1 package org.djunits.unit;
2
3 import org.djunits.unit.scale.OffsetLinearScale;
4 import org.djunits.unit.unitsystem.UnitSystem;
5
6 /**
7 * An absolute unit is a unit that needs to be defined with a "distance" to the reference absolute unit. E.g., for Time, an
8 * absolute reference unit has to be chosen such as an Epoch (e.g., 0001-01-01 AD at 00:00), where other TimeUnits can be
9 * defined relative to that reference unit (e.g., POSIX time, 1-1-1970 at 00:00, which is 719162 days after the reference time).
10 * <p>
11 * An absolute unit is always a unit with an OffsetLinearScale. The offset defines how far away the origin of that absolute unit
12 * is compared to the base unit. The linear scale indicates in what default "steps" compared to the reference relative scale the
13 * absolute scale is used. For temperature, this is very clear. Degrees Celcius is shifted 273.15 compared to the origin of the
14 * Kelvin scale, and the linear unit is 1 (relatively, 1 Kelvin is one degree Celcius). For Degree Fahrenheit, the linear scale
15 * is 5/9, and the offset is 459.67. For Direction, North can be chosen as 0, and radians (SI) as the default angle. But one
16 * could also define a NORTH_DEGREES absolute direction unit, or a WEST_RADIANS one. Similar choices can be made for time and
17 * position.
18 * <p>
19 * Copyright (c) 2013-2019 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved. <br>
20 * BSD-style license. See <a href="http://djunits.org/docs/license.html">DJUNITS License</a>.
21 * </p>
22 * $LastChangedDate: 2015-07-24 02:58:59 +0200 (Fri, 24 Jul 2015) $, @version $Revision: 1147 $, by $Author: averbraeck $,
23 * initial version Apr 27, 2017 <br>
24 * @author <a href="http://www.tbm.tudelft.nl/averbraeck">Alexander Verbraeck</a>
25 * @param <AU> the absolute unit.
26 * @param <RU> the correcponding relative unit
27 */
28 public abstract class AbsoluteLinearUnit<AU extends LinearUnit<AU>, RU extends Unit<RU>> extends LinearUnit<AU>
29 implements AbsoluteUnit
30 {
31 /** */
32 private static final long serialVersionUID = 20170427L;
33
34 /** the corresponding relative unit belonging to this absolute unit. */
35 private final RU relativeUnit;
36
37 /**
38 * @param nameOrNameKey String; if standardUnit: the key to the locale file for the long name of the unit, otherwise the
39 * name itself
40 * @param abbreviationOrAbbreviationKey String; if standardUnit: the key to the locale file for the abbreviation of the
41 * unit, otherwise the abbreviation itself
42 * @param unitSystem the unit system, e.g. SI or Imperial; often the unit system for an absolute unit will be OTHER
43 * @param scaleFactorToReferenceUnit double; multiply by this number to convert to the standard unit
44 * @param offsetToReferenceUnit double; the offset to the reference unit to add to convert to the standard (e.g., BASE) unit
45 * @param standardUnit boolean; indicates whether it is a standard unit with a definition in the locale, or a user-defined
46 * unit
47 * @param relativeUnit RU; the corresponding relative unit belonging to this absolute unit
48 */
49 protected AbsoluteLinearUnit(final String nameOrNameKey, final String abbreviationOrAbbreviationKey,
50 final UnitSystem unitSystem, final double scaleFactorToReferenceUnit, final double offsetToReferenceUnit,
51 final boolean standardUnit, final RU relativeUnit)
52 {
53 super(nameOrNameKey, abbreviationOrAbbreviationKey, unitSystem,
54 new OffsetLinearScale(scaleFactorToReferenceUnit, offsetToReferenceUnit), standardUnit);
55 this.relativeUnit = relativeUnit;
56 }
57
58 /** {@inheritDoc} */
59 @Override
60 public final OffsetLinearScale getScale()
61 {
62 return (OffsetLinearScale) super.getScale();
63 }
64
65 /** {@inheritDoc} */
66 @Override
67 public final double getOffset()
68 {
69 return getScale().getOffsetToStandardUnit();
70 }
71
72 /**
73 * Return the corresponding relative unit that belongs to this absolute unit.
74 * @return the relative unit that belongs to this absolute unit
75 */
76 public final RU getRelativeUnit()
77 {
78 return this.relativeUnit;
79 }
80
81 /** {@inheritDoc} */
82 @Override
83 public int hashCode()
84 {
85 final int prime = 31;
86 int result = super.hashCode();
87 long temp;
88 temp = Double.doubleToLongBits(this.getOffset());
89 result = prime * result + (int) (temp ^ (temp >>> 32));
90 return result;
91 }
92
93 /** {@inheritDoc} */
94 @SuppressWarnings("checkstyle:needbraces")
95 @Override
96 public boolean equals(final Object obj)
97 {
98 if (this == obj)
99 return true;
100 if (!super.equals(obj))
101 return false;
102 if (getClass() != obj.getClass())
103 return false;
104 AbsoluteLinearUnit<?, ?> other = (AbsoluteLinearUnit<?, ?>) obj;
105 if (Double.doubleToLongBits(this.getOffset()) != Double.doubleToLongBits(other.getOffset()))
106 return false;
107 return true;
108 }
109
110 /** {@inheritDoc} */
111 @SuppressWarnings("checkstyle:needbraces")
112 @Override
113 public boolean equalsIgnoreNaming(final Object obj)
114 {
115 if (this == obj)
116 return true;
117 if (!super.equals(obj))
118 return false;
119 if (getClass() != obj.getClass())
120 return false;
121 AbsoluteLinearUnit<?, ?> other = (AbsoluteLinearUnit<?, ?>) obj;
122 if (Double.doubleToLongBits(getOffset()) != Double.doubleToLongBits(other.getOffset()))
123 return false;
124 return true;
125 }
126
127 }