LinearObjectDensity.java
package org.djunits.quantity;
import org.djunits.quantity.def.Quantity;
import org.djunits.unit.AbstractUnit;
import org.djunits.unit.UnitInterface;
import org.djunits.unit.UnitRuntimeException;
import org.djunits.unit.Unitless;
import org.djunits.unit.Units;
import org.djunits.unit.scale.IdentityScale;
import org.djunits.unit.scale.LinearScale;
import org.djunits.unit.scale.Scale;
import org.djunits.unit.si.SIPrefix;
import org.djunits.unit.si.SIPrefixes;
import org.djunits.unit.si.SIUnit;
import org.djunits.unit.system.UnitSystem;
/**
* Linear object density counts the number of objects per unit of length, measured in number per meter (/m).
* <p>
* Copyright (c) 2025-2026 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved. See
* for project information <a href="https://djunits.org" target="_blank">https://djunits.org</a>. The DJUNITS project is
* distributed under a <a href="https://djunits.org/docs/license.html" target="_blank">three-clause BSD-style license</a>.
* @author Alexander Verbraeck
*/
public class LinearObjectDensity extends Quantity<LinearObjectDensity>
{
/** Constant with value zero. */
public static final LinearObjectDensity ZERO = ofSi(0.0);
/** Constant with value one. */
public static final LinearObjectDensity ONE = ofSi(1.0);
/** Constant with value NaN. */
@SuppressWarnings("checkstyle:constantname")
public static final LinearObjectDensity NaN = ofSi(Double.NaN);
/** Constant with value POSITIVE_INFINITY. */
public static final LinearObjectDensity POSITIVE_INFINITY = ofSi(Double.POSITIVE_INFINITY);
/** Constant with value NEGATIVE_INFINITY. */
public static final LinearObjectDensity NEGATIVE_INFINITY = ofSi(Double.NEGATIVE_INFINITY);
/** Constant with value MAX_VALUE. */
public static final LinearObjectDensity POS_MAXVALUE = ofSi(Double.MAX_VALUE);
/** Constant with value -MAX_VALUE. */
public static final LinearObjectDensity NEG_MAXVALUE = ofSi(-Double.MAX_VALUE);
/** */
private static final long serialVersionUID = 600L;
/**
* Instantiate a LinearObjectDensity quantity with an SI or base value and a display unit.
* @param value the quantity value expressed in the SI or base unit
* @param displayUnit the display unit to use
* @param useSi use SI value when true, use value in unit when false
*/
public LinearObjectDensity(final double value, final LinearObjectDensity.Unit displayUnit, final boolean useSi)
{
super(value, displayUnit, useSi);
}
/**
* Instantiate a LinearObjectDensity quantity expressed in the given unit.
* @param valueInUnit the quantity value expressed in the given unit
* @param unit the unit of the value, also acts as the display unit
*/
public LinearObjectDensity(final double valueInUnit, final LinearObjectDensity.Unit unit)
{
this(valueInUnit, unit, false);
}
/**
* Return a LinearObjectDensity instance based on an SI value.
* @param si the si value
* @return the LinearObjectDensity instance based on an SI value
*/
public static LinearObjectDensity ofSi(final double si)
{
return new LinearObjectDensity(si, LinearObjectDensity.Unit.SI, true);
}
/**
* Instantiate a LinearObjectDensity quantity with an SI or base value and a display unit.
* @param siValue the quantity value expressed in the SI or base unit
* @param displayUnit the display unit to use
* @return the LinearObjectDensity instance based on an SI value with the given display unit
*/
public static LinearObjectDensity ofSi(final double siValue, final LinearObjectDensity.Unit displayUnit)
{
return new LinearObjectDensity(siValue, displayUnit, true);
}
@Override
public LinearObjectDensity instantiateSi(final double siValue, final UnitInterface<LinearObjectDensity> displayUnit)
{
return new LinearObjectDensity(siValue, (LinearObjectDensity.Unit) displayUnit, true);
}
/**
* Returns a LinearObjectDensity representation of a textual representation of a value with a unit. The String
* representation that can be parsed is the double value in the unit, followed by a localized or English abbreviation of the
* unit. Spaces are allowed, but not required, between the value and the unit.
* @param text the textual representation to parse into a LinearObjectDensity
* @return the Scalar representation of the value in its unit
* @throws IllegalArgumentException when the text cannot be parsed
* @throws NullPointerException when the text argument is null
*/
public static LinearObjectDensity valueOf(final String text)
{
return Quantity.valueOf(text, ZERO);
}
/**
* Returns a LinearObjectDensity based on a value expressed in the unit.
* @param valueInUnit the value, expressed in the given unit
* @param unit the unit of the value, also acts as the display unit
* @return ab LinearObjectDensity representation of the value in its unit
*/
public static LinearObjectDensity of(final double valueInUnit, final LinearObjectDensity.Unit unit)
{
return new LinearObjectDensity(valueInUnit, unit);
}
/**
* Returns a LinearObjectDensity based on a value and the textual representation of the unit, which can be localized.
* @param valueInUnit the value, expressed in the unit as given by unitString
* @param unitString the textual representation of the unit
* @return the Scalar representation of the value in its unit
* @throws IllegalArgumentException when the unit cannot be parsed or is incorrect
* @throws NullPointerException when the unitString argument is null
*/
public static LinearObjectDensity of(final double valueInUnit, final String unitString)
{
return Quantity.of(valueInUnit, unitString, ZERO);
}
@Override
public LinearObjectDensity.Unit getDisplayUnit()
{
return (LinearObjectDensity.Unit) super.getDisplayUnit();
}
/**
* Calculate the division of LinearObjectDensity and LinearObjectDensity, which results in a Dimensionless quantity.
* @param v quantity
* @return quantity as a division of LinearObjectDensity and LinearObjectDensity
*/
public Dimensionless divide(final LinearObjectDensity v)
{
return new Dimensionless(this.si() / v.si(), Unitless.BASE);
}
/**
* Calculate the multiplication of LinearObjectDensity and Length, which results in a Dimensionless scalar.
* @param v scalar
* @return scalar as a multiplication of LinearObjectDensity and Length
*/
public Dimensionless multiply(final Length v)
{
return new Dimensionless(this.si() * v.si(), Unitless.BASE);
}
/**
* Calculate the multiplication of LinearObjectDensity and Area, which results in a Length scalar.
* @param v scalar
* @return scalar as a multiplication of LinearObjectDensity and Area
*/
public Length multiply(final Area v)
{
return new Length(this.si() * v.si(), Length.Unit.SI);
}
/**
* Calculate the multiplication of LinearObjectDensity and Energy, which results in a Force scalar.
* @param v scalar
* @return scalar as a multiplication of LinearObjectDensity and Energy
*/
public Force multiply(final Energy v)
{
return new Force(this.si() * v.si(), Force.Unit.SI);
}
/**
* Calculate the multiplication of LinearObjectDensity and Speed, which results in a Frequency scalar.
* @param v scalar
* @return scalar as a multiplication of LinearObjectDensity and Speed
*/
public Frequency multiply(final Speed v)
{
return new Frequency(this.si() * v.si(), Frequency.Unit.SI);
}
@Override
public Length reciprocal()
{
return Length.ofSi(1.0 / this.si());
}
/******************************************************************************************************/
/********************************************** UNIT CLASS ********************************************/
/******************************************************************************************************/
/**
* LinearObjectDensity.Unit encodes the unit for the number of objects per unit of length.
* <p>
* Copyright (c) 2025-2026 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved.
* See for project information <a href="https://djunits.org" target="_blank">https://djunits.org</a>. The DJUNITS project is
* distributed under a <a href="https://djunits.org/docs/license.html" target="_blank">three-clause BSD-style license</a>.
* @author Alexander Verbraeck
*/
@SuppressWarnings("checkstyle:constantname")
public static class Unit extends AbstractUnit<LinearObjectDensity>
{
/** The dimensions of the number of objects per unit of length: per meter (/m). */
public static final SIUnit SI_UNIT = SIUnit.of("/m");
/** per meter. */
public static final LinearObjectDensity.Unit per_m = new LinearObjectDensity.Unit("/m", "/m", "per meter",
IdentityScale.SCALE, UnitSystem.SI_DERIVED, SIPrefixes.getSiPrefixPer("/"));
/** The SI or BASE unit. */
public static final LinearObjectDensity.Unit SI = (Unit) per_m.generateSiPrefixes(false, true);
/** per millimeter. */
public static final LinearObjectDensity.Unit per_mm = Units.resolve(LinearObjectDensity.Unit.class, "/mm");
/** per centimeter. */
public static final LinearObjectDensity.Unit per_cm = Units.resolve(LinearObjectDensity.Unit.class, "/cm");
/** per decimeter. */
public static final LinearObjectDensity.Unit per_dm = Units.resolve(LinearObjectDensity.Unit.class, "/dm");
/** per decameter. */
public static final LinearObjectDensity.Unit per_dam = Units.resolve(LinearObjectDensity.Unit.class, "/dam");
/** per hectometer. */
public static final LinearObjectDensity.Unit per_hm = Units.resolve(LinearObjectDensity.Unit.class, "/hm");
/** per kilometer. */
public static final LinearObjectDensity.Unit per_km = Units.resolve(LinearObjectDensity.Unit.class, "/km");
/** per inch. */
public static final LinearObjectDensity.Unit per_in =
new LinearObjectDensity.Unit("/in", "per inch", 1.0 / Length.Unit.CONST_IN, UnitSystem.IMPERIAL);
/** per foot. */
public static final LinearObjectDensity.Unit per_ft =
new LinearObjectDensity.Unit("/ft", "per foot", 1.0 / Length.Unit.CONST_FT, UnitSystem.IMPERIAL);
/** per yard. */
public static final LinearObjectDensity.Unit per_yd =
new LinearObjectDensity.Unit("/yd", "per yard", 1.0 / Length.Unit.CONST_YD, UnitSystem.IMPERIAL);
/** per mile. */
public static final LinearObjectDensity.Unit per_mi =
new LinearObjectDensity.Unit("/mi", "per mile", 1.0 / Length.Unit.CONST_MI, UnitSystem.IMPERIAL);
/**
* Create a new LinearObjectDensity unit.
* @param id the id or main abbreviation of the unit
* @param name the full name of the unit
* @param scaleFactorToBaseUnit the scale factor of the unit to convert it TO the base (SI) unit
* @param unitSystem the unit system such as SI or IMPERIAL
*/
public Unit(final String id, final String name, final double scaleFactorToBaseUnit, final UnitSystem unitSystem)
{
super(id, name, scaleFactorToBaseUnit, unitSystem);
}
/**
* Return a derived unit for this unit, with textual abbreviation(s) and a display abbreviation.
* @param textualAbbreviation the textual abbreviation of the unit, which doubles as the id
* @param displayAbbreviation the display abbreviation of the unit
* @param name the full name of the unit
* @param scale the scale to use to convert from this unit to the standard (e.g., SI, BASE) unit
* @param unitSystem unit system, e.g. SI or Imperial
* @param siPrefix the SI Prefix of this unit
*/
public Unit(final String textualAbbreviation, final String displayAbbreviation, final String name, final Scale scale,
final UnitSystem unitSystem, final SIPrefix siPrefix)
{
super(textualAbbreviation, displayAbbreviation, name, scale, unitSystem, siPrefix);
}
@Override
public SIUnit siUnit()
{
return SI_UNIT;
}
@Override
public Unit getBaseUnit()
{
return SI;
}
@Override
public LinearObjectDensity ofSi(final double si, final UnitInterface<LinearObjectDensity> displayUnit)
{
return new LinearObjectDensity(si, (Unit) displayUnit, true);
}
@Override
public LinearObjectDensity.Unit deriveUnit(final String textualAbbreviation, final String displayAbbreviation,
final String name, final double scaleFactor, final UnitSystem unitSystem, final SIPrefix siPrefix)
{
if (getScale() instanceof LinearScale ls)
{
return new LinearObjectDensity.Unit(textualAbbreviation, displayAbbreviation, name,
new LinearScale(ls.getScaleFactorToBaseUnit() * scaleFactor), unitSystem, siPrefix);
}
throw new UnitRuntimeException("Only possible to derive a unit from a unit with a linear scale");
}
}
}