Units of Measurement Reference Implementation 2.2.2 · tech.units.indriya

This package provides the Reference Implementation of the Units of Measurement API.

Usage:

import javax.measure.quantity.*; // Holds quantity types.
import static javax.measure.MetricPrefix.*;

import tech.units.indriya.AbstractUnit;
import tech.units.indriya.function.AbstractConverter;

import static tech.units.indriya.unit.Units.*; // Standard CommonUnits.
import static system.uom.common.USCustomary.MILE; // Non-standard unit.

public class Main {
    public void main(String[] args) {

        // Conversion between units (explicit way).
        AbstractUnit<Length> sourceUnit = KILO(METRE);
        AbstractUnit<Length> targetUnit = MILE;
        UnitConverter uc = sourceUnit.getConverterTo(targetUnit);
        System.out.println(uc.convert(10)); // Converts 10 km to miles.

        // Same conversion than above, packed in one line.
        System.out.println(KILO(METRE).getConverterTo(MILE).convert(10));

        // Retrieval of the SI unit (identifies the measurement type).
        System.out.println(REVOLUTION.divide(MINUTE).toSI());

        // Dimension checking (allows/disallows conversions)
        System.out.println(ELECTRON_VOLT.isCompatible(WATT.times(HOUR)));

        // Retrieval of the unit dimension (depends upon the current model).
        System.out.println(ELECTRON_VOLT.getDimension());
    }
}

> 6.2137119223733395
> 6.2137119223733395
> rad/s
> true
> [L]²·[M]/[T]²

Unit Parameterization

CommonUnits are parameterized enforce compile-time checks of units/measures consistency, for example:

Unit<Time> MINUTE = SECOND.multiply(60); // Ok.
    Unit<Time> MINUTE = METRE.multiply(60); // Compile error.

    Unit<Pressure> HECTOPASCAL = HECTO(PASCAL); // Ok.
    Unit<Pressure> HECTOPASCAL = HECTO(NEWTON); // Compile error.

    Quantity<Time> duration = Quantities.getQuantity(2, MINUTE); // Ok.
    Quantity<Time> duration = Quantities.getQuantity(2, CELSIUS); // Compile error.

Runtime checks of dimension consistency can be done for more complex cases.

Unit<Area> SQUARE_METRE = METRE.times(METRE).asType(Area.class); // Ok.
    Unit<Area> SQUARE_METRE = METRE.times(KELVIN).asType(Area.class); // Runtime error.

    Unit<Temperature> KELVIN = AbstractUnit.parse("K").asType(Temperature.class); // Ok.
    Unit<Temperature> KELVIN = AbstractUnit.parse("kg").asType(Temperature.class); // Runtime error.

Modifier and Type	Interface and Description
public interface	ComparableQuantity< the quantity type Q extends Quantity<Q>> Quantity that adapts Comparable to the `Quantity` interface.

Class Summary

Modifier and Type	Class and Description
public abstract class	AbstractQuantity<Q extends Quantity<Q>> This class represents the immutable result of a scalar quantity stated in a known unit.
public abstract class	AbstractSystemOfUnits An abstract base class for unit systems.
public abstract class	AbstractUnit<Q extends Quantity<Q>> The class represents units founded on the seven SI base units for seven base quantities assumed to be mutually independent.

Package tech.units.indriya

Usage:

Unit Parameterization

Interface Summary

Class Summary