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1   package org.djunits.unit;
2   
3   import static org.djunits.unit.unitsystem.UnitSystem.SI_DERIVED;
4   
5   import org.djunits.unit.unitsystem.UnitSystem;
6   
7   /**
8    * Standard solid angle unit.
9    * <p>
10   * Copyright (c) 2015-2018 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved. <br>
11   * BSD-style license. See <a href="http://djunits.org/docs/license.html">DJUNITS License</a>.
12   * <p>
13   * $LastChangedDate: 2018-01-28 03:17:44 +0100 (Sun, 28 Jan 2018) $, @version $Revision: 256 $, by $Author: averbraeck $,
14   * initial version May 15, 2014 <br>
15   * @author <a href="http://www.tbm.tudelft.nl/averbraeck">Alexander Verbraeck</a>
16   */
17  public class AngleSolidUnit extends LinearUnit<AngleSolidUnit>
18  {
19      /** */
20      private static final long serialVersionUID = 20140607L;
21  
22      /** The SI unit for solid angle is steradian. */
23      public static final AngleSolidUnit SI;
24  
25      /** steradian. */
26      public static final AngleSolidUnit STERADIAN;
27  
28      /** square degree. */
29      public static final AngleSolidUnit SQUARE_DEGREE;
30  
31      static
32      {
33          SI = new AngleSolidUnit("AngleSolidUnit.steradian", "AngleSolidUnit.sr", SI_DERIVED);
34          STERADIAN = SI;
35          SQUARE_DEGREE = new AngleSolidUnit("AngleSolidUnit.square_degree", "AngleSolidUnit.sq_deg", SI_DERIVED, STERADIAN,
36                  (Math.PI / 180.0) * (Math.PI / 180.0), true);
37      }
38  
39      /**
40       * Build a standard unit.
41       * @param nameKey the key to the locale file for the long name of the unit
42       * @param abbreviationKey the key to the locale file for the abbreviation of the unit
43       * @param unitSystem the unit system, e.g. SI or Imperial
44       */
45      private AngleSolidUnit(final String nameKey, final String abbreviationKey, final UnitSystem unitSystem)
46      {
47          super(nameKey, abbreviationKey, unitSystem, true);
48      }
49  
50      /**
51       * Construct a derived unit as a conversion from another unit.
52       * @param nameOrNameKey if standardUnit: the key to the locale file for the long name of the unit, otherwise the name itself
53       * @param abbreviationOrAbbreviationKey if standardUnit: the key to the locale file for the abbreviation of the unit,
54       *            otherwise the abbreviation itself
55       * @param unitSystem the unit system, e.g. SI or Imperial
56       * @param referenceUnit the unit to convert to
57       * @param scaleFactorToReferenceUnit multiply a value in this unit by the factor to convert to the given reference unit
58       * @param standardUnit indicates whether it is a standard unit with a definition in the locale, or a user-defined unit
59       */
60      private AngleSolidUnit(final String nameOrNameKey, final String abbreviationOrAbbreviationKey, final UnitSystem unitSystem,
61              final AngleSolidUnit referenceUnit, final double scaleFactorToReferenceUnit, final boolean standardUnit)
62      {
63          super(nameOrNameKey, abbreviationOrAbbreviationKey, unitSystem, referenceUnit, scaleFactorToReferenceUnit,
64                  standardUnit);
65      }
66  
67      /**
68       * Build a user-defined unit with a conversion factor to another unit.
69       * @param name the long name of the unit
70       * @param abbreviation the abbreviation of the unit
71       * @param unitSystem the unit system, e.g. SI or Imperial
72       * @param referenceUnit the unit to convert to
73       * @param scaleFactorToReferenceUnit multiply a value in this unit by the factor to convert to the given reference unit
74       */
75      public AngleSolidUnit(final String name, final String abbreviation, final UnitSystem unitSystem,
76              final AngleSolidUnit referenceUnit, final double scaleFactorToReferenceUnit)
77      {
78          this(name, abbreviation, unitSystem, referenceUnit, scaleFactorToReferenceUnit, false);
79      }
80  
81      /** {@inheritDoc} */
82      @Override
83      public final AngleSolidUnit getStandardUnit()
84      {
85          return STERADIAN;
86      }
87  
88      /** {@inheritDoc} */
89      @Override
90      public final String getSICoefficientsString()
91      {
92          return "1";
93      }
94  
95  }