1 package org.djunits.quantity;
2
3 import org.djunits.quantity.def.Quantity;
4 import org.djunits.unit.AbstractUnit;
5 import org.djunits.unit.UnitRuntimeException;
6 import org.djunits.unit.Unitless;
7 import org.djunits.unit.Units;
8 import org.djunits.unit.scale.LinearScale;
9 import org.djunits.unit.scale.Scale;
10 import org.djunits.unit.si.SIUnit;
11 import org.djunits.unit.system.UnitSystem;
12
13 /**
14 * Luminous intensity is the luminous flux emitted per unit solid angle, measured in candelas (cd).
15 * <p>
16 * Copyright (c) 2025-2026 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved. See
17 * for project information <a href="https://djunits.org" target="_blank">https://djunits.org</a>. The DJUNITS project is
18 * distributed under a <a href="https://djunits.org/docs/license.html" target="_blank">three-clause BSD-style license</a>.
19 * @author Alexander Verbraeck
20 */
21 public class LuminousIntensity extends Quantity<LuminousIntensity, LuminousIntensity.Unit>
22 {
23 /** Constant with value zero. */
24 public static final LuminousIntensity ZERO = LuminousIntensity.ofSi(0.0);
25
26 /** Constant with value one. */
27 public static final LuminousIntensity ONE = LuminousIntensity.ofSi(1.0);
28
29 /** Constant with value NaN. */
30 @SuppressWarnings("checkstyle:constantname")
31 public static final LuminousIntensity NaN = LuminousIntensity.ofSi(Double.NaN);
32
33 /** Constant with value POSITIVE_INFINITY. */
34 public static final LuminousIntensity POSITIVE_INFINITY = LuminousIntensity.ofSi(Double.POSITIVE_INFINITY);
35
36 /** Constant with value NEGATIVE_INFINITY. */
37 public static final LuminousIntensity NEGATIVE_INFINITY = LuminousIntensity.ofSi(Double.NEGATIVE_INFINITY);
38
39 /** Constant with value MAX_VALUE. */
40 public static final LuminousIntensity POS_MAXVALUE = LuminousIntensity.ofSi(Double.MAX_VALUE);
41
42 /** Constant with value -MAX_VALUE. */
43 public static final LuminousIntensity NEG_MAXVALUE = LuminousIntensity.ofSi(-Double.MAX_VALUE);
44
45 /** */
46 private static final long serialVersionUID = 600L;
47
48 /**
49 * Instantiate a LuminousIntensity quantity with a unit.
50 * @param value the value, expressed in the unit
51 * @param unit the unit in which the value is expressed
52 */
53 public LuminousIntensity(final double value, final LuminousIntensity.Unit unit)
54 {
55 super(value, unit);
56 }
57
58 /**
59 * Instantiate a LuminousIntensity quantity with a unit, expressed as a String.
60 * @param value the value, expressed in the unit
61 * @param abbreviation the String abbreviation of the unit in which the value is expressed
62 */
63 public LuminousIntensity(final double value, final String abbreviation)
64 {
65 this(value, Units.resolve(LuminousIntensity.Unit.class, abbreviation));
66 }
67
68 /**
69 * Construct LuminousIntensity quantity.
70 * @param value Scalar from which to construct this instance
71 */
72 public LuminousIntensity(final LuminousIntensity value)
73 {
74 super(value.si(), LuminousIntensity.Unit.SI);
75 setDisplayUnit(value.getDisplayUnit());
76 }
77
78 /**
79 * Return a LuminousIntensity instance based on an SI value.
80 * @param si the si value
81 * @return the LuminousIntensity instance based on an SI value
82 */
83 public static LuminousIntensity ofSi(final double si)
84 {
85 return new LuminousIntensity(si, LuminousIntensity.Unit.SI);
86 }
87
88 @Override
89 public LuminousIntensity instantiate(final double si)
90 {
91 return ofSi(si);
92 }
93
94 @Override
95 public SIUnit siUnit()
96 {
97 return LuminousIntensity.Unit.SI_UNIT;
98 }
99
100 /**
101 * Returns a LuminousIntensity representation of a textual representation of a value with a unit. The String representation
102 * that can be parsed is the double value in the unit, followed by a localized or English abbreviation of the unit. Spaces
103 * are allowed, but not required, between the value and the unit.
104 * @param text the textual representation to parse into a LuminousIntensity
105 * @return the Scalar representation of the value in its unit
106 * @throws IllegalArgumentException when the text cannot be parsed
107 * @throws NullPointerException when the text argument is null
108 */
109 public static LuminousIntensity valueOf(final String text)
110 {
111 return Quantity.valueOf(text, ZERO);
112 }
113
114 /**
115 * Returns a LuminousIntensity based on a value and the textual representation of the unit, which can be localized.
116 * @param value the value to use
117 * @param unitString the textual representation of the unit
118 * @return the Scalar representation of the value in its unit
119 * @throws IllegalArgumentException when the unit cannot be parsed or is incorrect
120 * @throws NullPointerException when the unitString argument is null
121 */
122 public static LuminousIntensity of(final double value, final String unitString)
123 {
124 return Quantity.of(value, unitString, ZERO);
125 }
126
127 /**
128 * Calculate the division of LuminousIntensity and LuminousIntensity, which results in a Dimensionless quantity.
129 * @param v quantity
130 * @return quantity as a division of LuminousIntensity and LuminousIntensity
131 */
132 public final Dimensionless divide(final LuminousIntensity v)
133 {
134 return new Dimensionless(this.si() / v.si(), Unitless.BASE);
135 }
136
137 /**
138 * Calculate the multiplication of LuminousIntensity and SolidAngle, which results in a LuminousFlux scalar.
139 * @param v scalar
140 * @return scalar as a multiplication of LuminousIntensity and SolidAngle
141 */
142 public final LuminousFlux multiply(final SolidAngle v)
143 {
144 return new LuminousFlux(this.si() * v.si(), LuminousFlux.Unit.SI);
145 }
146
147 /******************************************************************************************************/
148 /********************************************** UNIT CLASS ********************************************/
149 /******************************************************************************************************/
150
151 /**
152 * LuminousIntensity.Unit encodes the units of luminous flux emitted per unit solid angle.
153 * <p>
154 * Copyright (c) 2025-2026 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved.
155 * See for project information <a href="https://djunits.org" target="_blank">https://djunits.org</a>. The DJUNITS project is
156 * distributed under a <a href="https://djunits.org/docs/license.html" target="_blank">three-clause BSD-style license</a>.
157 * @author Alexander Verbraeck
158 */
159 @SuppressWarnings("checkstyle:constantname")
160 public static class Unit extends AbstractUnit<LuminousIntensity.Unit, LuminousIntensity>
161 {
162 /** The dimensions of the luminous flux emitted per unit solid angle: cd. */
163 public static final SIUnit SI_UNIT = SIUnit.of("cd");
164
165 /** Candela. */
166 public static final LuminousIntensity.Unit cd = new LuminousIntensity.Unit("cd", "candela", 1.0, UnitSystem.SI_DERIVED);
167
168 /** The SI or BASE unit. */
169 public static final LuminousIntensity.Unit SI = cd.generateSiPrefixes(false, false);
170
171 /**
172 * Create a new LuminousIntensity unit.
173 * @param id the id or main abbreviation of the unit
174 * @param name the full name of the unit
175 * @param scaleFactorToBaseUnit the scale factor of the unit to convert it TO the base (SI) unit
176 * @param unitSystem the unit system such as SI or IMPERIAL
177 */
178 public Unit(final String id, final String name, final double scaleFactorToBaseUnit, final UnitSystem unitSystem)
179 {
180 super(id, name, new LinearScale(scaleFactorToBaseUnit), unitSystem);
181 }
182
183 /**
184 * Return a derived unit for this unit, with textual abbreviation(s) and a display abbreviation.
185 * @param textualAbbreviation the textual abbreviation of the unit, which doubles as the id
186 * @param displayAbbreviation the display abbreviation of the unit
187 * @param name the full name of the unit
188 * @param scale the scale to use to convert between this unit and the standard (e.g., SI, BASE) unit
189 * @param unitSystem unit system, e.g. SI or Imperial
190 */
191 public Unit(final String textualAbbreviation, final String displayAbbreviation, final String name, final Scale scale,
192 final UnitSystem unitSystem)
193 {
194 super(textualAbbreviation, displayAbbreviation, name, scale, unitSystem);
195 }
196
197 @Override
198 public SIUnit siUnit()
199 {
200 return SI_UNIT;
201 }
202
203 @Override
204 public Unit getBaseUnit()
205 {
206 return SI;
207 }
208
209 @Override
210 public LuminousIntensity ofSi(final double si)
211 {
212 return LuminousIntensity.ofSi(si);
213 }
214
215 @Override
216 public Unit deriveUnit(final String textualAbbreviation, final String displayAbbreviation, final String name,
217 final double scaleFactor, final UnitSystem unitSystem)
218 {
219 if (getScale() instanceof LinearScale ls)
220 {
221 return new LuminousIntensity.Unit(textualAbbreviation, displayAbbreviation, name,
222 new LinearScale(ls.getScaleFactorToBaseUnit() * scaleFactor), unitSystem);
223 }
224 throw new UnitRuntimeException("Only possible to derive a unit from a unit with a linear scale");
225 }
226
227 }
228 }