package org.djunits.unit;
   
   import static org.djunits.unit.unitsystem.UnitSystem.IMPERIAL;
   import static org.djunits.unit.unitsystem.UnitSystem.SI_DERIVED;
   
   import org.djunits.unit.unitsystem.UnitSystem;
   
   /**
    * According to <a href="http://en.wikipedia.org/wiki/Velocity">Wikipedia</a>: Speed describes only how fast an object is
   * moving, whereas speed gives both how fast and in what direction the object is moving.
   * <p>
   * Copyright (c) 2015-2019 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved. <br>
   * BSD-style license. See <a href="http://djunits.org/docs/license.html">DJUNITS License</a>.
   * <p>
   * $LastChangedDate: 2019-03-02 19:06:46 +0100 (Sat, 02 Mar 2019) $, @version $Revision: 342 $, by $Author: averbraeck $,
   * initial version May 15, 2014 <br>
   * @author <a href="http://www.tbm.tudelft.nl/averbraeck">Alexander Verbraeck</a>
   */
  public class SpeedUnit extends LinearUnit<SpeedUnit>
  {
      /** */
      private static final long serialVersionUID = 20140607L;
  
      /** The unit of length for the speed unit, e.g., meter. */
      private final LengthUnit lengthUnit;
  
      /** The unit of time for the speed unit, e.g., second. */
      private final DurationUnit durationUnit;
  
      /** The SI unit for speed is m/s. */
      public static final SpeedUnit SI;
  
      /** m/s. */
      public static final SpeedUnit METER_PER_SECOND;
  
      /** m/h. */
      public static final SpeedUnit METER_PER_HOUR;
  
      /** km/s. */
      public static final SpeedUnit KM_PER_SECOND;
  
      /** km/h. */
      public static final SpeedUnit KM_PER_HOUR;
  
      /** in/s. */
      public static final SpeedUnit INCH_PER_SECOND;
  
      /** in/min. */
      public static final SpeedUnit INCH_PER_MINUTE;
  
      /** in/h. */
      public static final SpeedUnit INCH_PER_HOUR;
  
      /** ft/s. */
      public static final SpeedUnit FOOT_PER_SECOND;
  
      /** ft/min. */
      public static final SpeedUnit FOOT_PER_MINUTE;
  
      /** ft/h. */
      public static final SpeedUnit FOOT_PER_HOUR;
  
      /** mile/s. */
      public static final SpeedUnit MILE_PER_SECOND;
  
      /** mile/min. */
      public static final SpeedUnit MILE_PER_MINUTE;
  
      /** mile/h. */
      public static final SpeedUnit MILE_PER_HOUR;
  
      /** knot. */
      public static final SpeedUnit KNOT;
  
      static
      {
          SI = new SpeedUnit(LengthUnit.METER, DurationUnit.SECOND, "SpeedUnit.m/s", SI_DERIVED);
          METER_PER_SECOND = SI;
          METER_PER_HOUR = new SpeedUnit(LengthUnit.METER, DurationUnit.HOUR, "SpeedUnit.m/h", SI_DERIVED);
          KM_PER_SECOND = new SpeedUnit(LengthUnit.KILOMETER, DurationUnit.SECOND, "SpeedUnit.km/s", SI_DERIVED);
          KM_PER_HOUR = new SpeedUnit(LengthUnit.KILOMETER, DurationUnit.HOUR, "SpeedUnit.km/h", SI_DERIVED);
          INCH_PER_SECOND = new SpeedUnit(LengthUnit.INCH, DurationUnit.SECOND, "SpeedUnit.in/s", IMPERIAL);
          INCH_PER_MINUTE = new SpeedUnit(LengthUnit.INCH, DurationUnit.MINUTE, "SpeedUnit.in/min", IMPERIAL);
          INCH_PER_HOUR = new SpeedUnit(LengthUnit.INCH, DurationUnit.HOUR, "SpeedUnit.in/h", IMPERIAL);
          FOOT_PER_SECOND = new SpeedUnit(LengthUnit.FOOT, DurationUnit.SECOND, "SpeedUnit.fps", IMPERIAL);
          FOOT_PER_MINUTE = new SpeedUnit(LengthUnit.FOOT, DurationUnit.MINUTE, "SpeedUnit.ft/min", IMPERIAL);
          FOOT_PER_HOUR = new SpeedUnit(LengthUnit.FOOT, DurationUnit.HOUR, "SpeedUnit.ft/h", IMPERIAL);
          MILE_PER_SECOND = new SpeedUnit(LengthUnit.MILE, DurationUnit.SECOND, "SpeedUnit.mi/s", IMPERIAL);
          MILE_PER_MINUTE = new SpeedUnit(LengthUnit.MILE, DurationUnit.MINUTE, "SpeedUnit.mi/min", IMPERIAL);
          MILE_PER_HOUR = new SpeedUnit(LengthUnit.MILE, DurationUnit.HOUR, "SpeedUnit.mph", IMPERIAL);
          KNOT = new SpeedUnit(LengthUnit.NAUTICAL_MILE, DurationUnit.HOUR, "SpeedUnit.kt", IMPERIAL);
      }
  
      /**
       * Build a speed unit from a length unit and a time unit.
       * @param lengthUnit LengthUnit; the unit of length for the speed unit, e.g., meter
       * @param durationUnit DurationUnit; the unit of time for the speed unit, e.g., second
       * @param abbreviationKey String; the key to the locale file for the abbreviation of the unit
       * @param unitSystem UnitSystem; the unit system, e.g. SI or Imperial
      */
     private SpeedUnit(final LengthUnit lengthUnit, final DurationUnit durationUnit, final String abbreviationKey,
             final UnitSystem unitSystem)
     {
         super(abbreviationKey, unitSystem, METER_PER_SECOND, lengthUnit.getScaleFactor() / durationUnit.getScaleFactor());
         this.lengthUnit = lengthUnit;
         this.durationUnit = durationUnit;
     }
 
     /**
      * Build a user-defined speed unit from a length unit and a time unit.
      * @param lengthUnit LengthUnit; the unit of length for the speed unit, e.g., meter
      * @param durationUnit DurationUnit; the unit of time for the speed unit, e.g., second
      * @param name String; the long name of the unit
      * @param abbreviation String; the abbreviation of the unit
      * @param unitSystem UnitSystem; the unit system, e.g. SI or Imperial
      */
     public SpeedUnit(final LengthUnit lengthUnit, final DurationUnit durationUnit, final String name, final String abbreviation,
             final UnitSystem unitSystem)
     {
         super(name, abbreviation, unitSystem, METER_PER_SECOND, lengthUnit.getScaleFactor() / durationUnit.getScaleFactor());
         this.lengthUnit = lengthUnit;
         this.durationUnit = durationUnit;
     }
 
     /**
      * Build a SpeedUnit based on another SpeedUnit.
      * @param abbreviationKey String; the key to the locale file for the abbreviation of the unit
      * @param unitSystem UnitSystem; the unit system, e.g. SI or Imperial
      * @param referenceUnit SpeedUnit; the unit to convert to
      * @param scaleFactorToReferenceUnit double; multiply a value in this unit by the factor to convert to the given reference
      *            unit
      */
     private SpeedUnit(final String abbreviationKey, final UnitSystem unitSystem, final SpeedUnit referenceUnit,
             final double scaleFactorToReferenceUnit)
     {
         super(abbreviationKey, unitSystem, referenceUnit, scaleFactorToReferenceUnit);
         this.lengthUnit = referenceUnit.getLengthUnit();
         this.durationUnit = referenceUnit.getDurationUnit();
     }
 
     /**
      * Build a user-defined SpeedUnit with a conversion factor to another SpeedUnit.
      * @param name String; the long name of the unit
      * @param abbreviation String; the abbreviation of the unit
      * @param unitSystem UnitSystem; the unit system, e.g. SI or Imperial
      * @param referenceUnit SpeedUnit; the unit to convert to
      * @param scaleFactorToReferenceUnit double; multiply a value in this unit by the factor to convert to the given reference
      *            unit
      */
     public SpeedUnit(final String name, final String abbreviation, final UnitSystem unitSystem, final SpeedUnit referenceUnit,
             final double scaleFactorToReferenceUnit)
     {
         super(name, abbreviation, unitSystem, referenceUnit, scaleFactorToReferenceUnit);
         this.lengthUnit = referenceUnit.getLengthUnit();
         this.durationUnit = referenceUnit.getDurationUnit();
     }
 
     /**
      * @return lengthUnit
      */
     public final LengthUnit getLengthUnit()
     {
         return this.lengthUnit;
     }
 
     /**
      * @return durationUnit
      */
     public final DurationUnit getDurationUnit()
     {
         return this.durationUnit;
     }
 
     /** {@inheritDoc} */
     @Override
     public final SpeedUnit getStandardUnit()
     {
         return METER_PER_SECOND;
     }
 
     /** {@inheritDoc} */
     @Override
     public final String getSICoefficientsString()
     {
         return "m/s";
     }
 
 }