Package edu.wpi.first.units

Class PerUnit<N extends Unit,D extends Unit>

java.lang.Object
edu.wpi.first.units.Unit
edu.wpi.first.units.PerUnit<N,D>
Type Parameters:
N - the type of the numerator unit
D - the type of the denominator unit
Direct Known Subclasses:
AccelerationUnit, AngularAccelerationUnit, AngularVelocityUnit, FrequencyUnit, LinearAccelerationUnit, LinearVelocityUnit, MomentOfInertiaUnit, PowerUnit, ResistanceUnit, VelocityUnit
public class PerUnit<N extends Unit,D extends Unit> extends Unit
Generic combinatory unit type that represents the proportion of one unit to another, such as Meters per Second or Radians per Celsius.

  • Constructor Summary

    Constructors
    Modifier
    Constructor
    Description
    protected
    PerUnit(PerUnit<N,D> baseUnit, N numerator, D denominator)
    Creates a new proportional unit derived from the ratio of one unit to another.

  • Method Summary

    Modifier and Type
    Method
    Description
    static <N extends Unit, D extends Unit>
    PerUnit<N,D>
    combine(N numerator, D denominator)
    Creates a new PerUnit unit derived from an arbitrary numerator and time denominator units.
    double
    convertFrom(double magnitude, PerUnit<? extends N,? extends D> otherUnit)
    Converts a measurement value in terms of another unit to this unit.
    D
    denominator()
    Gets the denominator unit.
    boolean
    equals(Object o)
     
    PerUnit<N,D>
    getBaseUnit()
    Gets the base unit of measurement that this unit is derived from.
    int
    hashCode()
     
    N
    mult(D denom)
    Multiplies this unit by a unit of its denominator.
    MutableMeasure<? extends PerUnit<N,D>,?,?>
    mutable(double initialMagnitude)
    Creates a new mutable measurement that is initialized to the given magnitude in terms of this unit.
    final MutPer<N,D>
    mutableNative(double initialMagnitude)
    Creates a new mutable measurement of the given magnitude in terms of the ratio unit.
    N
    numerator()
    Gets the numerator unit.
    Measure<? extends PerUnit<N,D>>
    of(double magnitude)
    Creates a new immutable measurement of the given magnitude in terms of this unit.
    Measure<? extends PerUnit<N,D>>
    ofBaseUnits(double baseUnitMagnitude)
    Creates a new immutable measurement of the given magnitude in terms of this unit's base unit.
    final Per<N,D>
    ofNative(double magnitude)
    Creates a new immutable measurement of the given magnitude in terms of the ratio unit.
    final Per<N,D>
    ofNativeBaseUnits(double baseUnitMagnitude)
    Creates a new immutable measurement of the given magnitude in terms of the ratio unit's base unit.
    Measure<? extends PerUnit<N,D>>
    one()
    Gets a measure with a magnitude of 1.0 in terms of this unit.
    Unit
    per(TimeUnit time)
    Combines this unit with a unit of time.
    PerUnit<D,N>
    reciprocal()
    Returns the reciprocal of this PerUnit.
    Measure<? extends PerUnit<N,D>>
    zero()
    Gets a measure of zero magnitude in terms of this unit.

    Methods inherited from class edu.wpi.first.units.Unit

    equivalent, fromBaseUnits, getConverterFromBase, getConverterToBase, isBaseUnit, name, symbol, toBaseUnits, toString

    Methods inherited from class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, wait, wait, wait

  • Constructor Details

    • PerUnit

      protected PerUnit(PerUnit<N,D> baseUnit, N numerator, D denominator)
      Creates a new proportional unit derived from the ratio of one unit to another. Subclasses of PerUnit should use this constructor.
      Parameters:
      baseUnit - the base unit. Set this to null if the unit being constructed is its own base unit
      numerator - the numerator unit
      denominator - the denominator unit

  • Method Details

    • combine

      public static <N extends Unit, D extends Unit> PerUnit<N,D> combine(N numerator, D denominator)
      Creates a new PerUnit unit derived from an arbitrary numerator and time denominator units. 
         PerUnit.combine(Volts, Meters) // possible PID constant
      Type Parameters:
      N - the type of the numerator unit
      D - the type of the denominator unit
      Parameters:
      numerator - the numerator unit
      denominator - the denominator for unit time
      Returns:
      the combined unit

    • getBaseUnit

      public PerUnit<N,D> getBaseUnit()
      Description copied from class: Unit
      Gets the base unit of measurement that this unit is derived from. If the unit is the base unit, the unit will be returned.

      NOTE: Subclasses must override this method to provide the correct return type. Failing to do say will make unit combinations that use it break at runtime! 

      
   Unit baseUnit = new Unit(null, ...);
   baseUnit.getBaseUnit(); // returns baseUnit

   Unit derivedUnit = new Unit(baseUnit, ...);
   derivedUnit.getBaseUnit(); // returns baseUnit
      Overrides:
      getBaseUnit in class Unit
      Returns:
      the base unit

    • numerator

      public N numerator()
      Gets the numerator unit. For a PerUnit<A, B>, this will return the A unit.
      Returns:
      the numerator unit

    • denominator

      public D denominator()
      Gets the denominator unit. For a PerUnit<A, B>, this will return the B unit.
      Returns:
      the denominator unit

    • reciprocal

      public PerUnit<D,N> reciprocal()
      Returns the reciprocal of this PerUnit.
      Returns:
      the reciprocal

    • mult

      public N mult(D denom)
      Multiplies this unit by a unit of its denominator.
      Parameters:
      denom - the denominator-typed unit to multiply by
      Returns:
      the result

    • of

      public Measure<? extends PerUnit<N,D>> of(double magnitude)
      Creates a new immutable measurement of the given magnitude in terms of this unit. Implementations are strongly recommended to sharpen the return type to a unit-specific measurement implementation.

      Note: When called on an object of type PerUnit (and not a subclass!), this method will always return a Per instance. If you want to avoid casting, use ofNative(double) that returns a Per instance directly.

      Specified by:
      of in class Unit
      Parameters:
      magnitude - the magnitude of the measure
      Returns:
      the ratio measure

    • ofBaseUnits

      public Measure<? extends PerUnit<N,D>> ofBaseUnits(double baseUnitMagnitude)
      Creates a new immutable measurement of the given magnitude in terms of this unit's base unit. Implementations are strongly recommended to sharpen the return type to a unit-specific measurement implementation.

      Note: When called on an object of type PerUnit (and not a subclass!), this method will always return a Per instance. If you want to avoid casting, use ofNativeBaseUnits(double) that returns a Per instance directly.

      Specified by:
      ofBaseUnits in class Unit
      Parameters:
      baseUnitMagnitude - the magnitude of the measure in terms of its base units.
      Returns:
      the ratio measure

    • ofNative

      public final Per<N,D> ofNative(double magnitude)
      Creates a new immutable measurement of the given magnitude in terms of the ratio unit. This will always return a Per object and cannot be overridden by subclasses.
      Parameters:
      magnitude - the magnitude of the measurement.
      Returns:
      the measurement object
      See Also:

    • ofNativeBaseUnits

      public final Per<N,D> ofNativeBaseUnits(double baseUnitMagnitude)
      Creates a new immutable measurement of the given magnitude in terms of the ratio unit's base unit. This will always return a Per object and cannot be overridden by subclasses.
      Parameters:
      baseUnitMagnitude - the magnitude of the measure in terms of its base units.
      Returns:
      the measurement object
      See Also:

    • zero

      public Measure<? extends PerUnit<N,D>> zero()
      Description copied from class: Unit
      Gets a measure of zero magnitude in terms of this unit. The returned object is guaranteed to be of the same type returned by Unit.of(double). Subclasses are encouraged to override this method to sharpen the return type.
      Overrides:
      zero in class Unit
      Returns:
      a zero-magnitude measure of this unit

    • one

      public Measure<? extends PerUnit<N,D>> one()
      Description copied from class: Unit
      Gets a measure with a magnitude of 1.0 in terms of this unit. The returned object is guaranteed to be of the same type returned by Unit.of(double). Subclasses are encouraged to override this method to sharpen the return type.
      Overrides:
      one in class Unit
      Returns:
      a measure of magnitude 1.0 in terms of this unit

    • mutable

      public MutableMeasure<? extends PerUnit<N,D>,?,?> mutable(double initialMagnitude)
      Creates a new mutable measurement that is initialized to the given magnitude in terms of this unit. Implementations are strongly recommended to sharpen the return type to a unit-specific measurement implementation.

      Note: When called on an object of type PerUnit (and not a subclass!), this method will always return a MutPer instance.

      Specified by:
      mutable in class Unit
      Parameters:
      initialMagnitude - the starting magnitude of the measure
      Returns:
      the ratio measure

    • mutableNative

      public final MutPer<N,D> mutableNative(double initialMagnitude)
      Creates a new mutable measurement of the given magnitude in terms of the ratio unit. This will always return a Per object and cannot be overridden by subclasses.
      Parameters:
      initialMagnitude - the starting magnitude of the measure
      Returns:
      the ratio measure
      See Also:

    • per

      public Unit per(TimeUnit time)
      Description copied from class: Unit
      Combines this unit with a unit of time. This often - but not always - results in a velocity. Subclasses should sharpen the return type to be unit-specific.
      Specified by:
      per in class Unit
      Parameters:
      time - the unit of time
      Returns:
      the combined unit

    • convertFrom

      public double convertFrom(double magnitude, PerUnit<? extends N,? extends D> otherUnit)
      Converts a measurement value in terms of another unit to this unit.
      Parameters:
      magnitude - the magnitude of the measurement in terms of the other unit
      otherUnit - the other unit
      Returns:
      the value of the measurement in terms of this unit

    • equals

      public boolean equals(Object o)
      Overrides:
      equals in class Unit

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Unit