# Class Quantities

Object
Quantities

public final class Quantities extends Object
Provides static methods working on `Quantity` instances. Apache SIS implementation of quantities has the following characteristics:

- Values are stored with `double` precision.
- All quantities implement the specific subtype (e.g. `Length` instead of `Quantity<Length>`).
- Quantities are immutable, `Comparable` and `Serializable`.

Since:
  0.8

- ## Method Summary

  Modifier and Type
  Method
  Description
  `static <Q extends Quantity<Q>>
  Q`
  `castOrCopy(Quantity<Q> quantity)`
  Returns the given quantity as an instance of the specific `Quantity` subtype.
  `static Quantity<?>`
  `create(double value, String unit)`
  Creates a quantity for the given value and unit of measurement symbol.
  `static <Q extends Quantity<Q>>
  Q`
  `create(double value, Unit<Q> unit)`
  Creates a quantity for the given value and unit of measurement.
  `static <Q extends Quantity<Q>>
  Quantity<Q>`
  `max(Quantity<Q> q1, Quantity<Q> q2)`
  Returns the largest of two quantities.
  `static <Q extends Quantity<Q>>
  Quantity<Q>`
  `min(Quantity<Q> q1, Quantity<Q> q2)`
  Returns the smallest of two quantities.

  ### Methods inherited from class Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- ## Method Details

  - ### create

    public static Quantity<?> create(double value, String unit)
    Creates a quantity for the given value and unit of measurement symbol. This is a convenience method that combines a call to `Units​.valueOf(String)` with `create(double, Unit)`.
    Parameters:
      `value` - the quantity magnitude.
      `unit` - symbol of the unit of measurement associated to the given value.
    Returns:
      a quantity of the given type for the given value and unit of measurement.
    Throws:
      `MeasurementParseException` - if the given symbol cannot be parsed.

  - ### create

    public static <Q extends Quantity<Q>> Q create(double value, Unit<Q> unit)
    Creates a quantity for the given value and unit of measurement.
    Type Parameters:
      `Q` - the quantity type (e.g. `Length`, `Angle`, `Time`, etc.).
    Parameters:
      `value` - the quantity magnitude.
      `unit` - the unit of measurement associated to the given value.
    Returns:
      a quantity of the given type for the given value and unit of measurement.
    Throws:
      `IllegalArgumentException` - if the given unit class is not a supported implementation.
    See Also:
      - `UnitServices​.getQuantityFactory(Class)`

  - ### castOrCopy

    public static <Q extends Quantity<Q>> Q castOrCopy(Quantity<Q> quantity)
    Returns the given quantity as an instance of the specific `Quantity` subtype. For example, this method can be used for converting a `Quantity<Length>` to a `Length`. If the given quantity already implements the specific interface, then it is returned as-is.
    Type Parameters:
      `Q` - the quantity type (e.g. `Length`, `Angle`, `Time`, etc.), or `null`.
    Parameters:
      `quantity` - the quantity to convert to the specific subtype.
    Returns:
      the given quantity as a specific subtype (may be `quantity` itself), or `null` if the given quantity was null.
    Throws:
      `IllegalArgumentException` - if the unit class associated to the given quantity is not a supported implementation.

  - ### min

    public static <Q extends Quantity<Q>> Quantity<Q> min(Quantity<Q> q1, Quantity<Q> q2)
    Returns the smallest of two quantities. Values are converted to system unit before to be compared. If one of the two quantities is `null` or has NaN value, then the other quantity is returned. If the two quantities have equal converted values, then the first quantity is returned.
    Type Parameters:
      `Q` - type of quantities.
    Parameters:
      `q1` - the first quantity (can be `null`).
      `q2` - the second quantity (can be `null`).
    Returns:
      the smallest of the two given quantities.
    Since:
      1.1

  - ### max

    public static <Q extends Quantity<Q>> Quantity<Q> max(Quantity<Q> q1, Quantity<Q> q2)
    Returns the largest of two quantities. Values are converted to system unit before to be compared. If one of the two quantities is `null` or has NaN value, then the other quantity is returned. If the two quantities have equal converted values, then the first quantity is returned.
    Type Parameters:
      `Q` - type of quantities.
    Parameters:
      `q1` - the first quantity (can be `null`).
      `q2` - the second quantity (can be `null`).
    Returns:
      the largest of the two given quantities.
    Since:
      1.1