package org.opentrafficsim.core.unit;
   
   import static org.opentrafficsim.core.unit.unitsystem.UnitSystem.IMPERIAL;
   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 torque (moment of force).
   * <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 TorqueUnit extends Unit<TorqueUnit>
  {
      /** */
      private static final long serialVersionUID = 20140607L;
  
      /** The unit of mass for the torque unit, e.g., kilogram. */
      private final MassUnit massUnit;
  
      /** The unit of length for the torque unit, e.g., length. */
      private final LengthUnit lengthUnit;
  
      /** The unit of time for the torque unit, e.g., second. */
      private final TimeUnit timeUnit;
  
      /** The SI unit for torque is Newton meter. */
      public static final TorqueUnit SI;
  
      /** Newton meter. */
      public static final TorqueUnit NEWTON_METER;
  
      /** meter kilogram-force. */
      public static final TorqueUnit METER_KILOGRAM_FORCE;
  
      /** foot pound-force. */
      public static final TorqueUnit FOOT_POUND_FORCE;
  
      /** inch pound-force. */
      public static final TorqueUnit INCH_POUND_FORCE;
  
      static
      {
          SI =
                  new TorqueUnit(MassUnit.KILOGRAM, LengthUnit.METER, TimeUnit.SECOND, "TorqueUnit.Newton_meter",
                          "TorqueUnit.N.m", SI_DERIVED);
          NEWTON_METER = SI;
          METER_KILOGRAM_FORCE =
                  new TorqueUnit(ForceUnit.KILOGRAM_FORCE, LengthUnit.METER, "TorqueUnit.meter_kilogram-force",
                          "TorqueUnit.m.kgf", OTHER);
          FOOT_POUND_FORCE =
                  new TorqueUnit(ForceUnit.POUND_FORCE, LengthUnit.FOOT, "TorqueUnit.foot_pound-force",
                          "TorqueUnit.ft.lbf", IMPERIAL);
          INCH_POUND_FORCE =
                  new TorqueUnit(ForceUnit.POUND_FORCE, LengthUnit.INCH, "TorqueUnit.inch_pound-force",
                          "TorqueUnit.in.lbf", IMPERIAL);
      }
  
      /**
       * Create a torque unit from mass, length and time units.
       * @param massUnit the unit of mass for the torque unit, e.g., kilogram
       * @param lengthUnit the unit of length for the torque unit, e.g., meter
       * @param timeUnit the unit of time for the torque 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 TorqueUnit(final MassUnit massUnit, final LengthUnit lengthUnit, final TimeUnit timeUnit,
              final String nameKey, final String abbreviationKey, final UnitSystem unitSystem)
      {
          super(nameKey, abbreviationKey, unitSystem, NEWTON_METER, massUnit.getConversionFactorToStandardUnit()
                  * lengthUnit.getConversionFactorToStandardUnit() * lengthUnit.getConversionFactorToStandardUnit()
                  / (timeUnit.getConversionFactorToStandardUnit() * timeUnit.getConversionFactorToStandardUnit()), true);
          this.massUnit = massUnit;
          this.lengthUnit = lengthUnit;
          this.timeUnit = timeUnit;
      }
  
      /**
       * Create a torque unit from force and length units.
       * @param forceUnit the unit of force for the torque unit, e.g., Newton
       * @param lengthUnit the unit of length for the torque unit, e.g., m
       * @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 TorqueUnit(final ForceUnit forceUnit, final LengthUnit lengthUnit, final String nameKey,
              final String abbreviationKey, final UnitSystem unitSystem)
      {
          super(nameKey, abbreviationKey, unitSystem, NEWTON_METER, forceUnit.getConversionFactorToStandardUnit()
                  * lengthUnit.getConversionFactorToStandardUnit(), true);
          this.massUnit = forceUnit.getMassUnit();
          this.lengthUnit = forceUnit.getLengthUnit();
          this.timeUnit = forceUnit.getTimeUnit();
     }
 
     /**
      * Construct a torque unit based on another torque unit.
      * @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 TorqueUnit(final String nameKey, final String abbreviationKey, final UnitSystem unitSystem,
             final TorqueUnit 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 TorqueUnit getStandardUnit()
     {
         return NEWTON_METER;
     }
 
     /** {@inheritDoc} */
     @Override
     public final String getSICoefficientsString()
     {
         return "kgm2/s2";
     }
 
 }