Energy.java
package org.djunits.quantity;
import org.djunits.quantity.def.Quantity;
import org.djunits.unit.AbstractUnit;
import org.djunits.unit.UnitRuntimeException;
import org.djunits.unit.Unitless;
import org.djunits.unit.Units;
import org.djunits.unit.scale.LinearScale;
import org.djunits.unit.scale.Scale;
import org.djunits.unit.si.SIUnit;
import org.djunits.unit.system.UnitSystem;
/**
* Energy is a physical quantity representing the capacity to do work, measured in joules (J).
* <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 Energy extends Quantity<Energy, Energy.Unit>
{
/** Constant with value zero. */
public static final Energy ZERO = Energy.ofSi(0.0);
/** Constant with value one. */
public static final Energy ONE = Energy.ofSi(1.0);
/** Constant with value NaN. */
@SuppressWarnings("checkstyle:constantname")
public static final Energy NaN = Energy.ofSi(Double.NaN);
/** Constant with value POSITIVE_INFINITY. */
public static final Energy POSITIVE_INFINITY = Energy.ofSi(Double.POSITIVE_INFINITY);
/** Constant with value NEGATIVE_INFINITY. */
public static final Energy NEGATIVE_INFINITY = Energy.ofSi(Double.NEGATIVE_INFINITY);
/** Constant with value MAX_VALUE. */
public static final Energy POS_MAXVALUE = Energy.ofSi(Double.MAX_VALUE);
/** Constant with value -MAX_VALUE. */
public static final Energy NEG_MAXVALUE = Energy.ofSi(-Double.MAX_VALUE);
/** */
private static final long serialVersionUID = 600L;
/**
* Instantiate a Energy quantity with a unit.
* @param value the value, expressed in the unit
* @param unit the unit in which the value is expressed
*/
public Energy(final double value, final Energy.Unit unit)
{
super(value, unit);
}
/**
* Instantiate a Energy quantity with a unit, expressed as a String.
* @param value the value, expressed in the unit
* @param abbreviation the String abbreviation of the unit in which the value is expressed
*/
public Energy(final double value, final String abbreviation)
{
this(value, Units.resolve(Energy.Unit.class, abbreviation));
}
/**
* Construct Energy quantity.
* @param value Scalar from which to construct this instance
*/
public Energy(final Energy value)
{
super(value.si(), Energy.Unit.SI);
setDisplayUnit(value.getDisplayUnit());
}
/**
* Return a Energy instance based on an SI value.
* @param si the si value
* @return the Energy instance based on an SI value
*/
public static Energy ofSi(final double si)
{
return new Energy(si, Energy.Unit.SI);
}
@Override
public Energy instantiate(final double si)
{
return ofSi(si);
}
@Override
public SIUnit siUnit()
{
return Energy.Unit.SI_UNIT;
}
/**
* Returns a Energy 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 Energy
* @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 Energy valueOf(final String text)
{
return Quantity.valueOf(text, ZERO);
}
/**
* Returns a Energy based on a value and the textual representation of the unit, which can be localized.
* @param value the value to use
* @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 Energy of(final double value, final String unitString)
{
return Quantity.of(value, unitString, ZERO);
}
/**
* Calculate the division of Energy and Energy, which results in a Dimensionless quantity.
* @param v quantity
* @return quantity as a division of Energy and Energy
*/
public final Dimensionless divide(final Energy v)
{
return new Dimensionless(this.si() / v.si(), Unitless.BASE);
}
/**
* Calculate the division of Energy and Force, which results in a Length scalar.
* @param v scalar
* @return scalar as a division of Energy and Force
*/
public final Length divide(final Force v)
{
return new Length(this.si() / v.si(), Length.Unit.SI);
}
/**
* Calculate the division of Energy and Length, which results in a Force scalar.
* @param v scalar
* @return scalar as a division of Energy and Length
*/
public final Force divide(final Length v)
{
return new Force(this.si() / v.si(), Force.Unit.SI);
}
/**
* Calculate the multiplication of Energy and LinearDensity, which results in a Force scalar.
* @param v scalar
* @return scalar as a multiplication of Energy and LinearDensity
*/
public final Force multiply(final LinearObjectDensity v)
{
return new Force(this.si() * v.si(), Force.Unit.SI);
}
/**
* Calculate the division of Energy and Duration, which results in a Power scalar.
* @param v scalar
* @return scalar as a division of Energy and Duration
*/
public final Power divide(final Duration v)
{
return new Power(this.si() / v.si(), Power.Unit.SI);
}
/**
* Calculate the division of Energy and Power, which results in a Duration scalar.
* @param v scalar
* @return scalar as a division of Energy and Power
*/
public final Duration divide(final Power v)
{
return new Duration(this.si() / v.si(), Duration.Unit.SI);
}
/**
* Calculate the division of Energy and Volume, which results in a Pressure scalar.
* @param v scalar
* @return scalar as a division of Energy and Volume
*/
public final Pressure divide(final Volume v)
{
return new Pressure(this.si() / v.si(), Pressure.Unit.SI);
}
/**
* Calculate the division of Energy and Pressure, which results in a Volume scalar.
* @param v scalar
* @return scalar as a division of Energy and Pressure
*/
public final Volume divide(final Pressure v)
{
return new Volume(this.si() / v.si(), Volume.Unit.SI);
}
/**
* Calculate the multiplication of Energy and Frequency, which results in a Power scalar.
* @param v scalar
* @return scalar as a multiplication of Energy and Frequency
*/
public final Power multiply(final Frequency v)
{
return new Power(this.si() * v.si(), Power.Unit.SI);
}
/**
* Calculate the division of Energy and Speed, which results in a Momentum scalar.
* @param v scalar
* @return scalar as a division of Energy and Speed
*/
public final Momentum divide(final Speed v)
{
return new Momentum(this.si() / v.si(), Momentum.Unit.SI);
}
/**
* Calculate the division of Energy and Momentum, which results in a Speed scalar.
* @param v scalar
* @return scalar as a division of Energy and Momentum
*/
public final Speed divide(final Momentum v)
{
return new Speed(this.si() / v.si(), Speed.Unit.SI);
}
/******************************************************************************************************/
/********************************************** UNIT CLASS ********************************************/
/******************************************************************************************************/
/**
* Energy.Unit encodes the units of energy.
* <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<Energy.Unit, Energy>
{
/** The dimensions of energy: kgm2/s2. */
public static final SIUnit SI_UNIT = SIUnit.of("kgm2/s2");
/** Joule. */
public static final Energy.Unit J = new Energy.Unit("J", "joule", 1.0, UnitSystem.SI_DERIVED);
/** The SI or BASE unit. */
public static final Energy.Unit SI = J.generateSiPrefixes(false, false);
/** microjoule. */
public static final Energy.Unit muJ = Units.resolve(Energy.Unit.class, "muJ");
/** millijoule. */
public static final Energy.Unit mJ = Units.resolve(Energy.Unit.class, "mJ");
/** kilojoule. */
public static final Energy.Unit kJ = Units.resolve(Energy.Unit.class, "kJ");
/** megajoule. */
public static final Energy.Unit MJ = Units.resolve(Energy.Unit.class, "MJ");
/** gigajoule. */
public static final Energy.Unit GJ = Units.resolve(Energy.Unit.class, "GJ");
/** terajoule. */
public static final Energy.Unit TJ = Units.resolve(Energy.Unit.class, "TJ");
/** petajoule. */
public static final Energy.Unit PJ = Units.resolve(Energy.Unit.class, "PJ");
/** foot-pound force. */
public static final Energy.Unit ft_lbf = J.deriveUnit("ft.lbf", "foot pound-force",
Length.Unit.CONST_FT * Mass.Unit.CONST_LB * Acceleration.Unit.CONST_GRAVITY, UnitSystem.IMPERIAL);
/** inch-pound force. */
public static final Energy.Unit in_lbf = J.deriveUnit("in.lbf", "inch pound-force",
Length.Unit.CONST_IN * Mass.Unit.CONST_LB * Acceleration.Unit.CONST_GRAVITY, UnitSystem.IMPERIAL);
/** British thermal unit (ISO). */
public static final Energy.Unit BTU_ISO =
J.deriveUnit("BTU(ISO)", "British thermal unit (ISO)", 1.0545E3, UnitSystem.IMPERIAL);
/** British thermal unit (International Table). */
public static final Energy.Unit BTU_IT =
J.deriveUnit("BTU(IT)", "British thermal unit (Int. Table)", 1.05505585262E3, UnitSystem.IMPERIAL);
/** calorie (International Table). */
public static final Energy.Unit cal_IT = J.deriveUnit("cal(IT)", "calorie (Int. Table)", 4.1868, UnitSystem.IMPERIAL);
/** calorie. */
public static final Energy.Unit cal = J.deriveUnit("cal", "calorie", 4.184, UnitSystem.OTHER);
/** kilocalorie. */
public static final Energy.Unit kcal = cal.deriveUnit("kcal", "kilocalorie", 1000.0, UnitSystem.OTHER);
/** watt hour. */
public static final Energy.Unit WATT_HOUR = new Energy.Unit("Wh", "watt hour", 3600.0, UnitSystem.SI_DERIVED);
/** microwatt hour. */
public static final Energy.Unit muWh =
WATT_HOUR.deriveUnit("muWh", "\u03BCWh", "microwatt hour", 1E-6, UnitSystem.SI_DERIVED);
/** milliwatt hour. */
public static final Energy.Unit mWh = WATT_HOUR.deriveUnit("mWh", "milliwatt hour", 1E-3, UnitSystem.SI_DERIVED);
/** kilowatt hour. */
public static final Energy.Unit kWh = WATT_HOUR.deriveUnit("kWh", "kilowatt hour", 1E3, UnitSystem.SI_DERIVED);
/** megawatt hour. */
public static final Energy.Unit MWh = WATT_HOUR.deriveUnit("MWh", "megawatt hour", 1E6, UnitSystem.SI_DERIVED);
/** gigawatt hour. */
public static final Energy.Unit GWh = WATT_HOUR.deriveUnit("GWh", "gigawatt hour", 1E9, UnitSystem.SI_DERIVED);
/** terawatt hour. */
public static final Energy.Unit TWh = WATT_HOUR.deriveUnit("TWh", "terawatt hour", 1E12, UnitSystem.SI_DERIVED);
/** petawatt hour. */
public static final Energy.Unit PWh = WATT_HOUR.deriveUnit("PWh", "petawatt hour", 1E15, UnitSystem.SI_DERIVED);
/** electronvolt. */
public static final Energy.Unit eV = new Energy.Unit("eV", "electronvolt", 1.602176634E-19, UnitSystem.SI_ACCEPTED);
/** kilo-electronvolt. */
public static final Energy.Unit keV = eV.deriveUnit("keV", "kiloelectronvolt", 1E3, UnitSystem.SI_ACCEPTED);
/** mega-electronvolt. */
public static final Energy.Unit MeV = eV.deriveUnit("MeV", "megaelectronvolt", 1E6, UnitSystem.SI_ACCEPTED);
/** giga-electronvolt. */
public static final Energy.Unit GeV = eV.deriveUnit("GeV", "gigaelectronvolt", 1E9, UnitSystem.SI_ACCEPTED);
/** sthene-meter (mts). */
public static final Energy.Unit sn_m = J.deriveUnit("sn.m", "sthene meter", 1000.0, UnitSystem.MTS);
/** erg (cgs). */
public static final Energy.Unit erg = J.deriveUnit("erg", "erg", 1.0E-7, UnitSystem.CGS);
/**
* Create a new Energy 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, new LinearScale(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 between this unit and the standard (e.g., SI, BASE) unit
* @param unitSystem unit system, e.g. SI or Imperial
*/
public Unit(final String textualAbbreviation, final String displayAbbreviation, final String name, final Scale scale,
final UnitSystem unitSystem)
{
super(textualAbbreviation, displayAbbreviation, name, scale, unitSystem);
}
@Override
public SIUnit siUnit()
{
return SI_UNIT;
}
@Override
public Unit getBaseUnit()
{
return SI;
}
@Override
public Energy ofSi(final double si)
{
return Energy.ofSi(si);
}
@Override
public Unit deriveUnit(final String textualAbbreviation, final String displayAbbreviation, final String name,
final double scaleFactor, final UnitSystem unitSystem)
{
if (getScale() instanceof LinearScale ls)
{
return new Energy.Unit(textualAbbreviation, displayAbbreviation, name,
new LinearScale(ls.getScaleFactorToBaseUnit() * scaleFactor), unitSystem);
}
throw new UnitRuntimeException("Only possible to derive a unit from a unit with a linear scale");
}
}
}