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 * Momentum is the product of an object's mass and velocity, measured in kilogram meters per second (kgm/s).
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 Momentum extends Quantity<Momentum, Momentum.Unit>
22 {
23 /** Constant with value zero. */
24 public static final Momentum ZERO = Momentum.ofSi(0.0);
25
26 /** Constant with value one. */
27 public static final Momentum ONE = Momentum.ofSi(1.0);
28
29 /** Constant with value NaN. */
30 @SuppressWarnings("checkstyle:constantname")
31 public static final Momentum NaN = Momentum.ofSi(Double.NaN);
32
33 /** Constant with value POSITIVE_INFINITY. */
34 public static final Momentum POSITIVE_INFINITY = Momentum.ofSi(Double.POSITIVE_INFINITY);
35
36 /** Constant with value NEGATIVE_INFINITY. */
37 public static final Momentum NEGATIVE_INFINITY = Momentum.ofSi(Double.NEGATIVE_INFINITY);
38
39 /** Constant with value MAX_VALUE. */
40 public static final Momentum POS_MAXVALUE = Momentum.ofSi(Double.MAX_VALUE);
41
42 /** Constant with value -MAX_VALUE. */
43 public static final Momentum NEG_MAXVALUE = Momentum.ofSi(-Double.MAX_VALUE);
44
45 /** */
46 private static final long serialVersionUID = 600L;
47
48 /**
49 * Instantiate a Momentum 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 Momentum(final double value, final Momentum.Unit unit)
54 {
55 super(value, unit);
56 }
57
58 /**
59 * Instantiate a Momentum 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 Momentum(final double value, final String abbreviation)
64 {
65 this(value, Units.resolve(Momentum.Unit.class, abbreviation));
66 }
67
68 /**
69 * Construct Momentum quantity.
70 * @param value Scalar from which to construct this instance
71 */
72 public Momentum(final Momentum value)
73 {
74 super(value.si(), Momentum.Unit.SI);
75 setDisplayUnit(value.getDisplayUnit());
76 }
77
78 /**
79 * Return a Momentum instance based on an SI value.
80 * @param si the si value
81 * @return the Momentum instance based on an SI value
82 */
83 public static Momentum ofSi(final double si)
84 {
85 return new Momentum(si, Momentum.Unit.SI);
86 }
87
88 @Override
89 public Momentum instantiate(final double si)
90 {
91 return ofSi(si);
92 }
93
94 @Override
95 public SIUnit siUnit()
96 {
97 return Momentum.Unit.SI_UNIT;
98 }
99
100 /**
101 * Returns a Momentum representation of a textual representation of a value with a unit. The String representation that can
102 * be parsed is the double value in the unit, followed by a localized or English abbreviation of the unit. Spaces are
103 * allowed, but not required, between the value and the unit.
104 * @param text the textual representation to parse into a Momentum
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 Momentum valueOf(final String text)
110 {
111 return Quantity.valueOf(text, ZERO);
112 }
113
114 /**
115 * Returns a Momentum 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 Momentum of(final double value, final String unitString)
123 {
124 return Quantity.of(value, unitString, ZERO);
125 }
126
127 /**
128 * Calculate the division of Momentum and Momentum, which results in a Dimensionless quantity.
129 * @param v quantity
130 * @return quantity as a division of Momentum and Momentum
131 */
132 public final Dimensionless divide(final Momentum v)
133 {
134 return new Dimensionless(this.si() / v.si(), Unitless.BASE);
135 }
136
137 /**
138 * Calculate the division of Momentum and Speed, which results in a Mass scalar.
139 * @param v scalar
140 * @return scalar as a division of Momentum and Speed
141 */
142 public final Mass divide(final Speed v)
143 {
144 return new Mass(this.si() / v.si(), Mass.Unit.SI);
145 }
146
147 /**
148 * Calculate the division of Momentum and Mass, which results in a Speed scalar.
149 * @param v scalar
150 * @return scalar as a division of Momentum and Mass
151 */
152 public final Speed divide(final Mass v)
153 {
154 return new Speed(this.si() / v.si(), Speed.Unit.SI);
155 }
156
157 /**
158 * Calculate the division of Momentum and Length, which results in a FlowMass scalar.
159 * @param v scalar
160 * @return scalar as a division of Momentum and Length
161 */
162 public final FlowMass divide(final Length v)
163 {
164 return new FlowMass(this.si() / v.si(), FlowMass.Unit.SI);
165 }
166
167 /**
168 * Calculate the division of Momentum and FlowMass, which results in a Length scalar.
169 * @param v scalar
170 * @return scalar as a division of Momentum and FlowMass
171 */
172 public final Length divide(final FlowMass v)
173 {
174 return new Length(this.si() / v.si(), Length.Unit.SI);
175 }
176
177 /**
178 * Calculate the multiplication of Momentum and Speed, which results in a Energy scalar.
179 * @param v scalar
180 * @return scalar as a multiplication of Momentum and Speed
181 */
182 public final Energy multiply(final Speed v)
183 {
184 return new Energy(this.si() * v.si(), Energy.Unit.SI);
185 }
186
187 /**
188 * Calculate the multiplication of Momentum and Acceleration, which results in a Power scalar.
189 * @param v scalar
190 * @return scalar as a multiplication of Momentum and Acceleration
191 */
192 public final Power multiply(final Acceleration v)
193 {
194 return new Power(this.si() * v.si(), Power.Unit.SI);
195 }
196
197 /******************************************************************************************************/
198 /********************************************** UNIT CLASS ********************************************/
199 /******************************************************************************************************/
200
201 /**
202 * Momentum.Unit encodes a unit for the product of an object's mass and velocity.
203 * <p>
204 * Copyright (c) 2025-2026 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved.
205 * See for project information <a href="https://djunits.org" target="_blank">https://djunits.org</a>. The DJUNITS project is
206 * distributed under a <a href="https://djunits.org/docs/license.html" target="_blank">three-clause BSD-style license</a>.
207 * @author Alexander Verbraeck
208 */
209 @SuppressWarnings("checkstyle:constantname")
210 public static class Unit extends AbstractUnit<Momentum.Unit, Momentum>
211 {
212 /** The dimensions of momentum: kgm/s. */
213 public static final SIUnit SI_UNIT = SIUnit.of("kgm/s");
214
215 /** kgm/s. */
216 public static final Momentum.Unit kgm_s =
217 new Momentum.Unit("kgm/s", "kilogram meter per second", 1.0, UnitSystem.SI_DERIVED);
218
219 /** The SI or BASE unit. */
220 public static final Momentum.Unit SI = kgm_s;
221
222 /**
223 * Create a new Momentum unit.
224 * @param id the id or main abbreviation of the unit
225 * @param name the full name of the unit
226 * @param scaleFactorToBaseUnit the scale factor of the unit to convert it TO the base (SI) unit
227 * @param unitSystem the unit system such as SI or IMPERIAL
228 */
229 public Unit(final String id, final String name, final double scaleFactorToBaseUnit, final UnitSystem unitSystem)
230 {
231 super(id, name, new LinearScale(scaleFactorToBaseUnit), unitSystem);
232 }
233
234 /**
235 * Return a derived unit for this unit, with textual abbreviation(s) and a display abbreviation.
236 * @param textualAbbreviation the textual abbreviation of the unit, which doubles as the id
237 * @param displayAbbreviation the display abbreviation of the unit
238 * @param name the full name of the unit
239 * @param scale the scale to use to convert between this unit and the standard (e.g., SI, BASE) unit
240 * @param unitSystem unit system, e.g. SI or Imperial
241 */
242 public Unit(final String textualAbbreviation, final String displayAbbreviation, final String name, final Scale scale,
243 final UnitSystem unitSystem)
244 {
245 super(textualAbbreviation, displayAbbreviation, name, scale, unitSystem);
246 }
247
248 @Override
249 public SIUnit siUnit()
250 {
251 return SI_UNIT;
252 }
253
254 @Override
255 public Unit getBaseUnit()
256 {
257 return SI;
258 }
259
260 @Override
261 public Momentum ofSi(final double si)
262 {
263 return Momentum.ofSi(si);
264 }
265
266 @Override
267 public Unit deriveUnit(final String textualAbbreviation, final String displayAbbreviation, final String name,
268 final double scaleFactor, final UnitSystem unitSystem)
269 {
270 if (getScale() instanceof LinearScale ls)
271 {
272 return new Momentum.Unit(textualAbbreviation, displayAbbreviation, name,
273 new LinearScale(ls.getScaleFactorToBaseUnit() * scaleFactor), unitSystem);
274 }
275 throw new UnitRuntimeException("Only possible to derive a unit from a unit with a linear scale");
276 }
277
278 }
279 }