null.");
          this.directedLanePositions = new LinkedHashSet<>(directedLanePositions);
      }
  
      /**
       * Constructor with link and direction.
       * @param link LinkDataInterface; link
       * @param direction KpiGtuDirectionality; direction
       * @param fraction double; fraction on link
       * @throws SamplingException if an input is null
       */
      public CrossSection(final LinkDataInterface link, final KpiGtuDirectionality direction, final double fraction)
              throws SamplingException
      {
          Throw.whenNull(link, "Link lane positions may not be null.");
          Throw.whenNull(direction, "Direction may not be null.");
          this.directedLanePositions = new LinkedHashSet<>();
          for (LaneDataInterface lane : link.getLaneDatas())
          {
              KpiDirectedLanePosition directedLanePosition =
                      new KpiDirectedLanePosition(lane, lane.getLength().times(fraction), direction);
              this.directedLanePositions.add(directedLanePosition);
          }
      }
  
      /**
       * @return number of directed lane positions
       */
      public final int size()
      {
          return this.directedLanePositions.size();
      }
  
      /**
       * @return safe copy of directed lane positions
       */
      public final Set<KpiDirectedLanePosition> getDirectedLanePositions()
      {
          return new LinkedHashSet<>(this.directedLanePositions);
      }
  
      /**
       * @return iterator over directed lane positions
       */
      public final Iterator<KpiDirectedLanePosition> getIterator()
      {
          return new ImmutableIterator<>(this.directedLanePositions.iterator());
      }
  
      /** {@inheritDoc} */
      @Override
      @SuppressWarnings("checkstyle:designforextension")
      public String toString()
      {
          return "CrossSection [directedLanePositions=" + this.directedLanePositions + "]";
      }
  
  }