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) 2013-2018 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 if standardUnit: the key to the locale file for the long name of the unit, otherwise the name itself
39 * @param abbreviationOrAbbreviationKey if standardUnit: the key to the locale file for the abbreviation of the unit,
40 * otherwise the abbreviation itself
41 * @param unitSystem the unit system, e.g. SI or Imperial; often the unit system for an absolute unit will be OTHER
42 * @param scaleFactorToReferenceUnit multiply by this number to convert to the standard unit
43 * @param offsetToReferenceUnit the offset to the reference unit to add to convert to the standard (e.g., BASE) unit
44 * @param standardUnit indicates whether it is a standard unit with a definition in the locale, or a user-defined unit
45 * @param relativeUnit the corresponding relative unit belonging to this absolute unit
46 */
47 protected AbsoluteLinearUnit(final String nameOrNameKey, final String abbreviationOrAbbreviationKey,
48 final UnitSystem unitSystem, final double scaleFactorToReferenceUnit, final double offsetToReferenceUnit,
49 final boolean standardUnit, final RU relativeUnit)
50 {
51 super(nameOrNameKey, abbreviationOrAbbreviationKey, unitSystem,
52 new OffsetLinearScale(scaleFactorToReferenceUnit, offsetToReferenceUnit), standardUnit);
53 this.relativeUnit = relativeUnit;
54 }
55
56 /** {@inheritDoc} */
57 @Override
58 public final OffsetLinearScale getScale()
59 {
60 return (OffsetLinearScale) super.getScale();
61 }
62
63 /** {@inheritDoc} */
64 @Override
65 public final double getOffset()
66 {
67 return getScale().getOffsetToStandardUnit();
68 }
69
70 /**
71 * Return the corresponding relative unit that belongs to this absolute unit.
72 * @return the relative unit that belongs to this absolute unit
73 */
74 public final RU getRelativeUnit()
75 {
76 return this.relativeUnit;
77 }
78
79 /** {@inheritDoc} */
80 @Override
81 public int hashCode()
82 {
83 final int prime = 31;
84 int result = super.hashCode();
85 long temp;
86 temp = Double.doubleToLongBits(this.getOffset());
87 result = prime * result + (int) (temp ^ (temp >>> 32));
88 return result;
89 }
90
91 /** {@inheritDoc} */
92 @SuppressWarnings("checkstyle:needbraces")
93 @Override
94 public boolean equals(final Object obj)
95 {
96 if (this == obj)
97 return true;
98 if (!super.equals(obj))
99 return false;
100 if (getClass() != obj.getClass())
101 return false;
102 AbsoluteLinearUnit<?, ?> other = (AbsoluteLinearUnit<?, ?>) obj;
103 if (Double.doubleToLongBits(this.getOffset()) != Double.doubleToLongBits(other.getOffset()))
104 return false;
105 return true;
106 }
107
108 /** {@inheritDoc} */
109 @SuppressWarnings("checkstyle:needbraces")
110 @Override
111 public boolean equalsIgnoreNaming(final Object obj)
112 {
113 if (this == obj)
114 return true;
115 if (!super.equals(obj))
116 return false;
117 if (getClass() != obj.getClass())
118 return false;
119 AbsoluteLinearUnit<?, ?> other = (AbsoluteLinearUnit<?, ?>) obj;
120 if (Double.doubleToLongBits(getOffset()) != Double.doubleToLongBits(other.getOffset()))
121 return false;
122 return true;
123 }
124
125 }