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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   * Energy is a physical quantity representing the capacity to do work, measured in joules (J).
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 Energy extends Quantity<Energy>
22  {
23      /** Constant with value zero. */
24      public static final Energy ZERO = Energy.ofSi(0.0);
25  
26      /** Constant with value one. */
27      public static final Energy ONE = Energy.ofSi(1.0);
28  
29      /** Constant with value NaN. */
30      @SuppressWarnings("checkstyle:constantname")
31      public static final Energy NaN = Energy.ofSi(Double.NaN);
32  
33      /** Constant with value POSITIVE_INFINITY. */
34      public static final Energy POSITIVE_INFINITY = Energy.ofSi(Double.POSITIVE_INFINITY);
35  
36      /** Constant with value NEGATIVE_INFINITY. */
37      public static final Energy NEGATIVE_INFINITY = Energy.ofSi(Double.NEGATIVE_INFINITY);
38  
39      /** Constant with value MAX_VALUE. */
40      public static final Energy POS_MAXVALUE = Energy.ofSi(Double.MAX_VALUE);
41  
42      /** Constant with value -MAX_VALUE. */
43      public static final Energy NEG_MAXVALUE = Energy.ofSi(-Double.MAX_VALUE);
44  
45      /** */
46      private static final long serialVersionUID = 600L;
47  
48      /**
49       * Instantiate a Energy quantity with a unit.
50       * @param valueInUnit the value, expressed in the unit
51       * @param unit the unit in which the value is expressed
52       */
53      public Energy(final double valueInUnit, final Energy.Unit unit)
54      {
55          super(valueInUnit, unit);
56      }
57  
58      /**
59       * Instantiate a Energy quantity with a unit, expressed as a String.
60       * @param valueInUnit the value, expressed in the unit
61       * @param abbreviation the String abbreviation of the unit in which the value is expressed
62       */
63      public Energy(final double valueInUnit, final String abbreviation)
64      {
65          this(valueInUnit, Units.resolve(Energy.Unit.class, abbreviation));
66      }
67  
68      /**
69       * Construct Energy quantity.
70       * @param value Scalar from which to construct this instance
71       */
72      public Energy(final Energy value)
73      {
74          super(value.si(), Energy.Unit.SI);
75          setDisplayUnit(value.getDisplayUnit());
76      }
77  
78      /**
79       * Return a Energy instance based on an SI value.
80       * @param si the si value
81       * @return the Energy instance based on an SI value
82       */
83      public static Energy ofSi(final double si)
84      {
85          return new Energy(si, Energy.Unit.SI);
86      }
87  
88      @Override
89      public Energy instantiateSi(final double si)
90      {
91          return ofSi(si);
92      }
93  
94      @Override
95      public SIUnit siUnit()
96      {
97          return Energy.Unit.SI_UNIT;
98      }
99  
100     /**
101      * Returns a Energy representation of a textual representation of a value with a unit. The String representation that can be
102      * parsed is the double value in the unit, followed by a localized or English abbreviation of the unit. Spaces are allowed,
103      * but not required, between the value and the unit.
104      * @param text the textual representation to parse into a Energy
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 Energy valueOf(final String text)
110     {
111         return Quantity.valueOf(text, ZERO);
112     }
113 
114     /**
115      * Returns a Energy based on a value and the textual representation of the unit, which can be localized.
116      * @param valueInUnit the value, expressed in the unit as given by unitString
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 Energy of(final double valueInUnit, final String unitString)
123     {
124         return Quantity.of(valueInUnit, unitString, ZERO);
125     }
126 
127     @Override
128     public Energy.Unit getDisplayUnit()
129     {
130         return (Energy.Unit) super.getDisplayUnit();
131     }
132 
133     /**
134      * Calculate the division of Energy and Energy, which results in a Dimensionless quantity.
135      * @param v quantity
136      * @return quantity as a division of Energy and Energy
137      */
138     public final Dimensionless divide(final Energy v)
139     {
140         return new Dimensionless(this.si() / v.si(), Unitless.BASE);
141     }
142 
143     /**
144      * Calculate the division of Energy and Force, which results in a Length scalar.
145      * @param v scalar
146      * @return scalar as a division of Energy and Force
147      */
148     public final Length divide(final Force v)
149     {
150         return new Length(this.si() / v.si(), Length.Unit.SI);
151     }
152 
153     /**
154      * Calculate the division of Energy and Length, which results in a Force scalar.
155      * @param v scalar
156      * @return scalar as a division of Energy and Length
157      */
158     public final Force divide(final Length v)
159     {
160         return new Force(this.si() / v.si(), Force.Unit.SI);
161     }
162 
163     /**
164      * Calculate the multiplication of Energy and LinearDensity, which results in a Force scalar.
165      * @param v scalar
166      * @return scalar as a multiplication of Energy and LinearDensity
167      */
168     public final Force multiply(final LinearObjectDensity v)
169     {
170         return new Force(this.si() * v.si(), Force.Unit.SI);
171     }
172 
173     /**
174      * Calculate the division of Energy and Duration, which results in a Power scalar.
175      * @param v scalar
176      * @return scalar as a division of Energy and Duration
177      */
178     public final Power divide(final Duration v)
179     {
180         return new Power(this.si() / v.si(), Power.Unit.SI);
181     }
182 
183     /**
184      * Calculate the division of Energy and Power, which results in a Duration scalar.
185      * @param v scalar
186      * @return scalar as a division of Energy and Power
187      */
188     public final Duration divide(final Power v)
189     {
190         return new Duration(this.si() / v.si(), Duration.Unit.SI);
191     }
192 
193     /**
194      * Calculate the division of Energy and Volume, which results in a Pressure scalar.
195      * @param v scalar
196      * @return scalar as a division of Energy and Volume
197      */
198     public final Pressure divide(final Volume v)
199     {
200         return new Pressure(this.si() / v.si(), Pressure.Unit.SI);
201     }
202 
203     /**
204      * Calculate the division of Energy and Pressure, which results in a Volume scalar.
205      * @param v scalar
206      * @return scalar as a division of Energy and Pressure
207      */
208     public final Volume divide(final Pressure v)
209     {
210         return new Volume(this.si() / v.si(), Volume.Unit.SI);
211     }
212 
213     /**
214      * Calculate the multiplication of Energy and Frequency, which results in a Power scalar.
215      * @param v scalar
216      * @return scalar as a multiplication of Energy and Frequency
217      */
218     public final Power multiply(final Frequency v)
219     {
220         return new Power(this.si() * v.si(), Power.Unit.SI);
221     }
222 
223     /**
224      * Calculate the division of Energy and Speed, which results in a Momentum scalar.
225      * @param v scalar
226      * @return scalar as a division of Energy and Speed
227      */
228     public final Momentum divide(final Speed v)
229     {
230         return new Momentum(this.si() / v.si(), Momentum.Unit.SI);
231     }
232 
233     /**
234      * Calculate the division of Energy and Momentum, which results in a Speed scalar.
235      * @param v scalar
236      * @return scalar as a division of Energy and Momentum
237      */
238     public final Speed divide(final Momentum v)
239     {
240         return new Speed(this.si() / v.si(), Speed.Unit.SI);
241     }
242 
243     /******************************************************************************************************/
244     /********************************************** UNIT CLASS ********************************************/
245     /******************************************************************************************************/
246 
247     /**
248      * Energy.Unit encodes the units of energy.
249      * <p>
250      * Copyright (c) 2025-2026 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved.
251      * See for project information <a href="https://djunits.org" target="_blank">https://djunits.org</a>. The DJUNITS project is
252      * distributed under a <a href="https://djunits.org/docs/license.html" target="_blank">three-clause BSD-style license</a>.
253      * @author Alexander Verbraeck
254      */
255     @SuppressWarnings("checkstyle:constantname")
256     public static class Unit extends AbstractUnit<Energy.Unit, Energy>
257     {
258         /** The dimensions of energy: kgm2/s2. */
259         public static final SIUnit SI_UNIT = SIUnit.of("kgm2/s2");
260 
261         /** Joule. */
262         public static final Energy.Unit J = new Energy.Unit("J", "joule", 1.0, UnitSystem.SI_DERIVED);
263 
264         /** The SI or BASE unit. */
265         public static final Energy.Unit SI = J.generateSiPrefixes(false, false);
266 
267         /** microjoule. */
268         public static final Energy.Unit muJ = Units.resolve(Energy.Unit.class, "muJ");
269 
270         /** millijoule. */
271         public static final Energy.Unit mJ = Units.resolve(Energy.Unit.class, "mJ");
272 
273         /** kilojoule. */
274         public static final Energy.Unit kJ = Units.resolve(Energy.Unit.class, "kJ");
275 
276         /** megajoule. */
277         public static final Energy.Unit MJ = Units.resolve(Energy.Unit.class, "MJ");
278 
279         /** gigajoule. */
280         public static final Energy.Unit GJ = Units.resolve(Energy.Unit.class, "GJ");
281 
282         /** terajoule. */
283         public static final Energy.Unit TJ = Units.resolve(Energy.Unit.class, "TJ");
284 
285         /** petajoule. */
286         public static final Energy.Unit PJ = Units.resolve(Energy.Unit.class, "PJ");
287 
288         /** foot-pound force. */
289         public static final Energy.Unit ft_lbf = J.deriveUnit("ft.lbf", "foot pound-force",
290                 Length.Unit.CONST_FT * Mass.Unit.CONST_LB * Acceleration.Unit.CONST_GRAVITY, UnitSystem.IMPERIAL);
291 
292         /** inch-pound force. */
293         public static final Energy.Unit in_lbf = J.deriveUnit("in.lbf", "inch pound-force",
294                 Length.Unit.CONST_IN * Mass.Unit.CONST_LB * Acceleration.Unit.CONST_GRAVITY, UnitSystem.IMPERIAL);
295 
296         /** British thermal unit (ISO). */
297         public static final Energy.Unit BTU_ISO =
298                 J.deriveUnit("BTU(ISO)", "British thermal unit (ISO)", 1.0545E3, UnitSystem.IMPERIAL);
299 
300         /** British thermal unit (International Table). */
301         public static final Energy.Unit BTU_IT =
302                 J.deriveUnit("BTU(IT)", "British thermal unit (Int. Table)", 1.05505585262E3, UnitSystem.IMPERIAL);
303 
304         /** calorie (International Table). */
305         public static final Energy.Unit cal_IT = J.deriveUnit("cal(IT)", "calorie (Int. Table)", 4.1868, UnitSystem.IMPERIAL);
306 
307         /** calorie. */
308         public static final Energy.Unit cal = J.deriveUnit("cal", "calorie", 4.184, UnitSystem.OTHER);
309 
310         /** kilocalorie. */
311         public static final Energy.Unit kcal = cal.deriveUnit("kcal", "kilocalorie", 1000.0, UnitSystem.OTHER);
312 
313         /** watt hour. */
314         public static final Energy.Unit Wh = new Energy.Unit("Wh", "watt hour", 3600.0, UnitSystem.SI_DERIVED);
315 
316         /** microwatt hour. */
317         public static final Energy.Unit muWh =
318                 Wh.deriveUnit("muWh", "\u03BCWh", "microwatt hour", 1E-6, UnitSystem.SI_DERIVED);
319 
320         /** milliwatt hour. */
321         public static final Energy.Unit mWh = Wh.deriveUnit("mWh", "milliwatt hour", 1E-3, UnitSystem.SI_DERIVED);
322 
323         /** kilowatt hour. */
324         public static final Energy.Unit kWh = Wh.deriveUnit("kWh", "kilowatt hour", 1E3, UnitSystem.SI_DERIVED);
325 
326         /** megawatt hour. */
327         public static final Energy.Unit MWh = Wh.deriveUnit("MWh", "megawatt hour", 1E6, UnitSystem.SI_DERIVED);
328 
329         /** gigawatt hour. */
330         public static final Energy.Unit GWh = Wh.deriveUnit("GWh", "gigawatt hour", 1E9, UnitSystem.SI_DERIVED);
331 
332         /** terawatt hour. */
333         public static final Energy.Unit TWh = Wh.deriveUnit("TWh", "terawatt hour", 1E12, UnitSystem.SI_DERIVED);
334 
335         /** petawatt hour. */
336         public static final Energy.Unit PWh = Wh.deriveUnit("PWh", "petawatt hour", 1E15, UnitSystem.SI_DERIVED);
337 
338         /** electronvolt. */
339         public static final Energy.Unit eV = new Energy.Unit("eV", "electronvolt", 1.602176634E-19, UnitSystem.SI_ACCEPTED);
340 
341         /** kilo-electronvolt. */
342         public static final Energy.Unit keV = eV.deriveUnit("keV", "kiloelectronvolt", 1E3, UnitSystem.SI_ACCEPTED);
343 
344         /** mega-electronvolt. */
345         public static final Energy.Unit MeV = eV.deriveUnit("MeV", "megaelectronvolt", 1E6, UnitSystem.SI_ACCEPTED);
346 
347         /** giga-electronvolt. */
348         public static final Energy.Unit GeV = eV.deriveUnit("GeV", "gigaelectronvolt", 1E9, UnitSystem.SI_ACCEPTED);
349 
350         /** sthene-meter (mts). */
351         public static final Energy.Unit sn_m = J.deriveUnit("sn.m", "sthene meter", 1000.0, UnitSystem.MTS);
352 
353         /** erg (cgs). */
354         public static final Energy.Unit erg = J.deriveUnit("erg", "erg", 1.0E-7, UnitSystem.CGS);
355 
356         /**
357          * Create a new Energy unit.
358          * @param id the id or main abbreviation of the unit
359          * @param name the full name of the unit
360          * @param scaleFactorToBaseUnit the scale factor of the unit to convert it TO the base (SI) unit
361          * @param unitSystem the unit system such as SI or IMPERIAL
362          */
363         public Unit(final String id, final String name, final double scaleFactorToBaseUnit, final UnitSystem unitSystem)
364         {
365             super(id, name, new LinearScale(scaleFactorToBaseUnit), unitSystem);
366         }
367 
368         /**
369          * Return a derived unit for this unit, with textual abbreviation(s) and a display abbreviation.
370          * @param textualAbbreviation the textual abbreviation of the unit, which doubles as the id
371          * @param displayAbbreviation the display abbreviation of the unit
372          * @param name the full name of the unit
373          * @param scale the scale to use to convert between this unit and the standard (e.g., SI, BASE) unit
374          * @param unitSystem unit system, e.g. SI or Imperial
375          */
376         public Unit(final String textualAbbreviation, final String displayAbbreviation, final String name, final Scale scale,
377                 final UnitSystem unitSystem)
378         {
379             super(textualAbbreviation, displayAbbreviation, name, scale, unitSystem);
380         }
381 
382         @Override
383         public SIUnit siUnit()
384         {
385             return SI_UNIT;
386         }
387 
388         @Override
389         public Unit getBaseUnit()
390         {
391             return SI;
392         }
393 
394         @Override
395         public Energy ofSi(final double si)
396         {
397             return Energy.ofSi(si);
398         }
399 
400         @Override
401         public Unit deriveUnit(final String textualAbbreviation, final String displayAbbreviation, final String name,
402                 final double scaleFactor, final UnitSystem unitSystem)
403         {
404             if (getScale() instanceof LinearScale ls)
405             {
406                 return new Energy.Unit(textualAbbreviation, displayAbbreviation, name,
407                         new LinearScale(ls.getScaleFactorToBaseUnit() * scaleFactor), unitSystem);
408             }
409             throw new UnitRuntimeException("Only possible to derive a unit from a unit with a linear scale");
410         }
411 
412     }
413 }