1 package org.djunits.unit.scale;
2
3 /**
4 * A Scale for linear transformations not involving a zero-offset, e.g. for Length, Time, Area. <br>
5 * A linear scale is a scale that is linearly relates a unit to the underlying SI standard unit. E.g. Mile is linearly related
6 * to meter (the SI unit for length) and the conversion is zero-based (0 miles equals 0 meter). Unlike temperature in degrees
7 * Celsius which is <strong>not</strong> linearly related to the Kelvin (the SI unit for temperature) because the conversion is
8 * not zero-based (0°C is 273.15K).
9 * <p>
10 * Copyright (c) 2013-2019 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved. <br>
11 * BSD-style license. See <a href="http://opentrafficsim.org/docs/license.html">OpenTrafficSim License</a>.
12 * </p>
13 * $LastChangedDate: 2015-07-24 02:58:59 +0200 (Fri, 24 Jul 2015) $, @version $Revision: 1147 $, by $Author: averbraeck $,
14 * initial version Oct 11, 2015 <br>
15 * @author <a href="http://www.tbm.tudelft.nl/averbraeck">Alexander Verbraeck</a>
16 * @author <a href="http://www.tudelft.nl/pknoppers">Peter Knoppers</a>
17 */
18 public class LinearScale implements Scale
19 {
20 /** multiply by this number to convert to the standard (e.g., SI) unit. */
21 private final double conversionFactorToStandardUnit;
22
23 /**
24 * Construct a Scale for linear transformations.
25 * @param conversionFactorToStandardUnit double; the conversion factor by which this number has to be multiplied to convert
26 * it to the standard (e.g., SI) unit.
27 */
28 public LinearScale(final double conversionFactorToStandardUnit)
29 {
30 super();
31 this.conversionFactorToStandardUnit = conversionFactorToStandardUnit;
32 }
33
34 /** {@inheritDoc} */
35 @SuppressWarnings("checkstyle:designforextension")
36 @Override
37 public double toStandardUnit(final double value)
38 {
39 return value * this.conversionFactorToStandardUnit;
40 }
41
42 /** {@inheritDoc} */
43 @SuppressWarnings("checkstyle:designforextension")
44 @Override
45 public double fromStandardUnit(final double value)
46 {
47 return value / this.conversionFactorToStandardUnit;
48 }
49
50 /**
51 * @return conversionFactorToStandardUnit
52 */
53 public final double getConversionFactorToStandardUnit()
54 {
55 return this.conversionFactorToStandardUnit;
56 }
57
58 /** {@inheritDoc} */
59 @Override
60 @SuppressWarnings("checkstyle:designforextension")
61 public boolean isBaseSIScale()
62 {
63 return this.conversionFactorToStandardUnit == 1.0;
64 }
65
66 /** {@inheritDoc} */
67 @Override
68 public int hashCode()
69 {
70 final int prime = 31;
71 int result = 1;
72 long temp;
73 temp = Double.doubleToLongBits(this.conversionFactorToStandardUnit);
74 result = prime * result + (int) (temp ^ (temp >>> 32));
75 return result;
76 }
77
78 /** {@inheritDoc} */
79 @SuppressWarnings("checkstyle:needbraces")
80 @Override
81 public boolean equals(final Object obj)
82 {
83 if (this == obj)
84 return true;
85 if (obj == null)
86 return false;
87 if (getClass() != obj.getClass())
88 return false;
89 LinearScale other = (LinearScale) obj;
90 if (Double.doubleToLongBits(this.conversionFactorToStandardUnit) != Double
91 .doubleToLongBits(other.conversionFactorToStandardUnit))
92 return false;
93 return true;
94 }
95
96 }