package org.opentrafficsim.road.network.lane.object.trafficlight;
   
   import org.djunits.unit.LengthUnit;
   import org.djunits.value.vdouble.scalar.Length;
   import org.opentrafficsim.core.network.NetworkException;
   import org.opentrafficsim.road.network.lane.Lane;
   import org.opentrafficsim.road.network.lane.object.AbstractLaneBasedObject;
   import org.opentrafficsim.road.network.lane.object.LaneBasedObject;
   
  import nl.tudelft.simulation.dsol.simulators.DEVSSimulatorInterface;
  import nl.tudelft.simulation.language.Throw;
  
  /**
   * Basic, abstract implementation of a traffic light.
   * <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/docs/license.html">OpenTrafficSim License</a>.
   * </p>
   * $LastChangedDate: 2015-07-24 02:58:59 +0200 (Fri, 24 Jul 2015) $, @version $Revision: 1147 $, by $Author: averbraeck $,
   * initial version Nov 30, 2015 <br>
   * @author <a href="http://www.tbm.tudelft.nl/averbraeck">Alexander Verbraeck</a>
   * @author <a href="http://www.tudelft.nl/pknoppers">Peter Knoppers</a>
   */
  public abstract class AbstractTrafficLight extends AbstractLaneBasedObject implements TrafficLight
  {
      /** */
      private static final long serialVersionUID = 201601001L;
  
      /** The color of the traffic light. */
      private TrafficLightColor trafficLightColor;
  
      /** The simulator to schedule events on. */
      private final DEVSSimulatorInterface.TimeDoubleUnit simulator;
  
      /** Default elevation of a traffic light (above zero; don't use this for lanes at non-zero elevation). */
      public static final Length DEFAULT_TRAFFICLIGHT_ELEVATION = new Length(1, LengthUnit.METER);
  
      /**
       * Construct an AbstractTrafficLight with specified elevation.
       * @param id traffic light id
       * @param lane lane where the traffic light is located
       * @param longitudinalPosition position of the traffic light on the lane, in the design direction
       * @param simulator the simulator for animation and timed events
       * @param height Length; the elevation of the traffic light
       * @throws NetworkException on failure to place the object
       */
      public AbstractTrafficLight(final String id, final Lane lane, final Length longitudinalPosition,
              final DEVSSimulatorInterface.TimeDoubleUnit simulator, final Length height) throws NetworkException
      {
          super(id, lane, longitudinalPosition, LaneBasedObject.makeGeometry(lane, longitudinalPosition), height);
  
          Throw.whenNull(simulator, "Simulator may not be null");
          this.simulator = simulator;
  
          this.trafficLightColor = TrafficLightColor.GREEN;
      }
  
      /**
       * Construct an AbstractTrafficLight at default elevation (use only on roads at elevation 0).
       * @param id traffic light id
       * @param lane lane where the traffic light is located
       * @param longitudinalPosition position of the traffic light on the lane, in the design direction
       * @param simulator the simulator for animation and timed events
       * @throws NetworkException on failure to place the object
       */
      public AbstractTrafficLight(final String id, final Lane lane, final Length longitudinalPosition,
              final DEVSSimulatorInterface.TimeDoubleUnit simulator) throws NetworkException
      {
          this(id, lane, longitudinalPosition, simulator, DEFAULT_TRAFFICLIGHT_ELEVATION);
      }
  
      /** {@inheritDoc} */
      @Override
      public final TrafficLightColor getTrafficLightColor()
      {
          return this.trafficLightColor;
      }
  
      /** {@inheritDoc} */
      @Override
      public final void setTrafficLightColor(final TrafficLightColor trafficLightColor)
      {
          this.trafficLightColor = trafficLightColor;
          fireTimedEvent(TRAFFICLIGHT_CHANGE_EVENT, new Object[] { getId(), this, trafficLightColor },
                  this.simulator.getSimulatorTime());
      }
  
  }