package org.opentrafficsim.core.unit;
   
   import static org.opentrafficsim.core.unit.unitsystem.UnitSystem.CGS;
   import static org.opentrafficsim.core.unit.unitsystem.UnitSystem.IMPERIAL;
   import static org.opentrafficsim.core.unit.unitsystem.UnitSystem.MTS;
   import static org.opentrafficsim.core.unit.unitsystem.UnitSystem.OTHER;
   import static org.opentrafficsim.core.unit.unitsystem.UnitSystem.SI_DERIVED;
   
   import org.opentrafficsim.core.unit.unitsystem.UnitSystem;
  
  /**
   * The units of power.
   * <p>
   * Copyright (c) 2014 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 May 15, 2014 <br>
   * @author <a href="http://www.tbm.tudelft.nl/averbraeck">Alexander Verbraeck</a>
   */
  public class PowerUnit extends Unit<PowerUnit>
  {
      /** */
      private static final long serialVersionUID = 20140607L;
  
      /** the unit of mass for the power unit, e.g., kilogram. */
      private final MassUnit massUnit;
  
      /** the unit of length for the power unit, e.g., length. */
      private final LengthUnit lengthUnit;
  
      /** the unit of time for the power unit, e.g., second. */
      private final TimeUnit timeUnit;
  
      /** The SI unit for power is watt. */
      public static final PowerUnit SI;
  
      /** watt. */
      public static final PowerUnit WATT;
  
      /** kilowatt. */
      public static final PowerUnit KILOWATT;
  
      /** megawatt. */
      public static final PowerUnit MEGAWATT;
  
      /** gigawatt. */
      public static final PowerUnit GIGAWATT;
  
      /** foot-pound-force per hour. */
      public static final PowerUnit FOOT_POUND_FORCE_PER_HOUR;
  
      /** foot-pound-force per minute. */
      public static final PowerUnit FOOT_POUND_FORCE_PER_MINUTE;
  
      /** foot-pound-force per second. */
      public static final PowerUnit FOOT_POUND_FORCE_PER_SECOND;
  
      /** horsepower (metric). */
      public static final PowerUnit HORSEPOWER_METRIC;
  
      /** sthene-meter per second. */
      public static final PowerUnit STHENE_METER_PER_SECOND;
  
      /** erg per second. */
      public static final PowerUnit ERG_PER_SECOND;
  
      static
      {
          SI =
                  new PowerUnit(MassUnit.KILOGRAM, LengthUnit.METER, TimeUnit.SECOND, "PowerUnit.watt", "PowerUnit.W",
                          SI_DERIVED);
          WATT = SI;
          KILOWATT = new PowerUnit("PowerUnit.kilowatt", "PowerUnit.kW", SI_DERIVED, WATT, 1000.0);
          MEGAWATT = new PowerUnit("PowerUnit.megawatt", "PowerUnit.MW", SI_DERIVED, WATT, 1.0E6);
          GIGAWATT = new PowerUnit("PowerUnit.gigawatt", "PowerUnit.GW", SI_DERIVED, WATT, 1.0E9);
          FOOT_POUND_FORCE_PER_HOUR =
                  new PowerUnit(LengthUnit.FOOT, ForceUnit.POUND_FORCE, TimeUnit.HOUR,
                          "PowerUnit.foot_pound-force_per_hour", "PowerUnit.ft.lbf/h", IMPERIAL);
          FOOT_POUND_FORCE_PER_MINUTE =
                  new PowerUnit(LengthUnit.FOOT, ForceUnit.POUND_FORCE, TimeUnit.MINUTE,
                          "PowerUnit.foot_pound-force_per_minute", "PowerUnit.ft.lbf/min", IMPERIAL);
          FOOT_POUND_FORCE_PER_SECOND =
                  new PowerUnit(LengthUnit.FOOT, ForceUnit.POUND_FORCE, TimeUnit.SECOND,
                          "PowerUnit.foot_pound-force_per_second", "PowerUnit.ft.lbf/s", IMPERIAL);
          HORSEPOWER_METRIC = new PowerUnit("PowerUnit.horsepower_(metric)", "PowerUnit.hp", OTHER, WATT, 735.49875);
          STHENE_METER_PER_SECOND =
                  new PowerUnit(LengthUnit.METER, ForceUnit.STHENE, TimeUnit.SECOND, "PowerUnit.sthene-meter_per_second",
                          "PowerUnit.sn.m/s", MTS);
          ERG_PER_SECOND =
                  new PowerUnit(LengthUnit.CENTIMETER, ForceUnit.DYNE, TimeUnit.SECOND, "PowerUnit.erg_per_second",
                          "PowerUnit.erg/s", CGS);
      }
  
      /**
       * @param massUnit the unit of mass for the power unit, e.g., kilogram
       * @param lengthUnit the unit of length for the power unit, e.g., meter
       * @param timeUnit the unit of time for the power unit, e.g., second
       * @param nameKey the key to the locale file for the long name of the unit
       * @param abbreviationKey the key to the locale file for the abbreviation of the unit
      * @param unitSystem the unit system, e.g. SI or Imperial
      */
     public PowerUnit(final MassUnit massUnit, final LengthUnit lengthUnit, final TimeUnit timeUnit,
             final String nameKey, final String abbreviationKey, final UnitSystem unitSystem)
     {
         super(nameKey, abbreviationKey, unitSystem, WATT, massUnit.getConversionFactorToStandardUnit()
                 * lengthUnit.getConversionFactorToStandardUnit() * lengthUnit.getConversionFactorToStandardUnit()
                 / Math.pow(timeUnit.getConversionFactorToStandardUnit(), 3.0), true);
         this.massUnit = massUnit;
         this.lengthUnit = lengthUnit;
         this.timeUnit = timeUnit;
     }
 
     /**
      * @param lengthUnit the unit of length for the power unit, e.g., meter
      * @param forceUnit the unit of force for the power unit, e.g., Newton
      * @param timeUnit the unit of time for the power unit, e.g., second
      * @param nameKey the key to the locale file for the long name of the unit
      * @param abbreviationKey the key to the locale file for the abbreviation of the unit
      * @param unitSystem the unit system, e.g. SI or Imperial
      */
     public PowerUnit(final LengthUnit lengthUnit, final ForceUnit forceUnit, final TimeUnit timeUnit,
             final String nameKey, final String abbreviationKey, final UnitSystem unitSystem)
     {
         super(nameKey, abbreviationKey, unitSystem, WATT, lengthUnit.getConversionFactorToStandardUnit()
                 * forceUnit.getConversionFactorToStandardUnit() / timeUnit.getConversionFactorToStandardUnit(), true);
         this.massUnit = forceUnit.getMassUnit();
         this.lengthUnit = forceUnit.getLengthUnit();
         this.timeUnit = forceUnit.getTimeUnit();
     }
 
     /**
      * @param nameKey the key to the locale file for the long name of the unit
      * @param abbreviationKey the key to the locale file for the abbreviation of the unit
      * @param unitSystem the unit system, e.g. SI or Imperial
      * @param referenceUnit the unit to convert to
      * @param conversionFactorToReferenceUnit multiply a value in this unit by the factor to convert to the given
      *            reference unit
      */
     public PowerUnit(final String nameKey, final String abbreviationKey, final UnitSystem unitSystem,
             final PowerUnit referenceUnit, final double conversionFactorToReferenceUnit)
     {
         super(nameKey, abbreviationKey, unitSystem, referenceUnit, conversionFactorToReferenceUnit, true);
         this.massUnit = referenceUnit.getMassUnit();
         this.lengthUnit = referenceUnit.getLengthUnit();
         this.timeUnit = referenceUnit.getTimeUnit();
     }
 
     /**
      * @return massUnit
      */
     public final MassUnit getMassUnit()
     {
         return this.massUnit;
     }
 
     /**
      * @return lengthUnit
      */
     public final LengthUnit getLengthUnit()
     {
         return this.lengthUnit;
     }
 
     /**
      * @return timeUnit
      */
     public final TimeUnit getTimeUnit()
     {
         return this.timeUnit;
     }
 
     /** {@inheritDoc} */
     @Override
     public final PowerUnit getStandardUnit()
     {
         return WATT;
     }
 
     /** {@inheritDoc} */
     @Override
     public final String getSICoefficientsString()
     {
         return "kgm2/s3";
     }
 
 }