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 * Momentum is the product of an object's mass and velocity, measured in kilogram meters per second (kgm/s).
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 Momentum extends Quantity<Momentum>
21 {
22 /** Constant with value zero. */
23 public static final Momentum ZERO = ofSi(0.0);
24
25 /** Constant with value one. */
26 public static final Momentum ONE = ofSi(1.0);
27
28 /** Constant with value NaN. */
29 @SuppressWarnings("checkstyle:constantname")
30 public static final Momentum NaN = ofSi(Double.NaN);
31
32 /** Constant with value POSITIVE_INFINITY. */
33 public static final Momentum POSITIVE_INFINITY = ofSi(Double.POSITIVE_INFINITY);
34
35 /** Constant with value NEGATIVE_INFINITY. */
36 public static final Momentum NEGATIVE_INFINITY = ofSi(Double.NEGATIVE_INFINITY);
37
38 /** Constant with value MAX_VALUE. */
39 public static final Momentum POS_MAXVALUE = ofSi(Double.MAX_VALUE);
40
41 /** Constant with value -MAX_VALUE. */
42 public static final Momentum NEG_MAXVALUE = ofSi(-Double.MAX_VALUE);
43
44 /** */
45 private static final long serialVersionUID = 600L;
46
47 /**
48 * Instantiate a Momentum 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 Momentum(final double valueInUnit, final Momentum.Unit unit)
53 {
54 super(valueInUnit, unit);
55 }
56
57 /**
58 * Return a Momentum instance based on an SI value.
59 * @param si the si value
60 * @return the Momentum instance based on an SI value
61 */
62 public static Momentum ofSi(final double si)
63 {
64 return new Momentum(si, Momentum.Unit.SI);
65 }
66
67 @Override
68 public Momentum instantiateSi(final double si)
69 {
70 return ofSi(si);
71 }
72
73 @Override
74 public SIUnit siUnit()
75 {
76 return Momentum.Unit.SI_UNIT;
77 }
78
79 /**
80 * Returns a Momentum 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 Momentum
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 Momentum valueOf(final String text)
89 {
90 return Quantity.valueOf(text, ZERO);
91 }
92
93 /**
94 * Returns a Momentum 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 Momentum of(final double valueInUnit, final String unitString)
102 {
103 return Quantity.of(valueInUnit, unitString, ZERO);
104 }
105
106 @Override
107 public Momentum.Unit getDisplayUnit()
108 {
109 return (Momentum.Unit) super.getDisplayUnit();
110 }
111
112 /**
113 * Calculate the division of Momentum and Momentum, which results in a Dimensionless quantity.
114 * @param v quantity
115 * @return quantity as a division of Momentum and Momentum
116 */
117 public final Dimensionless divide(final Momentum v)
118 {
119 return new Dimensionless(this.si() / v.si(), Unitless.BASE);
120 }
121
122 /**
123 * Calculate the division of Momentum and Speed, which results in a Mass scalar.
124 * @param v scalar
125 * @return scalar as a division of Momentum and Speed
126 */
127 public final Mass divide(final Speed v)
128 {
129 return new Mass(this.si() / v.si(), Mass.Unit.SI);
130 }
131
132 /**
133 * Calculate the division of Momentum and Mass, which results in a Speed scalar.
134 * @param v scalar
135 * @return scalar as a division of Momentum and Mass
136 */
137 public final Speed divide(final Mass v)
138 {
139 return new Speed(this.si() / v.si(), Speed.Unit.SI);
140 }
141
142 /**
143 * Calculate the division of Momentum and Length, which results in a FlowMass scalar.
144 * @param v scalar
145 * @return scalar as a division of Momentum and Length
146 */
147 public final FlowMass divide(final Length v)
148 {
149 return new FlowMass(this.si() / v.si(), FlowMass.Unit.SI);
150 }
151
152 /**
153 * Calculate the division of Momentum and FlowMass, which results in a Length scalar.
154 * @param v scalar
155 * @return scalar as a division of Momentum and FlowMass
156 */
157 public final Length divide(final FlowMass v)
158 {
159 return new Length(this.si() / v.si(), Length.Unit.SI);
160 }
161
162 /**
163 * Calculate the multiplication of Momentum and Speed, which results in a Energy scalar.
164 * @param v scalar
165 * @return scalar as a multiplication of Momentum and Speed
166 */
167 public final Energy multiply(final Speed v)
168 {
169 return new Energy(this.si() * v.si(), Energy.Unit.SI);
170 }
171
172 /**
173 * Calculate the multiplication of Momentum and Acceleration, which results in a Power scalar.
174 * @param v scalar
175 * @return scalar as a multiplication of Momentum and Acceleration
176 */
177 public final Power multiply(final Acceleration v)
178 {
179 return new Power(this.si() * v.si(), Power.Unit.SI);
180 }
181
182 /******************************************************************************************************/
183 /********************************************** UNIT CLASS ********************************************/
184 /******************************************************************************************************/
185
186 /**
187 * Momentum.Unit encodes a unit for the product of an object's mass and velocity.
188 * <p>
189 * Copyright (c) 2025-2026 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved.
190 * See for project information <a href="https://djunits.org" target="_blank">https://djunits.org</a>. The DJUNITS project is
191 * distributed under a <a href="https://djunits.org/docs/license.html" target="_blank">three-clause BSD-style license</a>.
192 * @author Alexander Verbraeck
193 */
194 @SuppressWarnings("checkstyle:constantname")
195 public static class Unit extends AbstractUnit<Momentum.Unit, Momentum>
196 {
197 /** The dimensions of momentum: kgm/s. */
198 public static final SIUnit SI_UNIT = SIUnit.of("kgm/s");
199
200 /** kgm/s. */
201 public static final Momentum.Unit kgm_s =
202 new Momentum.Unit("kgm/s", "kilogram meter per second", 1.0, UnitSystem.SI_DERIVED);
203
204 /** The SI or BASE unit. */
205 public static final Momentum.Unit SI = kgm_s;
206
207 /**
208 * Create a new Momentum unit.
209 * @param id the id or main abbreviation of the unit
210 * @param name the full name of the unit
211 * @param scaleFactorToBaseUnit the scale factor of the unit to convert it TO the base (SI) unit
212 * @param unitSystem the unit system such as SI or IMPERIAL
213 */
214 public Unit(final String id, final String name, final double scaleFactorToBaseUnit, final UnitSystem unitSystem)
215 {
216 super(id, name, new LinearScale(scaleFactorToBaseUnit), unitSystem);
217 }
218
219 /**
220 * Return a derived unit for this unit, with textual abbreviation(s) and a display abbreviation.
221 * @param textualAbbreviation the textual abbreviation of the unit, which doubles as the id
222 * @param displayAbbreviation the display abbreviation of the unit
223 * @param name the full name of the unit
224 * @param scale the scale to use to convert between this unit and the standard (e.g., SI, BASE) unit
225 * @param unitSystem unit system, e.g. SI or Imperial
226 */
227 public Unit(final String textualAbbreviation, final String displayAbbreviation, final String name, final Scale scale,
228 final UnitSystem unitSystem)
229 {
230 super(textualAbbreviation, displayAbbreviation, name, scale, unitSystem);
231 }
232
233 @Override
234 public SIUnit siUnit()
235 {
236 return SI_UNIT;
237 }
238
239 @Override
240 public Unit getBaseUnit()
241 {
242 return SI;
243 }
244
245 @Override
246 public Momentum ofSi(final double si)
247 {
248 return Momentum.ofSi(si);
249 }
250
251 @Override
252 public Unit deriveUnit(final String textualAbbreviation, final String displayAbbreviation, final String name,
253 final double scaleFactor, final UnitSystem unitSystem)
254 {
255 if (getScale() instanceof LinearScale ls)
256 {
257 return new Momentum.Unit(textualAbbreviation, displayAbbreviation, name,
258 new LinearScale(ls.getScaleFactorToBaseUnit() * scaleFactor), unitSystem);
259 }
260 throw new UnitRuntimeException("Only possible to derive a unit from a unit with a linear scale");
261 }
262
263 }
264 }