source: josm/trunk/src/org/openstreetmap/josm/data/SystemOfMeasurement.java@ 13142

Last change on this file since 13142 was 12846, checked in by bastiK, 7 years ago

see #15229 - use Config.getPref() wherever possible
  • Property svn:eol-style set to native
File size: 11.5 KB
Line 
1// License: GPL. For details, see LICENSE file.
2package org.openstreetmap.josm.data;
3
4import static org.openstreetmap.josm.tools.I18n.marktr;
5
6import java.text.NumberFormat;
7import java.util.Collections;
8import java.util.LinkedHashMap;
9import java.util.Locale;
10import java.util.Map;
11import java.util.Optional;
12import java.util.concurrent.CopyOnWriteArrayList;
13
14import org.openstreetmap.josm.data.preferences.StringProperty;
15import org.openstreetmap.josm.spi.preferences.Config;
16
17/**
18 * A system of units used to express length and area measurements.
19 * <p>
20 * This class also manages one globally set system of measurement stored in the {@code ProjectionPreference}
21 * @since 3406 (creation)
22 * @since 6992 (extraction in this package)
23 */
24public class SystemOfMeasurement {
25
26 /**
27 * Preferences entry for system of measurement.
28 * @since 12674 (moved from ProjectionPreference)
29 */
30 public static final StringProperty PROP_SYSTEM_OF_MEASUREMENT = new StringProperty("system_of_measurement", "Metric");
31
32 /**
33 * Interface to notify listeners of the change of the system of measurement.
34 * @since 8554
35 * @since 10600 (functional interface)
36 */
37 @FunctionalInterface
38 public interface SoMChangeListener {
39 /**
40 * The current SoM has changed.
41 * @param oldSoM The old system of measurement
42 * @param newSoM The new (current) system of measurement
43 */
44 void systemOfMeasurementChanged(String oldSoM, String newSoM);
45 }
46
47 /**
48 * Metric system (international standard).
49 * @since 3406
50 */
51 public static final SystemOfMeasurement METRIC = new SystemOfMeasurement(1, "m", 1000, "km", "km/h", 3.6, 10_000, "ha");
52
53 /**
54 * Chinese system.
55 * See <a href="https://en.wikipedia.org/wiki/Chinese_units_of_measurement#Chinese_length_units_effective_in_1930">length units</a>,
56 * <a href="https://en.wikipedia.org/wiki/Chinese_units_of_measurement#Chinese_area_units_effective_in_1930">area units</a>
57 * @since 3406
58 */
59 public static final SystemOfMeasurement CHINESE = new SystemOfMeasurement(1.0/3.0, "\u5e02\u5c3a" /* chi */, 500, "\u5e02\u91cc" /* li */,
60 "km/h", 3.6, 666.0 + 2.0/3.0, "\u4ea9" /* mu */);
61
62 /**
63 * Imperial system (British Commonwealth and former British Empire).
64 * @since 3406
65 */
66 public static final SystemOfMeasurement IMPERIAL = new SystemOfMeasurement(0.3048, "ft", 1609.344, "mi", "mph", 2.23694, 4046.86, "ac");
67
68 /**
69 * Nautical mile system (navigation, polar exploration).
70 * @since 5549
71 */
72 public static final SystemOfMeasurement NAUTICAL_MILE = new SystemOfMeasurement(185.2, "kbl", 1852, "NM", "kn", 1.94384);
73
74 /**
75 * Known systems of measurement.
76 * @since 3406
77 */
78 public static final Map<String, SystemOfMeasurement> ALL_SYSTEMS;
79 static {
80 Map<String, SystemOfMeasurement> map = new LinkedHashMap<>();
81 map.put(marktr("Metric"), METRIC);
82 map.put(marktr("Chinese"), CHINESE);
83 map.put(marktr("Imperial"), IMPERIAL);
84 map.put(marktr("Nautical Mile"), NAUTICAL_MILE);
85 ALL_SYSTEMS = Collections.unmodifiableMap(map);
86 }
87
88 private static final CopyOnWriteArrayList<SoMChangeListener> somChangeListeners = new CopyOnWriteArrayList<>();
89
90 /**
91 * Removes a global SoM change listener.
92 *
93 * @param listener the listener. Ignored if null or already absent
94 * @since 8554
95 */
96 public static void removeSoMChangeListener(SoMChangeListener listener) {
97 somChangeListeners.remove(listener);
98 }
99
100 /**
101 * Adds a SoM change listener.
102 *
103 * @param listener the listener. Ignored if null or already registered.
104 * @since 8554
105 */
106 public static void addSoMChangeListener(SoMChangeListener listener) {
107 if (listener != null) {
108 somChangeListeners.addIfAbsent(listener);
109 }
110 }
111
112 protected static void fireSoMChanged(String oldSoM, String newSoM) {
113 for (SoMChangeListener l : somChangeListeners) {
114 l.systemOfMeasurementChanged(oldSoM, newSoM);
115 }
116 }
117
118 /**
119 * Returns the current global system of measurement.
120 * @return The current system of measurement (metric system by default).
121 * @since 8554
122 */
123 public static SystemOfMeasurement getSystemOfMeasurement() {
124 return Optional.ofNullable(SystemOfMeasurement.ALL_SYSTEMS.get(PROP_SYSTEM_OF_MEASUREMENT.get()))
125 .orElse(SystemOfMeasurement.METRIC);
126 }
127
128 /**
129 * Sets the current global system of measurement.
130 * @param somKey The system of measurement key. Must be defined in {@link SystemOfMeasurement#ALL_SYSTEMS}.
131 * @throws IllegalArgumentException if {@code somKey} is not known
132 * @since 8554
133 */
134 public static void setSystemOfMeasurement(String somKey) {
135 if (!SystemOfMeasurement.ALL_SYSTEMS.containsKey(somKey)) {
136 throw new IllegalArgumentException("Invalid system of measurement: "+somKey);
137 }
138 String oldKey = PROP_SYSTEM_OF_MEASUREMENT.get();
139 if (PROP_SYSTEM_OF_MEASUREMENT.put(somKey)) {
140 fireSoMChanged(oldKey, somKey);
141 }
142 }
143
144 /** First value, in meters, used to translate unit according to above formula. */
145 public final double aValue;
146 /** Second value, in meters, used to translate unit according to above formula. */
147 public final double bValue;
148 /** First unit used to format text. */
149 public final String aName;
150 /** Second unit used to format text. */
151 public final String bName;
152 /** Speed value for the most common speed symbol, in meters per second
153 * @since 10175 */
154 public final double speedValue;
155 /** Most common speed symbol (kmh/h, mph, kn, etc.)
156 * @since 10175 */
157 public final String speedName;
158 /** Specific optional area value, in squared meters, between {@code aValue*aValue} and {@code bValue*bValue}. Set to {@code -1} if not used.
159 * @since 5870 */
160 public final double areaCustomValue;
161 /** Specific optional area unit. Set to {@code null} if not used.
162 * @since 5870 */
163 public final String areaCustomName;
164
165 /**
166 * System of measurement. Currently covers only length (and area) units.
167 *
168 * If a quantity x is given in m (x_m) and in unit a (x_a) then it translates as
169 * x_a == x_m / aValue
170 *
171 * @param aValue First value, in meters, used to translate unit according to above formula.
172 * @param aName First unit used to format text.
173 * @param bValue Second value, in meters, used to translate unit according to above formula.
174 * @param bName Second unit used to format text.
175 * @param speedName the most common speed symbol (kmh/h, mph, kn, etc.)
176 * @param speedValue the speed value for the most common speed symbol, for 1 meter per second
177 * @since 10175
178 */
179 public SystemOfMeasurement(double aValue, String aName, double bValue, String bName, String speedName, double speedValue) {
180 this(aValue, aName, bValue, bName, speedName, speedValue, -1, null);
181 }
182
183 /**
184 * System of measurement. Currently covers only length (and area) units.
185 *
186 * If a quantity x is given in m (x_m) and in unit a (x_a) then it translates as
187 * x_a == x_m / aValue
188 *
189 * @param aValue First value, in meters, used to translate unit according to above formula.
190 * @param aName First unit used to format text.
191 * @param bValue Second value, in meters, used to translate unit according to above formula.
192 * @param bName Second unit used to format text.
193 * @param speedName the most common speed symbol (kmh/h, mph, kn, etc.)
194 * @param speedValue the speed value for the most common speed symbol, for 1 meter per second
195 * @param areaCustomValue Specific optional area value, in squared meters, between {@code aValue*aValue} and {@code bValue*bValue}.
196 * Set to {@code -1} if not used.
197 * @param areaCustomName Specific optional area unit. Set to {@code null} if not used.
198 *
199 * @since 10175
200 */
201 public SystemOfMeasurement(double aValue, String aName, double bValue, String bName, String speedName, double speedValue,
202 double areaCustomValue, String areaCustomName) {
203 this.aValue = aValue;
204 this.aName = aName;
205 this.bValue = bValue;
206 this.bName = bName;
207 this.speedValue = speedValue;
208 this.speedName = speedName;
209 this.areaCustomValue = areaCustomValue;
210 this.areaCustomName = areaCustomName;
211 }
212
213 /**
214 * Returns the text describing the given distance in this system of measurement.
215 * @param dist The distance in metres
216 * @return The text describing the given distance in this system of measurement.
217 */
218 public String getDistText(double dist) {
219 return getDistText(dist, null, 0.01);
220 }
221
222 /**
223 * Returns the text describing the given distance in this system of measurement.
224 * @param dist The distance in metres
225 * @param format A {@link NumberFormat} to format the area value
226 * @param threshold Values lower than this {@code threshold} are displayed as {@code "< [threshold]"}
227 * @return The text describing the given distance in this system of measurement.
228 * @since 6422
229 */
230 public String getDistText(final double dist, final NumberFormat format, final double threshold) {
231 double a = dist / aValue;
232 if (a > bValue / aValue && !Config.getPref().getBoolean("system_of_measurement.use_only_lower_unit", false))
233 return formatText(dist / bValue, bName, format);
234 else if (a < threshold)
235 return "< " + formatText(threshold, aName, format);
236 else
237 return formatText(a, aName, format);
238 }
239
240 /**
241 * Returns the text describing the given area in this system of measurement.
242 * @param area The area in square metres
243 * @return The text describing the given area in this system of measurement.
244 * @since 5560
245 */
246 public String getAreaText(double area) {
247 return getAreaText(area, null, 0.01);
248 }
249
250 /**
251 * Returns the text describing the given area in this system of measurement.
252 * @param area The area in square metres
253 * @param format A {@link NumberFormat} to format the area value
254 * @param threshold Values lower than this {@code threshold} are displayed as {@code "< [threshold]"}
255 * @return The text describing the given area in this system of measurement.
256 * @since 6422
257 */
258 public String getAreaText(final double area, final NumberFormat format, final double threshold) {
259 double a = area / (aValue*aValue);
260 boolean lowerOnly = Config.getPref().getBoolean("system_of_measurement.use_only_lower_unit", false);
261 boolean customAreaOnly = Config.getPref().getBoolean("system_of_measurement.use_only_custom_area_unit", false);
262 if ((!lowerOnly && areaCustomValue > 0 && a > areaCustomValue / (aValue*aValue)
263 && a < (bValue*bValue) / (aValue*aValue)) || customAreaOnly)
264 return formatText(area / areaCustomValue, areaCustomName, format);
265 else if (!lowerOnly && a >= (bValue*bValue) / (aValue*aValue))
266 return formatText(area / (bValue * bValue), bName + '\u00b2', format);
267 else if (a < threshold)
268 return "< " + formatText(threshold, aName + '\u00b2', format);
269 else
270 return formatText(a, aName + '\u00b2', format);
271 }
272
273 private static String formatText(double v, String unit, NumberFormat format) {
274 if (format != null) {
275 return format.format(v) + ' ' + unit;
276 }
277 return String.format(Locale.US, v < 9.999999 ? "%.2f %s" : "%.1f %s", v, unit);
278 }
279}
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