Angle.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.GradeScale;
import org.djunits.unit.scale.IdentityScale;
import org.djunits.unit.scale.LinearScale;
import org.djunits.unit.scale.Scale;
import org.djunits.unit.si.SIUnit;
import org.djunits.unit.system.UnitSystem;
/**
* Angle is the measure of rotation between two intersecting lines, expressed in radians (rad) or degrees.
* <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 Angle extends Quantity<Angle, Angle.Unit>
{
/** Constant with value zero radians. */
public static final Angle ZERO = Angle.ofSi(0.0);
/** Constant with value pi radians. */
public static final Angle PI = Angle.ofSi(Math.PI);
/** Constant with value pi/2 radians. */
public static final Angle HALF_PI = Angle.ofSi(Math.PI / 2.0);
/** Constant with value 2 pi radians. */
public static final Angle TWO_PI = Angle.ofSi(Math.PI * 2.0);
/** Constant with value tau radians. */
public static final Angle TAU = Angle.ofSi(Math.PI * 2.0);
/** Constant with value one radian. */
public static final Angle ONE = Angle.ofSi(1.0);
/** Constant with value NaN. */
@SuppressWarnings("checkstyle:constantname")
public static final Angle NaN = Angle.ofSi(Double.NaN);
/** Constant with value POSITIVE_INFINITY. */
public static final Angle POSITIVE_INFINITY = Angle.ofSi(Double.POSITIVE_INFINITY);
/** Constant with value NEGATIVE_INFINITY. */
public static final Angle NEGATIVE_INFINITY = Angle.ofSi(Double.NEGATIVE_INFINITY);
/** Constant with value MAX_VALUE. */
public static final Angle POS_MAXVALUE = Angle.ofSi(Double.MAX_VALUE);
/** Constant with value -MAX_VALUE. */
public static final Angle NEG_MAXVALUE = Angle.ofSi(-Double.MAX_VALUE);
/** */
private static final long serialVersionUID = 600L;
/**
* Instantiate a Angle quantity with a unit.
* @param value the value, expressed in the unit
* @param unit the unit in which the value is expressed
*/
public Angle(final double value, final Angle.Unit unit)
{
super(value, unit);
}
/**
* Instantiate a Angle 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 Angle(final double value, final String abbreviation)
{
this(value, Units.resolve(Angle.Unit.class, abbreviation));
}
/**
* Construct Angle quantity.
* @param value Scalar from which to construct this instance
*/
public Angle(final Angle value)
{
super(value.si(), Angle.Unit.SI);
setDisplayUnit(value.getDisplayUnit());
}
/**
* Return a Angle instance based on an SI value.
* @param si the si value
* @return the Angle instance based on an SI value
*/
public static Angle ofSi(final double si)
{
return new Angle(si, Angle.Unit.SI);
}
@Override
public Angle instantiate(final double si)
{
return ofSi(si);
}
@Override
public SIUnit siUnit()
{
return Angle.Unit.SI_UNIT;
}
/**
* Returns a Angle 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 Angle
* @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 Angle valueOf(final String text)
{
return Quantity.valueOf(text, ZERO);
}
/**
* Returns a Angle 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 Angle of(final double value, final String unitString)
{
return Quantity.of(value, unitString, ZERO);
}
/**
* Add an (absolute) direction to this angle, and return a direction. The unit of the return value will be the unit of this
* angle, and the reference of the return value will be the reference belonging to the given direction.
* <code>R.add(A)</code> = unit of R and reference value of A.
* @param direction the absolute direction to add
* @return the absolute direction plus this angle
*/
public final Direction add(final Direction direction)
{
return direction.add(this).setDisplayUnit(getDisplayUnit());
}
/**
* Calculate the division of Angle and Angle, which results in a Dimensionless scalar.
* @param v scalar
* @return scalar as a division of Angle and Angle
*/
public final Dimensionless divide(final Angle v)
{
return new Dimensionless(this.si() / v.si(), Unitless.BASE);
}
/**
* Calculate the multiplication of Angle and Frequency, which results in a AngularVelocity scalar.
* @param v scalar
* @return scalar as a multiplication of Angle and Frequency
*/
public final AngularVelocity multiply(final Frequency v)
{
return new AngularVelocity(this.si() * v.si(), AngularVelocity.Unit.SI);
}
/**
* Calculate the division of Angle and Duration, which results in a AngularVelocity scalar.
* @param v scalar
* @return scalar as a division of Angle and Duration
*/
public final AngularVelocity divide(final Duration v)
{
return new AngularVelocity(this.si() / v.si(), AngularVelocity.Unit.SI);
}
/**
* Calculate the division of Angle and AngularVelocity, which results in a Duration scalar.
* @param v scalar
* @return scalar as a division of Angle and AngularVelocity
*/
public final Duration divide(final AngularVelocity v)
{
return new Duration(this.si() / v.si(), Duration.Unit.SI);
}
/**
* Normalize an angle between 0 and 2 * PI.
* @param angle original angle.
* @return angle between 0 and 2 * PI.
*/
public static double normalize(final double angle)
{
double normalized = angle % (2 * Math.PI);
if (normalized < 0.0)
{
normalized += 2 * Math.PI;
}
return normalized;
}
/**
* Normalize an angle between 0 and 2 * PI.
* @param angle original angle.
* @return a new Angle object with angle between 0 and 2 * PI.
*/
public static Angle normalize(final Angle angle)
{
return new Angle(normalize(angle.si()), Angle.Unit.rad);
}
/******************************************************************************************************/
/********************************************** UNIT CLASS ********************************************/
/******************************************************************************************************/
/**
* Angle.Unit encodes the units of angle (radians, degrees).
* <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<Angle.Unit, Angle>
{
/** The dimensions of Angle: rad. */
public static final SIUnit SI_UNIT = SIUnit.of("rad");
/** radian. */
public static final Angle.Unit rad = new Angle.Unit("rad", "rad", "radian", IdentityScale.SCALE, UnitSystem.SI_DERIVED);
/** The SI or BASE unit. */
public static final Angle.Unit SI = rad;
/** percent (non-linear, 100% is 45 degrees; 90 degrees is infinite). */
public static final Angle.Unit percent = new Angle.Unit("%", "%", "percent", new GradeScale(0.01), UnitSystem.OTHER);
/** degree. */
public static final Angle.Unit deg = rad.deriveUnit("deg", "\u00b0", "degree", Math.PI / 180.0, UnitSystem.SI_ACCEPTED);
/** arcminute. */
public static final Angle.Unit arcmin = deg.deriveUnit("arcmin", "'", "arcminute", 1.0 / 60.0, UnitSystem.OTHER);
/** arcsecond. */
public static final Angle.Unit arcsec = deg.deriveUnit("arcsec", "\"", "arcsecond", 1.0 / 3600.0, UnitSystem.OTHER);
/** grad. */
public static final Angle.Unit grad = rad.deriveUnit("grad", "gradian", 2.0 * Math.PI / 400.0, UnitSystem.OTHER);
/** centesimal arcminute. */
public static final Angle.Unit cdm =
grad.deriveUnit("cdm", "c'", "centesimal arcminute", 1.0 / 100.0, UnitSystem.OTHER);
/** centesimal arcsecond. */
public static final Angle.Unit cds =
grad.deriveUnit("cds", "c\"", "centesimal arcsecond", 1.0 / 10000.0, UnitSystem.OTHER);
/**
* Create a new Angle 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;
}
/** {@inheritDoc} */
@Override
public Angle ofSi(final double si)
{
return Angle.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 Angle.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");
}
}
}