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1: /* Currency.java -- Representation of a currency 2: Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc. 3: 4: This file is part of GNU Classpath. 5: 6: GNU Classpath is free software; you can redistribute it and/or modify 7: it under the terms of the GNU General Public License as published by 8: the Free Software Foundation; either version 2, or (at your option) 9: any later version. 10: 11: GNU Classpath is distributed in the hope that it will be useful, but 12: WITHOUT ANY WARRANTY; without even the implied warranty of 13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14: General Public License for more details. 15: 16: You should have received a copy of the GNU General Public License 17: along with GNU Classpath; see the file COPYING. If not, write to the 18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19: 02110-1301 USA. 20: 21: Linking this library statically or dynamically with other modules is 22: making a combined work based on this library. Thus, the terms and 23: conditions of the GNU General Public License cover the whole 24: combination. 25: 26: As a special exception, the copyright holders of this library give you 27: permission to link this library with independent modules to produce an 28: executable, regardless of the license terms of these independent 29: modules, and to copy and distribute the resulting executable under 30: terms of your choice, provided that you also meet, for each linked 31: independent module, the terms and conditions of the license of that 32: module. An independent module is a module which is not derived from 33: or based on this library. If you modify this library, you may extend 34: this exception to your version of the library, but you are not 35: obligated to do so. If you do not wish to do so, delete this 36: exception statement from your version. */ 37: 38: 39: package java.util; 40: 41: import gnu.java.locale.LocaleHelper; 42: 43: import java.io.IOException; 44: import java.io.ObjectStreamException; 45: import java.io.Serializable; 46: 47: /** 48: * Representation of a currency for a particular locale. Each currency 49: * is identified by its ISO 4217 code, and only one instance of this 50: * class exists per currency. As a result, instances are created 51: * via the <code>getInstance()</code> methods rather than by using 52: * a constructor. 53: * 54: * @see java.util.Locale 55: * @author Guilhem Lavaux (guilhem.lavaux@free.fr) 56: * @author Dalibor Topic (robilad@kaffe.org) 57: * @author Bryce McKinlay (mckinlay@redhat.com) 58: * @author Andrew John Hughes (gnu_andrew@member.fsf.org) 59: * @since 1.4 60: */ 61: public final class Currency 62: implements Serializable 63: { 64: /** 65: * For compatability with Sun's JDK 66: */ 67: static final long serialVersionUID = -158308464356906721L; 68: 69: /** 70: * The set of properties which map a currency to 71: * the currency information such as the ISO 4217 72: * currency code and the number of decimal points. 73: * 74: * @see #getCurrencyCode() 75: * @serial ignored. 76: */ 77: private static transient Properties properties; 78: 79: /** 80: * The ISO 4217 currency code associated with this 81: * particular instance. 82: * 83: * @see #getCurrencyCode() 84: * @serial the ISO 4217 currency code 85: */ 86: private String currencyCode; 87: 88: /** 89: * The number of fraction digits associated with this 90: * particular instance. 91: * 92: * @see #getDefaultFractionDigits() 93: * @serial the number of fraction digits 94: */ 95: private transient int fractionDigits; 96: 97: /** 98: * A cached map of country codes 99: * instances to international currency code 100: * <code>String</code>s. Seperating this 101: * from the <code>Currency</code> instances 102: * ensures we have a common lookup between 103: * the two <code>getInstance()</code> methods. 104: * 105: * @see #getInstance(java.util.Locale) 106: * @serial ignored. 107: */ 108: private static transient Map countryMap; 109: 110: /** 111: * A cache of <code>Currency</code> instances to 112: * ensure the singleton nature of this class. The key 113: * is the international currency code. 114: * 115: * @see #getInstance(java.util.Locale) 116: * @see #getInstance(java.lang.String) 117: * @see #readResolve() 118: * @serial ignored. 119: */ 120: private static transient Map cache; 121: 122: /** 123: * Instantiates the cache and reads in the properties. 124: */ 125: static 126: { 127: /* Create a hash map for the locale mappings */ 128: countryMap = new HashMap(); 129: /* Create a hash map for the cache */ 130: cache = new HashMap(); 131: /* Create the properties object */ 132: properties = new Properties(); 133: /* Try and load the properties from our iso4217.properties resource */ 134: try 135: { 136: properties.load(Currency.class.getResourceAsStream("iso4217.properties")); 137: } 138: catch (IOException exception) 139: { 140: System.out.println("Failed to load currency resource: " + exception); 141: } 142: } 143: 144: /** 145: * Default constructor for deserialization 146: */ 147: private Currency() 148: { 149: } 150: 151: /** 152: * Constructor to create a <code>Currency</code> object 153: * for a particular <code>Locale</code>. 154: * All components of the given locale, other than the 155: * country code, are ignored. The results of calling this 156: * method may vary over time, as the currency associated with 157: * a particular country changes. For countries without 158: * a given currency (e.g. Antarctica), the result is null. 159: * 160: * @param loc the locale for the new currency, or null if 161: * there is no country code specified or a currency 162: * for this country. 163: */ 164: private Currency(Locale loc) 165: { 166: String countryCode; 167: String currencyKey; 168: String fractionDigitsKey; 169: int commaPosition; 170: 171: /* Retrieve the country code from the locale */ 172: countryCode = loc.getCountry(); 173: /* If there is no country code, return */ 174: if (countryCode.equals("")) 175: { 176: throw new 177: IllegalArgumentException("Invalid (empty) country code for locale:" 178: + loc); 179: } 180: /* Construct the key for the currency */ 181: currencyKey = countryCode + ".currency"; 182: /* Construct the key for the fraction digits */ 183: fractionDigitsKey = countryCode + ".fractionDigits"; 184: /* Retrieve the currency */ 185: currencyCode = properties.getProperty(currencyKey); 186: /* Return if the currency code is null */ 187: if (currencyCode == null) 188: { 189: return; 190: } 191: /* Split off the first currency code (we only use the first for now) */ 192: commaPosition = currencyCode.indexOf(","); 193: if (commaPosition != -1) 194: { 195: currencyCode = currencyCode.substring(0, commaPosition); 196: } 197: /* Retrieve the fraction digits */ 198: fractionDigits = Integer.parseInt(properties.getProperty(fractionDigitsKey)); 199: } 200: 201: /** 202: * Constructor for the "XXX" special case. This allows 203: * a Currency to be constructed from an assumed good 204: * currency code. 205: * 206: * @param code the code to use. 207: */ 208: private Currency(String code) 209: { 210: currencyCode = code; 211: fractionDigits = -1; /* Pseudo currency */ 212: } 213: 214: /** 215: * Returns the ISO4217 currency code of this currency. 216: * 217: * @return a <code>String</code> containing currency code. 218: */ 219: public String getCurrencyCode() 220: { 221: return currencyCode; 222: } 223: 224: /** 225: * Returns the number of digits which occur after the decimal point 226: * for this particular currency. For example, currencies such 227: * as the U.S. dollar, the Euro and the Great British pound have two 228: * digits following the decimal point to indicate the value which exists 229: * in the associated lower-valued coinage (cents in the case of the first 230: * two, pennies in the latter). Some currencies such as the Japanese 231: * Yen have no digits after the decimal point. In the case of pseudo 232: * currencies, such as IMF Special Drawing Rights, -1 is returned. 233: * 234: * @return the number of digits after the decimal separator for this currency. 235: */ 236: public int getDefaultFractionDigits() 237: { 238: return fractionDigits; 239: } 240: 241: /** 242: * Builds a new currency instance for this locale. 243: * All components of the given locale, other than the 244: * country code, are ignored. The results of calling this 245: * method may vary over time, as the currency associated with 246: * a particular country changes. For countries without 247: * a given currency (e.g. Antarctica), the result is null. 248: * 249: * @param locale a <code>Locale</code> instance. 250: * @return a new <code>Currency</code> instance. 251: * @throws NullPointerException if the locale or its 252: * country code is null. 253: * @throws IllegalArgumentException if the country of 254: * the given locale is not a supported ISO3166 code. 255: */ 256: public static Currency getInstance(Locale locale) 257: { 258: /** 259: * The new instance must be the only available instance 260: * for the currency it supports. We ensure this happens, 261: * while maintaining a suitable performance level, by 262: * creating the appropriate object on the first call to 263: * this method, and returning the cached instance on 264: * later calls. 265: */ 266: Currency newCurrency; 267: 268: String country = locale.getCountry(); 269: if (locale == null || country == null) 270: { 271: throw new 272: NullPointerException("The locale or its country is null."); 273: } 274: /* Attempt to get the currency from the cache */ 275: String code = (String) countryMap.get(country); 276: if (code == null) 277: { 278: /* Create the currency for this locale */ 279: newCurrency = new Currency(locale); 280: /* 281: * If the currency code is null, then creation failed 282: * and we return null. 283: */ 284: code = newCurrency.getCurrencyCode(); 285: if (code == null) 286: { 287: return null; 288: } 289: else 290: { 291: /* Cache it */ 292: countryMap.put(country, code); 293: cache.put(code, newCurrency); 294: } 295: } 296: else 297: { 298: newCurrency = (Currency) cache.get(code); 299: } 300: /* Return the instance */ 301: return newCurrency; 302: } 303: 304: /** 305: * Builds the currency corresponding to the specified currency code. 306: * 307: * @param currencyCode a string representing a currency code. 308: * @return a new <code>Currency</code> instance. 309: * @throws NullPointerException if currencyCode is null. 310: * @throws IllegalArgumentException if the supplied currency code 311: * is not a supported ISO 4217 code. 312: */ 313: public static Currency getInstance(String currencyCode) 314: { 315: Locale[] allLocales; 316: 317: /* 318: * Throw a null pointer exception explicitly if currencyCode is null. 319: * One is not thrown otherwise. It results in an 320: * IllegalArgumentException. 321: */ 322: if (currencyCode == null) 323: { 324: throw new NullPointerException("The supplied currency code is null."); 325: } 326: /* Nasty special case to allow an erroneous currency... blame Sun */ 327: if (currencyCode.equals("XXX")) 328: return new Currency("XXX"); 329: Currency newCurrency = (Currency) cache.get(currencyCode); 330: if (newCurrency == null) 331: { 332: /* Get all locales */ 333: allLocales = Locale.getAvailableLocales(); 334: /* Loop through each locale, looking for the code */ 335: for (int i = 0;i < allLocales.length; i++) 336: { 337: try 338: { 339: Currency testCurrency = getInstance (allLocales[i]); 340: if (testCurrency != null && 341: testCurrency.getCurrencyCode().equals(currencyCode)) 342: { 343: return testCurrency; 344: } 345: } 346: catch (IllegalArgumentException exception) 347: { 348: /* Ignore locales without valid countries */ 349: } 350: } 351: /* 352: * If we get this far, the code is not supported by any of 353: * our locales. 354: */ 355: throw new IllegalArgumentException("The currency code, " + currencyCode + 356: ", is not supported."); 357: } 358: else 359: { 360: return newCurrency; 361: } 362: } 363: 364: /** 365: * This method returns the symbol which precedes or follows a 366: * value in this particular currency in the default locale. 367: * In cases where there is no such symbol for the currency, 368: * the ISO 4217 currency code is returned. 369: * 370: * @return the currency symbol, or the ISO 4217 currency code if 371: * one doesn't exist. 372: */ 373: public String getSymbol() 374: { 375: return getSymbol(Locale.getDefault()); 376: } 377: 378: /** 379: * <p> 380: * This method returns the symbol which precedes or follows a 381: * value in this particular currency. The returned value is 382: * the symbol used to denote the currency in the specified locale. 383: * </p> 384: * <p> 385: * For example, a supplied locale may specify a different symbol 386: * for the currency, due to conflicts with its own currency. 387: * This would be the case with the American currency, the dollar. 388: * Locales that also use a dollar-based currency (e.g. Canada, Australia) 389: * need to differentiate the American dollar using 'US$' rather than '$'. 390: * So, supplying one of these locales to <code>getSymbol()</code> would 391: * return this value, rather than the standard '$'. 392: * </p> 393: * <p> 394: * In cases where there is no such symbol for a particular currency, 395: * the ISO 4217 currency code is returned. 396: * </p> 397: * 398: * @param locale the locale to express the symbol in. 399: * @return the currency symbol, or the ISO 4217 currency code if 400: * one doesn't exist. 401: * @throws NullPointerException if the locale is null. 402: */ 403: public String getSymbol(Locale locale) 404: { 405: return LocaleHelper.getLocalizedString(locale, currencyCode, 406: "currenciesSymbol", false, true); 407: } 408: 409: /** 410: * Returns the international ISO4217 currency code of this currency. 411: * 412: * @return a <code>String</code> containing the ISO4217 currency code. 413: */ 414: public String toString() 415: { 416: return getCurrencyCode(); 417: } 418: 419: /** 420: * Resolves the deserialized object to the singleton instance for its 421: * particular currency. The currency code of the deserialized instance 422: * is used to return the correct instance. 423: * 424: * @return the singleton instance for the currency specified by the 425: * currency code of the deserialized object. This replaces 426: * the deserialized object as the returned object from 427: * deserialization. 428: * @throws ObjectStreamException if a problem occurs with deserializing 429: * the object. 430: */ 431: private Object readResolve() 432: throws ObjectStreamException 433: { 434: return getInstance(currencyCode); 435: } 436: 437: }
GNU Classpath (0.20) |