package org.opentrafficsim.core.gtu;
   
   import java.io.Serializable;
   
   import org.djunits.value.vdouble.scalar.Length;
   
   /**
    * A RelativePosition is a position on a GTU; e.g. the front, rear, position of the driver, etc. <br>
    * A RelativePosition stores the offset of the position from the reference position of the GTU.
   * <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: 2018-09-19 13:55:45 +0200 (Wed, 19 Sep 2018) $, @version $Revision: 4006 $, by $Author: averbraeck $,
   * initial version Dec 30, 2014 <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 class RelativePosition implements Serializable
  {
      /** */
      private static final long serialVersionUID = 20141231L;
  
      /** Positive x is in the normal direction of movement. */
      private final Length dx;
  
      /** Positive y is left compared to the normal direction of movement (seen from the top). */
      private final Length dy;
  
      /** Positive z is up. */
      private final Length dz;
  
      /** Type of relative position (FRONT, BACK, etc.). */
      private final TYPE type;
  
      /** Standard relative position type FRONT. */
      public static final TYPE FRONT = new TYPE("FRONT");
  
      /** Standard relative position type BACK. */
      public static final TYPE REAR = new TYPE("REAR");
  
      /** Standard relative position type CENTER. */
      public static final TYPE CENTER = new TYPE("CENTER");
  
      /** Standard relative position type REFERENCE. */
      public static final TYPE REFERENCE = new TYPE("REFERENCE");
  
      /** Standard relative position type DRIVER. */
      public static final TYPE DRIVER = new TYPE("DRIVER");
  
      /** Standard relative position type CONTOUR. There can be multiple points of type CONTOUR for one GTU. */
      public static final TYPE CONTOUR = new TYPE("CONTOUR");
  
      /** The reference position (always 0, 0, 0). */
      public static final RelativePosition REFERENCE_POSITION =
              new RelativePosition(Length.ZERO, Length.ZERO, Length.ZERO, RelativePosition.REFERENCE);
  
      /** the cached hash code. */
      private final int hash;
  
      /**
       * @param dx positive x is in the normal direction of movement.
       * @param dy positive y is left compared to the normal direction of movement (seen from the top).
       * @param dz positive z is up.
       * @param type type of relative position (FRONT, BACK, etc.).
       */
      public RelativePosition(final Length dx, final Length dy, final Length dz, final TYPE type)
      {
          super();
          this.dx = dx;
          this.dy = dy;
          this.dz = dz;
          this.type = type;
  
          this.hash = calcHashCode();
      }
  
      /**
       * @param p a relative position to make a deep copy of.
       */
      public RelativePosition(final RelativePosition p)
      {
          super();
          this.dx = p.getDx();
          this.dy = p.getDy();
          this.dz = p.getDz();
          this.type = p.getType();
  
          this.hash = calcHashCode();
      }
  
      /**
       * @return dx.
       */
      public final Length getDx()
      {
          return this.dx;
      }
  
     /**
      * @return dy.
      */
     public final Length getDy()
     {
         return this.dy;
     }
 
     /**
      * @return dz.
      */
     public final Length getDz()
     {
         return this.dz;
     }
 
     /**
      * @return type.
      */
     public final TYPE getType()
     {
         return this.type;
     }
 
     /** {@inheritDoc} */
     @Override
     public final String toString()
     {
         return "(" + this.dx + ", " + this.dy + ", " + this.dz + "): " + this.type;
     }
 
     /**
      * Calculate the hash code once.
      * @return the hash code.
      */
     public final int calcHashCode()
     {
         final int prime = 31;
         int result = 1;
         result = prime * result + ((this.dx == null) ? 0 : this.dx.hashCode());
         result = prime * result + ((this.dy == null) ? 0 : this.dy.hashCode());
         result = prime * result + ((this.dz == null) ? 0 : this.dz.hashCode());
         result = prime * result + ((this.type == null) ? 0 : this.type.hashCode());
         return result;
     }
 
     /** {@inheritDoc} */
     @Override
     @SuppressWarnings("checkstyle:designforextension")
     public int hashCode()
     {
         return this.hash;
     }
 
     /** {@inheritDoc} */
     @Override
     @SuppressWarnings({ "checkstyle:designforextension", "checkstyle:needbraces" })
     public boolean equals(final Object obj)
     {
         if (this == obj)
             return true;
         if (obj == null)
             return false;
         if (getClass() != obj.getClass())
             return false;
         RelativePosition other = (RelativePosition) obj;
         if (this.dx == null)
         {
             if (other.dx != null)
                 return false;
         }
         else if (!this.dx.equals(other.dx))
             return false;
         if (this.dy == null)
         {
             if (other.dy != null)
                 return false;
         }
         else if (!this.dy.equals(other.dy))
             return false;
         if (this.dz == null)
         {
             if (other.dz != null)
                 return false;
         }
         else if (!this.dz.equals(other.dz))
             return false;
         if (this.type == null)
         {
             if (other.type != null)
                 return false;
         }
         else if (!this.type.equals(other.type))
             return false;
         return true;
     }
 
     /**
      * The type of relative position, e.g., Front, Back, etc.
      * <p>
      * Copyright (c) 2013-2018 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. <br>
      * All rights reserved. <br>
      * BSD-style license. See <a href="http://opentrafficsim.org/docs/license.html">OpenTrafficSim License</a>.
      * <p>
      * $LastChangedDate: 2018-09-19 13:55:45 +0200 (Wed, 19 Sep 2018) $, @version $Revision: 4006 $, by $Author: averbraeck $,
      * initial version ec 31, 2014 <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 static class TYPE implements Serializable
     {
         /** */
         private static final long serialVersionUID = 20141231L;
 
         /** The type name. */
         private final String name;
 
         /** the cached hashcode. */
         private final int hash;
 
         /**
          * @param name the type name.
          */
         public TYPE(final String name)
         {
             super();
             this.name = name;
             this.hash = 31 + ((this.name == null) ? 0 : this.name.hashCode());
         }
 
         /**
          * @return name.
          */
         public final String getName()
         {
             return this.name;
         }
 
         /** {@inheritDoc} */
         @Override
         public final String toString()
         {
             return this.name;
         }
 
         /** {@inheritDoc} */
         @Override
         @SuppressWarnings("checkstyle:designforextension")
         public int hashCode()
         {
             return this.hash;
         }
 
         /** {@inheritDoc} */
         @Override
         @SuppressWarnings({ "checkstyle:designforextension", "checkstyle:needbraces" })
         public boolean equals(final Object obj)
         {
             if (this == obj)
                 return true;
             if (obj == null)
                 return false;
             if (getClass() != obj.getClass())
                 return false;
             TYPE other = (TYPE) obj;
             if (this.name == null)
             {
                 if (other.name != null)
                     return false;
             }
             else if (!this.name.equals(other.name))
                 return false;
             return true;
         }
 
     }
 
 }