Pressure.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;
/**
* Pressure is the force exerted per unit area, measured in pascals (Pa).
* <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 Pressure extends Quantity<Pressure, Pressure.Unit>
{
/** Constant with value zero. */
public static final Pressure ZERO = Pressure.ofSi(0.0);
/** Constant with value one. */
public static final Pressure ONE = Pressure.ofSi(1.0);
/** Constant with value NaN. */
@SuppressWarnings("checkstyle:constantname")
public static final Pressure NaN = Pressure.ofSi(Double.NaN);
/** Constant with value POSITIVE_INFINITY. */
public static final Pressure POSITIVE_INFINITY = Pressure.ofSi(Double.POSITIVE_INFINITY);
/** Constant with value NEGATIVE_INFINITY. */
public static final Pressure NEGATIVE_INFINITY = Pressure.ofSi(Double.NEGATIVE_INFINITY);
/** Constant with value MAX_VALUE. */
public static final Pressure POS_MAXVALUE = Pressure.ofSi(Double.MAX_VALUE);
/** Constant with value -MAX_VALUE. */
public static final Pressure NEG_MAXVALUE = Pressure.ofSi(-Double.MAX_VALUE);
/** */
private static final long serialVersionUID = 600L;
/**
* Instantiate a Pressure quantity with a unit.
* @param value the value, expressed in the unit
* @param unit the unit in which the value is expressed
*/
public Pressure(final double value, final Pressure.Unit unit)
{
super(value, unit);
}
/**
* Instantiate a Pressure 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 Pressure(final double value, final String abbreviation)
{
this(value, Units.resolve(Pressure.Unit.class, abbreviation));
}
/**
* Construct Pressure quantity.
* @param value Scalar from which to construct this instance
*/
public Pressure(final Pressure value)
{
super(value.si(), Pressure.Unit.SI);
setDisplayUnit(value.getDisplayUnit());
}
/**
* Return a Pressure instance based on an SI value.
* @param si the si value
* @return the Pressure instance based on an SI value
*/
public static Pressure ofSi(final double si)
{
return new Pressure(si, Pressure.Unit.SI);
}
@Override
public Pressure instantiate(final double si)
{
return ofSi(si);
}
@Override
public SIUnit siUnit()
{
return Pressure.Unit.SI_UNIT;
}
/**
* Returns a Pressure 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 Pressure
* @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 Pressure valueOf(final String text)
{
return Quantity.valueOf(text, ZERO);
}
/**
* Returns a Pressure 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 Pressure of(final double value, final String unitString)
{
return Quantity.of(value, unitString, ZERO);
}
/**
* Calculate the division of Pressure and Pressure, which results in a Dimensionless quantity.
* @param v quantity
* @return quantity as a division of Pressure and Pressure
*/
public final Dimensionless divide(final Pressure v)
{
return new Dimensionless(this.si() / v.si(), Unitless.BASE);
}
/**
* Calculate the multiplication of Pressure and Area, which results in a Force scalar.
* @param v scalar
* @return scalar as a multiplication of Pressure and Area
*/
public final Force multiply(final Area v)
{
return new Force(this.si() * v.si(), Force.Unit.SI);
}
/**
* Calculate the multiplication of Pressure and Volume, which results in a Energy scalar.
* @param v scalar
* @return scalar as a multiplication of Pressure and Volume
*/
public final Energy multiply(final Volume v)
{
return new Energy(this.si() * v.si(), Energy.Unit.SI);
}
/******************************************************************************************************/
/********************************************** UNIT CLASS ********************************************/
/******************************************************************************************************/
/**
* Pressure.Unit encodes the units of force exerted per unit area.
* <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<Pressure.Unit, Pressure>
{
/** The dimensions of pressure: kg/m.s2. */
public static final SIUnit SI_UNIT = SIUnit.of("kg/ms2");
/** Pascal. */
public static final Pressure.Unit Pa = new Pressure.Unit("Pa", "pascal", 1.0, UnitSystem.SI_DERIVED);
/** The SI or BASE unit. */
public static final Pressure.Unit SI = Pa.generateSiPrefixes(false, false);
/** hectopascal. */
public static final Pressure.Unit hPa = Units.resolve(Pressure.Unit.class, "hPa");
/** kilopascal. */
public static final Pressure.Unit kPa = Units.resolve(Pressure.Unit.class, "kPa");
/** standard atmosphere. */
public static final Pressure.Unit atm = Pa.deriveUnit("atm", "atmosphere (standard)", 101325.0, UnitSystem.OTHER);
/** torr. */
public static final Pressure.Unit torr = atm.deriveUnit("torr", "Torr", 1.0 / 760.0, UnitSystem.OTHER);
/** technical atmosphere = kgf/cm2. */
public static final Pressure.Unit at =
Pa.deriveUnit("at", "atmosphere (technical)", Acceleration.Unit.CONST_GRAVITY / 1.0E-4, UnitSystem.OTHER);
/** barye = dyne/cm2. */
public static final Pressure.Unit Ba = Pa.deriveUnit("Ba", "barye", 1.0E-5 / 1.0E-4, UnitSystem.CGS);
/** bar. */
public static final Pressure.Unit bar = Pa.deriveUnit("bar", "bar", 1.0E5, UnitSystem.OTHER);
/** millibar. */
public static final Pressure.Unit mbar = bar.deriveUnit("mbar", "millibar", 1.0E-3, UnitSystem.OTHER);
/** cm Hg. */
public static final Pressure.Unit cmHg = Pa.deriveUnit("cmHg", "centimeter mercury", 1333.224, UnitSystem.OTHER);
/** mm Hg. */
public static final Pressure.Unit mmHg = Pa.deriveUnit("mmHg", "millimeter mercury", 133.3224, UnitSystem.OTHER);
/** foot Hg. */
public static final Pressure.Unit ftHg = Pa.deriveUnit("ftHg", "foot mercury", 40.63666E3, UnitSystem.IMPERIAL);
/** inch Hg. */
public static final Pressure.Unit inHg = Pa.deriveUnit("inHg", "inch mercury", 3.386389E3, UnitSystem.IMPERIAL);
/** kilogram-force per square millimeter. */
public static final Pressure.Unit kgf_mm2 = Pa.deriveUnit("kgf/mm2", "kilogram-force per square millimeter",
Acceleration.Unit.CONST_GRAVITY / 1.0E-6, UnitSystem.OTHER);
/** pound-force per square foot. */
public static final Pressure.Unit lbf_ft2 = Pa.deriveUnit("lbf/ft2", "pound-force per square foot",
Mass.Unit.CONST_LB * Acceleration.Unit.CONST_GRAVITY / (Length.Unit.CONST_FT * Length.Unit.CONST_FT),
UnitSystem.IMPERIAL);
/** pound-force per square inch. */
public static final Pressure.Unit lbf_in2 = Pa.deriveUnit("lbf/in2", "pound-force per square inch",
Mass.Unit.CONST_LB * Acceleration.Unit.CONST_GRAVITY / (Length.Unit.CONST_IN * Length.Unit.CONST_IN),
UnitSystem.IMPERIAL);
/** psi = pound-force per square inch. */
public static final Pressure.Unit psi = lbf_in2;
/** pieze. */
public static final Pressure.Unit pz = Pa.deriveUnit("pz", "pi\u00E8ze", 1000.0, UnitSystem.MTS);
/**
* Create a new Pressure 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 Pressure ofSi(final double si)
{
return Pressure.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 Pressure.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");
}
}
}