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.scale.LinearScale;
8 import org.djunits.unit.scale.Scale;
9 import org.djunits.unit.si.SIUnit;
10 import org.djunits.unit.system.UnitSystem;
11
12 /**
13 * Density is mass per unit volume of a substance, measured in kilograms per cubic meter (kg/m3).
14 * <p>
15 * Copyright (c) 2025-2026 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved. See
16 * for project information <a href="https://djunits.org" target="_blank">https://djunits.org</a>. The DJUNITS project is
17 * distributed under a <a href="https://djunits.org/docs/license.html" target="_blank">three-clause BSD-style license</a>.
18 * @author Alexander Verbraeck
19 */
20 public class Density extends Quantity<Density>
21 {
22 /** Constant with value zero. */
23 public static final Density ZERO = ofSi(0.0);
24
25 /** Constant with value one. */
26 public static final Density ONE = ofSi(1.0);
27
28 /** Constant with value NaN. */
29 @SuppressWarnings("checkstyle:constantname")
30 public static final Density NaN = ofSi(Double.NaN);
31
32 /** Constant with value POSITIVE_INFINITY. */
33 public static final Density POSITIVE_INFINITY = ofSi(Double.POSITIVE_INFINITY);
34
35 /** Constant with value NEGATIVE_INFINITY. */
36 public static final Density NEGATIVE_INFINITY = ofSi(Double.NEGATIVE_INFINITY);
37
38 /** Constant with value MAX_VALUE. */
39 public static final Density POS_MAXVALUE = ofSi(Double.MAX_VALUE);
40
41 /** Constant with value -MAX_VALUE. */
42 public static final Density NEG_MAXVALUE = ofSi(-Double.MAX_VALUE);
43
44 /** */
45 private static final long serialVersionUID = 600L;
46
47 /**
48 * Instantiate a Density quantity with a unit.
49 * @param valueInUnit the value, expressed in the unit
50 * @param unit the unit in which the value is expressed
51 */
52 public Density(final double valueInUnit, final Density.Unit unit)
53 {
54 super(valueInUnit, unit);
55 }
56
57 /**
58 * Return a Density instance based on an SI value.
59 * @param si the si value
60 * @return the Density instance based on an SI value
61 */
62 public static Density ofSi(final double si)
63 {
64 return new Density(si, Density.Unit.SI);
65 }
66
67 @Override
68 public Density instantiateSi(final double si)
69 {
70 return ofSi(si);
71 }
72
73 @Override
74 public SIUnit siUnit()
75 {
76 return Density.Unit.SI_UNIT;
77 }
78
79 /**
80 * Returns a Density representation of a textual representation of a value with a unit. The String representation that can
81 * be parsed is the double value in the unit, followed by a localized or English abbreviation of the unit. Spaces are
82 * allowed, but not required, between the value and the unit.
83 * @param text the textual representation to parse into a Density
84 * @return the Scalar representation of the value in its unit
85 * @throws IllegalArgumentException when the text cannot be parsed
86 * @throws NullPointerException when the text argument is null
87 */
88 public static Density valueOf(final String text)
89 {
90 return Quantity.valueOf(text, ZERO);
91 }
92
93 /**
94 * Returns a Density based on a value and the textual representation of the unit, which can be localized.
95 * @param valueInUnit the value, expressed in the unit as given by unitString
96 * @param unitString the textual representation of the unit
97 * @return the Scalar representation of the value in its unit
98 * @throws IllegalArgumentException when the unit cannot be parsed or is incorrect
99 * @throws NullPointerException when the unitString argument is null
100 */
101 public static Density of(final double valueInUnit, final String unitString)
102 {
103 return Quantity.of(valueInUnit, unitString, ZERO);
104 }
105
106 @Override
107 public Density.Unit getDisplayUnit()
108 {
109 return (Density.Unit) super.getDisplayUnit();
110 }
111
112 /**
113 * Calculate the division of Density and Density, which results in a Dimensionless quantity.
114 * @param v quantity
115 * @return quantity as a division of Density and Density
116 */
117 public final Dimensionless divide(final Density v)
118 {
119 return new Dimensionless(this.si() / v.si(), Unitless.BASE);
120 }
121
122 /**
123 * Calculate the multiplication of Density and Volume, which results in a Mass scalar.
124 * @param v scalar
125 * @return scalar as a multiplication of Density and Volume
126 */
127 public final Mass multiply(final Volume v)
128 {
129 return new Mass(this.si() * v.si(), Mass.Unit.SI);
130 }
131
132 /**
133 * Calculate the multiplication of Density and FlowVolume, which results in a FlowMass scalar.
134 * @param v scalar
135 * @return scalar as a multiplication of Density and FlowVolume
136 */
137 public final FlowMass multiply(final FlowVolume v)
138 {
139 return new FlowMass(this.si() * v.si(), FlowMass.Unit.SI);
140 }
141
142 /******************************************************************************************************/
143 /********************************************** UNIT CLASS ********************************************/
144 /******************************************************************************************************/
145
146 /**
147 * Density.Unit encodes the units of density based on mass per volume.
148 * <p>
149 * Copyright (c) 2025-2026 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved.
150 * See for project information <a href="https://djunits.org" target="_blank">https://djunits.org</a>. The DJUNITS project is
151 * distributed under a <a href="https://djunits.org/docs/license.html" target="_blank">three-clause BSD-style license</a>.
152 * @author Alexander Verbraeck
153 */
154 @SuppressWarnings("checkstyle:constantname")
155 public static class Unit extends AbstractUnit<Density.Unit, Density>
156 {
157 /** The dimensions of the absorbed dose: kg/m3. */
158 public static final SIUnit SI_UNIT = SIUnit.of("kg/m3");
159
160 /** kg/m^3. */
161 public static final Density.Unit kg_m3 =
162 new Density.Unit("kg/m3", "kilogram per cubic meter", 1.0, UnitSystem.SI_DERIVED);
163
164 /** The SI or BASE unit. */
165 public static final Density.Unit SI = kg_m3;
166
167 /** g/cm^3. */
168 public static final Density.Unit g_cm3 =
169 kg_m3.deriveUnit("g/cm3", "gram per cubic centimeter", 1.0E3, UnitSystem.SI_DERIVED);
170
171 /**
172 * Create a new Density 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 Density ofSi(final double si)
211 {
212 return Density.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 Density.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 }