tec.units.ri

Class AbstractQuantity<Q extends javax.measure.Quantity<Q>>

java.lang.Object

tec.units.ri.AbstractQuantity<Q>

All Implemented Interfaces:

Comparable<javax.measure.Quantity<Q>>, javax.measure.Quantity<Q>, tec.uom.lib.common.function.UnitSupplier<Q>, tec.uom.lib.common.function.ValueSupplier<Number>

Direct Known Subclasses:

NumberQuantity

public abstract class AbstractQuantity<Q extends javax.measure.Quantity<Q>>
extends Object
implements javax.measure.Quantity<Q>, Comparable<javax.measure.Quantity<Q>>, tec.uom.lib.common.function.UnitSupplier<Q>, tec.uom.lib.common.function.ValueSupplier<Number>

This class represents the immutable result of a scalar measurement stated in a known unit.

public static final Quantity C = NumberQuantity.parse("299792458 m/s").asType(Velocity.class); // Speed of Light (exact).

Quantities can be converted to different units.
Quantity milesPerHour = C.to(MILES_PER_HOUR); // Use double implementation (fast). System.out.println(milesPerHour); > 670616629.3843951 m/h

Applications may sub-class AbstractQuantity for particular quantity types.
// Quantity of type Mass based on double primitive types.
public class MassAmount extends AbstractQuantity {
private final double kilograms; // Internal SI representation.
private Mass(double kg) { kilograms = kg; }
public static Mass of(double value, Unit unit) {
return new Mass(unit.getConverterTo(SI.KILOGRAM).convert(value));
}
public Unit getUnit() { return SI.KILOGRAM; }
public Double getValue() { return _kilograms; }
...
}


// Complex numbers measurements.
public class ComplexQuantity extends AbstractQuantity {
public Complex getValue() { ... } // Assuming Complex is a Number.
...
}

// Specializations of complex numbers measurements.
public final class Current extends ComplexQuantity {...}
public final class Tension extends ComplexQuantity {...}


All instances of this class shall be immutable.

Version:

1.0, August 9, 2016

Author:

Werner Keil

Field Summary

Fields

Modifier and Type	Field and Description
static javax.measure.Quantity<javax.measure.quantity.Dimensionless>	NONE Holds a dimensionless quantity of none (exact).
static javax.measure.Quantity<javax.measure.quantity.Dimensionless>	ONE Holds a dimensionless quantity of one (exact).

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractQuantity(javax.measure.Unit<Q> unit) constructor.

Method Summary

Methods

Modifier and Type	Method and Description
<T extends javax.measure.Quantity<T>> AbstractQuantity<T>	asType(Class<T> type) Casts this quantity to a parameterized unit of specified nature or throw a ClassCastException if the dimension of the specified quantity and this measure unit's dimension do not match.
int	compareTo(javax.measure.Quantity<Q> that) Compares this measure to the specified Measurement quantity.
abstract double	doubleValue(javax.measure.Unit<Q> unit)
boolean	equals(AbstractQuantity<Q> that, double epsilon, javax.measure.Unit<Q> epsilonUnit) Compares this measure and the specified Measurement to the given accuracy.
boolean	equals(Object obj) Compares this measure against the specified object for strict equality (same unit and same amount).
protected float	floatValue(javax.measure.Unit<Q> unit)
javax.measure.Unit<Q>	getUnit() Returns the measurement unit.
abstract Number	getValue() Returns the measurement numeric value.
int	hashCode() Returns the hash code for this quantity.
protected long	longValue(javax.measure.Unit<Q> unit)
javax.measure.Quantity<Q>	to(javax.measure.Unit<Q> unit) Returns this measure after conversion to specified unit.
javax.measure.Quantity<Q>	toSI() Convenient method equivalent to to(this.getUnit().toSI()).
String	toString() Returns the String representation of this quantity.

Methods inherited from class java.lang.Object

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

Methods inherited from interface javax.measure.Quantity

add, divide, divide, inverse, multiply, multiply, subtract

Field Detail

NONE

public static final javax.measure.Quantity<javax.measure.quantity.Dimensionless> NONE

Holds a dimensionless quantity of none (exact).

ONE

public static final javax.measure.Quantity<javax.measure.quantity.Dimensionless> ONE

Holds a dimensionless quantity of one (exact).

Constructor Detail

AbstractQuantity

protected AbstractQuantity(javax.measure.Unit<Q> unit)

constructor.

Method Detail

getValue

public abstract Number getValue()

Returns the measurement numeric value.

Specified by:

getValue in interface javax.measure.Quantity<Q extends javax.measure.Quantity<Q>>

Specified by:

getValue in interface tec.uom.lib.common.function.ValueSupplier<Number>

Returns:

the measurement value.

getUnit

public javax.measure.Unit<Q> getUnit()

Returns the measurement unit.

Specified by:

getUnit in interface javax.measure.Quantity<Q extends javax.measure.Quantity<Q>>

Specified by:

getUnit in interface tec.uom.lib.common.function.UnitSupplier<Q extends javax.measure.Quantity<Q>>

Returns:

the measurement unit.

toSI

public javax.measure.Quantity<Q> toSI()

Convenient method equivalent to to(this.getUnit().toSI()).

Returns:

this measure or a new measure equivalent to this measure but stated in SI units.

Throws:

ArithmeticException - if the result is inexact and the quotient has a non-terminating decimal expansion.

to

public javax.measure.Quantity<Q> to(javax.measure.Unit<Q> unit)

Returns this measure after conversion to specified unit. The default implementation returns Measure.valueOf(doubleValue(unit), unit) . If this measure is already stated in the specified unit, then this measure is returned and no conversion is performed.

Specified by:

to in interface javax.measure.Quantity<Q extends javax.measure.Quantity<Q>>

Parameters:

unit - the unit in which the returned measure is stated.

Returns:

this measure or a new measure equivalent to this measure but stated in the specified unit.

Throws:

ArithmeticException - if the result is inexact and the quotient has a non-terminating decimal expansion.

compareTo

public int compareTo(javax.measure.Quantity<Q> that)

Compares this measure to the specified Measurement quantity. The default implementation compares the doubleValue(Unit) of both this measure and the specified Measurement stated in the same unit (this measure's unit).

Specified by:

compareTo in interface Comparable<javax.measure.Quantity<Q extends javax.measure.Quantity<Q>>>

Returns:

a negative integer, zero, or a positive integer as this measure is less than, equal to, or greater than the specified Measurement quantity.

See Also:

NaturalOrder}

equals

public boolean equals(Object obj)

Compares this measure against the specified object for strict equality (same unit and same amount).

Similarly to the BigDecimal#equals method which consider 2.0 and 2.00 as different objects because of different internal scales, measurements such as Measure.valueOf(3.0, KILOGRAM) Measure.valueOf(3, KILOGRAM) and Quantities.getQuantity("3 kg") might not be considered equals because of possible differences in their implementations.

To compare measures stated using different units or using different amount implementations the compareTo or equals(Measurement, epsilon, epsilonUnit) methods should be used.

Overrides:

equals in class Object

Parameters:

obj - the object to compare with.

Returns:

this.getUnit.equals(obj.getUnit()) && this.getValue().equals(obj.getValue())

equals

public boolean equals(AbstractQuantity<Q> that,
             double epsilon,
             javax.measure.Unit<Q> epsilonUnit)

Compares this measure and the specified Measurement to the given accuracy. Measurements are considered approximately equals if their absolute differences when stated in the same specified unit is less than the specified epsilon.

Parameters:

that - the Measurement to compare with.

epsilon - the absolute error stated in epsilonUnit.

epsilonUnit - the epsilon unit.

Returns:

abs(this.doubleValue(epsilonUnit) - that.doubleValue(epsilonUnit)) <= epsilon

hashCode

public int hashCode()

Returns the hash code for this quantity.

Overrides:

hashCode in class Object

Returns:

the hash code value.

toString

public String toString()

Returns the String representation of this quantity. The string produced for a given quantity is always the same; it is not affected by locale. This means that it can be used as a canonical string representation for exchanging quantity, or as a key for a Hashtable, etc. Locale-sensitive quantity formatting and parsing is handled by the QuantityFormat class and its subclasses.

Overrides:

toString in class Object

Returns:

UnitFormat.getInternational().format(this)

doubleValue

public abstract double doubleValue(javax.measure.Unit<Q> unit)
                            throws ArithmeticException

Throws:

ArithmeticException

longValue

protected long longValue(javax.measure.Unit<Q> unit)
                  throws ArithmeticException

Throws:

ArithmeticException

floatValue

protected float floatValue(javax.measure.Unit<Q> unit)

asType

public final <T extends javax.measure.Quantity<T>> AbstractQuantity<T> asType(Class<T> type)
                                                                   throws ClassCastException

Casts this quantity to a parameterized unit of specified nature or throw a ClassCastException if the dimension of the specified quantity and this measure unit's dimension do not match. For example:
Measure length = Quantities.getQuantity("2 km").asType(Length.class);

Specified by:

asType in interface javax.measure.Quantity<Q extends javax.measure.Quantity<Q>>

Parameters:

type - the quantity class identifying the nature of the quantity.

Returns:

this quantity parameterized with the specified type.

Throws:

ClassCastException - if the dimension of this unit is different from the specified quantity dimension.

UnsupportedOperationException - if the specified quantity class does not have a public static field named "UNIT" holding the SI unit for the quantity.

See Also:

Unit.asType(Class)