1 package org.djunits.quantity;
2
3 import org.djunits.quantity.def.Quantity;
4 import org.djunits.unit.AbstractUnit;
5 import org.djunits.unit.UnitInterface;
6 import org.djunits.unit.UnitRuntimeException;
7 import org.djunits.unit.Unitless;
8 import org.djunits.unit.scale.LinearScale;
9 import org.djunits.unit.scale.Scale;
10 import org.djunits.unit.si.SIPrefix;
11 import org.djunits.unit.si.SIUnit;
12 import org.djunits.unit.system.UnitSystem;
13
14 /**
15 * Density is mass per unit volume of a substance, measured in kilograms per cubic meter (kg/m3).
16 * <p>
17 * Copyright (c) 2025-2026 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved. See
18 * for project information <a href="https://djunits.org" target="_blank">https://djunits.org</a>. The DJUNITS project is
19 * distributed under a <a href="https://djunits.org/docs/license.html" target="_blank">three-clause BSD-style license</a>.
20 * @author Alexander Verbraeck
21 */
22 public class Density extends Quantity<Density>
23 {
24 /** Constant with value zero. */
25 public static final Density ZERO = ofSi(0.0);
26
27 /** Constant with value one. */
28 public static final Density ONE = ofSi(1.0);
29
30 /** Constant with value NaN. */
31 @SuppressWarnings("checkstyle:constantname")
32 public static final Density NaN = ofSi(Double.NaN);
33
34 /** Constant with value POSITIVE_INFINITY. */
35 public static final Density POSITIVE_INFINITY = ofSi(Double.POSITIVE_INFINITY);
36
37 /** Constant with value NEGATIVE_INFINITY. */
38 public static final Density NEGATIVE_INFINITY = ofSi(Double.NEGATIVE_INFINITY);
39
40 /** Constant with value MAX_VALUE. */
41 public static final Density POS_MAXVALUE = ofSi(Double.MAX_VALUE);
42
43 /** Constant with value -MAX_VALUE. */
44 public static final Density NEG_MAXVALUE = ofSi(-Double.MAX_VALUE);
45
46 /** */
47 private static final long serialVersionUID = 600L;
48
49 /**
50 * Instantiate a Density quantity with an SI or base value and a display unit.
51 * @param value the quantity value expressed in the SI or base unit
52 * @param displayUnit the display unit to use
53 * @param useSi use SI value when true, use value in unit when false
54 */
55 public Density(final double value, final Density.Unit displayUnit, final boolean useSi)
56 {
57 super(value, displayUnit, useSi);
58 }
59
60 /**
61 * Instantiate a Density quantity expressed in the given unit.
62 * @param valueInUnit the quantity value expressed in the given unit
63 * @param unit the unit of the value, also acts as the display unit
64 */
65 public Density(final double valueInUnit, final Density.Unit unit)
66 {
67 this(valueInUnit, unit, false);
68 }
69
70 /**
71 * Return a Density instance based on an SI value.
72 * @param si the si value
73 * @return the Density instance based on an SI value
74 */
75 public static Density ofSi(final double si)
76 {
77 return new Density(si, Density.Unit.SI, true);
78 }
79
80 /**
81 * Instantiate a Density quantity with an SI or base value and a display unit.
82 * @param siValue the quantity value expressed in the SI or base unit
83 * @param displayUnit the display unit to use
84 * @return the Density instance based on an SI value with the given display unit
85 */
86 public static Density ofSi(final double siValue, final Density.Unit displayUnit)
87 {
88 return new Density(siValue, displayUnit, true);
89 }
90
91 @Override
92 public Density instantiateSi(final double siValue, final UnitInterface<Density> displayUnit)
93 {
94 return new Density(siValue, (Density.Unit) displayUnit, true);
95 }
96
97 /**
98 * Returns a Density representation of a textual representation of a value with a unit. The String representation that can
99 * be parsed is the double value in the unit, followed by a localized or English abbreviation of the unit. Spaces are
100 * allowed, but not required, between the value and the unit.
101 * @param text the textual representation to parse into a Density
102 * @return the Scalar representation of the value in its unit
103 * @throws IllegalArgumentException when the text cannot be parsed
104 * @throws NullPointerException when the text argument is null
105 */
106 public static Density valueOf(final String text)
107 {
108 return Quantity.valueOf(text, ZERO);
109 }
110
111 /**
112 * Returns a Density based on a value expressed in the unit.
113 * @param valueInUnit the value, expressed in the given unit
114 * @param unit the unit of the value, also acts as the display unit
115 * @return ab Density representation of the value in its unit
116 */
117 public static Density of(final double valueInUnit, final Density.Unit unit)
118 {
119 return new Density(valueInUnit, unit);
120 }
121
122 /**
123 * Returns a Density based on a value and the textual representation of the unit, which can be localized.
124 * @param valueInUnit the value, expressed in the unit as given by unitString
125 * @param unitString the textual representation of the unit
126 * @return the Scalar representation of the value in its unit
127 * @throws IllegalArgumentException when the unit cannot be parsed or is incorrect
128 * @throws NullPointerException when the unitString argument is null
129 */
130 public static Density of(final double valueInUnit, final String unitString)
131 {
132 return Quantity.of(valueInUnit, unitString, ZERO);
133 }
134
135 @Override
136 public Density.Unit getDisplayUnit()
137 {
138 return (Density.Unit) super.getDisplayUnit();
139 }
140
141 /**
142 * Calculate the division of Density and Density, which results in a Dimensionless quantity.
143 * @param v quantity
144 * @return quantity as a division of Density and Density
145 */
146 public Dimensionless divide(final Density v)
147 {
148 return new Dimensionless(this.si() / v.si(), Unitless.BASE);
149 }
150
151 /**
152 * Calculate the multiplication of Density and Volume, which results in a Mass scalar.
153 * @param v scalar
154 * @return scalar as a multiplication of Density and Volume
155 */
156 public Mass multiply(final Volume v)
157 {
158 return new Mass(this.si() * v.si(), Mass.Unit.SI);
159 }
160
161 /**
162 * Calculate the multiplication of Density and FlowVolume, which results in a FlowMass scalar.
163 * @param v scalar
164 * @return scalar as a multiplication of Density and FlowVolume
165 */
166 public FlowMass multiply(final FlowVolume v)
167 {
168 return new FlowMass(this.si() * v.si(), FlowMass.Unit.SI);
169 }
170
171 /******************************************************************************************************/
172 /********************************************** UNIT CLASS ********************************************/
173 /******************************************************************************************************/
174
175 /**
176 * Density.Unit encodes the units of density based on mass per volume.
177 * <p>
178 * Copyright (c) 2025-2026 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved.
179 * See for project information <a href="https://djunits.org" target="_blank">https://djunits.org</a>. The DJUNITS project is
180 * distributed under a <a href="https://djunits.org/docs/license.html" target="_blank">three-clause BSD-style license</a>.
181 * @author Alexander Verbraeck
182 */
183 @SuppressWarnings("checkstyle:constantname")
184 public static class Unit extends AbstractUnit<Density>
185 {
186 /** The dimensions of the absorbed dose: kg/m3. */
187 public static final SIUnit SI_UNIT = SIUnit.of("kg/m3");
188
189 /** kg/m^3. */
190 public static final Density.Unit kg_m3 =
191 new Density.Unit("kg/m3", "kilogram per cubic meter", 1.0, UnitSystem.SI_DERIVED);
192
193 /** The SI or BASE unit. */
194 public static final Density.Unit SI = kg_m3;
195
196 /** g/cm^3. */
197 public static final Density.Unit g_cm3 =
198 kg_m3.deriveUnit("g/cm3", "gram per cubic centimeter", 1.0E3, UnitSystem.SI_DERIVED);
199
200 /**
201 * Create a new Density unit.
202 * @param id the id or main abbreviation of the unit
203 * @param name the full name of the unit
204 * @param scaleFactorToBaseUnit the scale factor of the unit to convert it TO the base (SI) unit
205 * @param unitSystem the unit system such as SI or IMPERIAL
206 */
207 public Unit(final String id, final String name, final double scaleFactorToBaseUnit, final UnitSystem unitSystem)
208 {
209 super(id, name, scaleFactorToBaseUnit, unitSystem);
210 }
211
212 /**
213 * Return a derived unit for this unit, with textual abbreviation(s) and a display abbreviation.
214 * @param textualAbbreviation the textual abbreviation of the unit, which doubles as the id
215 * @param displayAbbreviation the display abbreviation of the unit
216 * @param name the full name of the unit
217 * @param scale the scale to use to convert from this unit to the standard (e.g., SI, BASE) unit
218 * @param unitSystem unit system, e.g. SI or Imperial
219 * @param siPrefix the SI Prefix of this unit
220 */
221 public Unit(final String textualAbbreviation, final String displayAbbreviation, final String name, final Scale scale,
222 final UnitSystem unitSystem, final SIPrefix siPrefix)
223 {
224 super(textualAbbreviation, displayAbbreviation, name, scale, unitSystem, siPrefix);
225 }
226
227 @Override
228 public SIUnit siUnit()
229 {
230 return SI_UNIT;
231 }
232
233 @Override
234 public Unit getBaseUnit()
235 {
236 return SI;
237 }
238
239 @Override
240 public Density ofSi(final double si, final UnitInterface<Density> displayUnit)
241 {
242 return new Density(si, (Unit) displayUnit, true);
243 }
244
245 @Override
246 public Density.Unit deriveUnit(final String textualAbbreviation, final String displayAbbreviation, final String name,
247 final double scaleFactor, final UnitSystem unitSystem, final SIPrefix siPrefix)
248 {
249 if (getScale() instanceof LinearScale ls)
250 {
251 return new Density.Unit(textualAbbreviation, displayAbbreviation, name,
252 new LinearScale(ls.getScaleFactorToBaseUnit() * scaleFactor), unitSystem, siPrefix);
253 }
254 throw new UnitRuntimeException("Only possible to derive a unit from a unit with a linear scale");
255 }
256
257 @Override
258 public Density.Unit deriveUnit(final String abbreviation, final String name, final double scaleFactor,
259 final UnitSystem unitSystem)
260 {
261 return (Unit) super.deriveUnit(abbreviation, name, scaleFactor, unitSystem);
262 }
263
264 }
265
266 }