/*
 * Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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package java.util;

import java.io.BufferedInputStream;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileReader;
import java.io.InputStream;
import java.io.IOException;
import java.io.Serializable;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.regex.Pattern;
import java.util.regex.Matcher;
import java.util.spi.CurrencyNameProvider;
import java.util.stream.Collectors;

import jdk.internal.util.StaticProperty;
import sun.util.locale.provider.CalendarDataUtility;
import sun.util.locale.provider.LocaleServiceProviderPool;
import sun.util.logging.PlatformLogger;


/**
 * Represents a currency. Currencies are identified by their ISO 4217 currency
 * codes. Visit the <a href="http://www.iso.org/iso/home/standards/currency_codes.htm">
 * ISO web site</a> for more information.
 * <p>
 * The class is designed so that there's never more than one
 * <code>Currency</code> instance for any given currency. Therefore, there's
 * no public constructor. You obtain a <code>Currency</code> instance using
 * the <code>getInstance</code> methods.
 * <p>
 * Users can supersede the Java runtime currency data by means of the system
 * property {@code java.util.currency.data}. If this system property is
 * defined then its value is the location of a properties file, the contents of
 * which are key/value pairs of the ISO 3166 country codes and the ISO 4217
 * currency data respectively. The value part consists of three ISO 4217 values
 * of a currency, i.e., an alphabetic code, a numeric code, and a minor unit.
 * Those three ISO 4217 values are separated by commas.
 * The lines which start with '#'s are considered comment lines. An optional UTC
 * timestamp may be specified per currency entry if users need to specify a
 * cutover date indicating when the new data comes into effect. The timestamp is
 * appended to the end of the currency properties and uses a comma as a separator.
 * If a UTC datestamp is present and valid, the JRE will only use the new currency
 * properties if the current UTC date is later than the date specified at class
 * loading time. The format of the timestamp must be of ISO 8601 format :
 * {@code 'yyyy-MM-dd'T'HH:mm:ss'}. For example,
 * <p>
 * <code>
 * #Sample currency properties<br>
 * JP=JPZ,999,0
 * </code>
 * <p>
 * will supersede the currency data for Japan. If JPZ is one of the existing
 * ISO 4217 currency code referred by other countries, the existing
 * JPZ currency data is updated with the given numeric code and minor
 * unit value.
 *
 * <p>
 * <code>
 * #Sample currency properties with cutover date<br>
 * JP=JPZ,999,0,2014年01月01日T00:00:00
 * </code>
 * <p>
 * will supersede the currency data for Japan if {@code Currency} class is loaded after
 * 1st January 2014 00:00:00 GMT.
 * <p>
 * Where syntactically malformed entries are encountered, the entry is ignored
 * and the remainder of entries in file are processed. For instances where duplicate
 * country code entries exist, the behavior of the Currency information for that
 * {@code Currency} is undefined and the remainder of entries in file are processed.
 * <p>
 * If multiple property entries with same currency code but different numeric code
 * and/or minor unit are encountered, those entries are ignored and the remainder
 * of entries in file are processed.
 *
 * <p>
 * It is recommended to use {@link java.math.BigDecimal} class while dealing
 * with {@code Currency} or monetary values as it provides better handling of floating
 * point numbers and their operations.
 *
 * @see java.math.BigDecimal
 * @since 1.4
 */
public final class Currency implements Serializable {

 private static final long serialVersionUID = -158308464356906721L;

 /**
 * ISO 4217 currency code for this currency.
 *
 * @serial
 */
 private final String currencyCode;

 /**
 * Default fraction digits for this currency.
 * Set from currency data tables.
 */
 private final transient int defaultFractionDigits;

 /**
 * ISO 4217 numeric code for this currency.
 * Set from currency data tables.
 */
 private final transient int numericCode;


 // class data: instance map

 private static ConcurrentMap<String, Currency> instances = new ConcurrentHashMap<>(7);
 private static HashSet<Currency> available;

 // Class data: currency data obtained from currency.data file.
 // Purpose:
 // - determine valid country codes
 // - determine valid currency codes
 // - map country codes to currency codes
 // - obtain default fraction digits for currency codes
 //
 // sc = special case; dfd = default fraction digits
 // Simple countries are those where the country code is a prefix of the
 // currency code, and there are no known plans to change the currency.
 //
 // table formats:
 // - mainTable:
 // - maps country code to 32-bit int
 // - 26*26 entries, corresponding to [A-Z]*[A-Z]
 // - \u007F -> not valid country
 // - bits 20-31: unused
 // - bits 10-19: numeric code (0 to 1023)
 // - bit 9: 1 - special case, bits 0-4 indicate which one
 // 0 - simple country, bits 0-4 indicate final char of currency code
 // - bits 5-8: fraction digits for simple countries, 0 for special cases
 // - bits 0-4: final char for currency code for simple country, or ID of special case
 // - special case IDs:
 // - 0: country has no currency
 // - other: index into specialCasesList

 static int formatVersion;
 static int dataVersion;
 static int[] mainTable;
 static List<SpecialCaseEntry> specialCasesList;
 static List<OtherCurrencyEntry> otherCurrenciesList;

 // handy constants - must match definitions in GenerateCurrencyData
 // magic number
 private static final int MAGIC_NUMBER = 0x43757244;
 // number of characters from A to Z
 private static final int A_TO_Z = ('Z' - 'A') + 1;
 // entry for invalid country codes
 private static final int INVALID_COUNTRY_ENTRY = 0x0000007F;
 // entry for countries without currency
 private static final int COUNTRY_WITHOUT_CURRENCY_ENTRY = 0x00000200;
 // mask for simple case country entries
 private static final int SIMPLE_CASE_COUNTRY_MASK = 0x00000000;
 // mask for simple case country entry final character
 private static final int SIMPLE_CASE_COUNTRY_FINAL_CHAR_MASK = 0x0000001F;
 // mask for simple case country entry default currency digits
 private static final int SIMPLE_CASE_COUNTRY_DEFAULT_DIGITS_MASK = 0x000001E0;
 // shift count for simple case country entry default currency digits
 private static final int SIMPLE_CASE_COUNTRY_DEFAULT_DIGITS_SHIFT = 5;
 // maximum number for simple case country entry default currency digits
 private static final int SIMPLE_CASE_COUNTRY_MAX_DEFAULT_DIGITS = 9;
 // mask for special case country entries
 private static final int SPECIAL_CASE_COUNTRY_MASK = 0x00000200;
 // mask for special case country index
 private static final int SPECIAL_CASE_COUNTRY_INDEX_MASK = 0x0000001F;
 // delta from entry index component in main table to index into special case tables
 private static final int SPECIAL_CASE_COUNTRY_INDEX_DELTA = 1;
 // mask for distinguishing simple and special case countries
 private static final int COUNTRY_TYPE_MASK = SIMPLE_CASE_COUNTRY_MASK | SPECIAL_CASE_COUNTRY_MASK;
 // mask for the numeric code of the currency
 private static final int NUMERIC_CODE_MASK = 0x000FFC00;
 // shift count for the numeric code of the currency
 private static final int NUMERIC_CODE_SHIFT = 10;

 // Currency data format version
 private static final int VALID_FORMAT_VERSION = 3;

 static {
 AccessController.doPrivileged(new PrivilegedAction<>() {
 @Override
 public Void run() {
 try {
 try (InputStream in = getClass().getResourceAsStream("/java/util/currency.data")) {
 if (in == null) {
 throw new InternalError("Currency data not found");
 }
 DataInputStream dis = new DataInputStream(new BufferedInputStream(in));
 if (dis.readInt() != MAGIC_NUMBER) {
 throw new InternalError("Currency data is possibly corrupted");
 }
 formatVersion = dis.readInt();
 if (formatVersion != VALID_FORMAT_VERSION) {
 throw new InternalError("Currency data format is incorrect");
 }
 dataVersion = dis.readInt();
 mainTable = readIntArray(dis, A_TO_Z * A_TO_Z);
 int scCount = dis.readInt();
 specialCasesList = readSpecialCases(dis, scCount);
 int ocCount = dis.readInt();
 otherCurrenciesList = readOtherCurrencies(dis, ocCount);
 }
 } catch (IOException e) {
 throw new InternalError(e);
 }

 // look for the properties file for overrides
 String propsFile = System.getProperty("java.util.currency.data");
 if (propsFile == null) {
 propsFile = StaticProperty.javaHome() + File.separator + "lib" +
 File.separator + "currency.properties";
 }
 try {
 File propFile = new File(propsFile);
 if (propFile.exists()) {
 Properties props = new Properties();
 try (FileReader fr = new FileReader(propFile)) {
 props.load(fr);
 }
 Pattern propertiesPattern =
 Pattern.compile("([A-Z]{3})\\s*,\\s*(\\d{3})\\s*,\\s*" +
 "(\\d+)\\s*,?\\s*(\\d{4}-\\d{2}-\\d{2}T\\d{2}:" +
 "\\d{2}:\\d{2})?");
 List<CurrencyProperty> currencyEntries
 = getValidCurrencyData(props, propertiesPattern);
 currencyEntries.forEach(Currency::replaceCurrencyData);
 }
 } catch (IOException e) {
 CurrencyProperty.info("currency.properties is ignored"
 + " because of an IOException", e);
 }
 return null;
 }
 });
 }

 /**
 * Constants for retrieving localized names from the name providers.
 */
 private static final int SYMBOL = 0;
 private static final int DISPLAYNAME = 1;


 /**
 * Constructs a <code>Currency</code> instance. The constructor is private
 * so that we can insure that there's never more than one instance for a
 * given currency.
 */
 private Currency(String currencyCode, int defaultFractionDigits, int numericCode) {
 this.currencyCode = currencyCode;
 this.defaultFractionDigits = defaultFractionDigits;
 this.numericCode = numericCode;
 }

 /**
 * Returns the <code>Currency</code> instance for the given currency code.
 *
 * @param currencyCode the ISO 4217 code of the currency
 * @return the <code>Currency</code> instance for the given currency code
 * @exception NullPointerException if <code>currencyCode</code> is null
 * @exception IllegalArgumentException if <code>currencyCode</code> is not
 * a supported ISO 4217 code.
 */
 public static Currency getInstance(String currencyCode) {
 return getInstance(currencyCode, Integer.MIN_VALUE, 0);
 }

 private static Currency getInstance(String currencyCode, int defaultFractionDigits,
 int numericCode) {
 // Try to look up the currency code in the instances table.
 // This does the null pointer check as a side effect.
 // Also, if there already is an entry, the currencyCode must be valid.
 Currency instance = instances.get(currencyCode);
 if (instance != null) {
 return instance;
 }

 if (defaultFractionDigits == Integer.MIN_VALUE) {
 // Currency code not internally generated, need to verify first
 // A currency code must have 3 characters and exist in the main table
 // or in the list of other currencies.
 boolean found = false;
 if (currencyCode.length() != 3) {
 throw new IllegalArgumentException();
 }
 char char1 = currencyCode.charAt(0);
 char char2 = currencyCode.charAt(1);
 int tableEntry = getMainTableEntry(char1, char2);
 if ((tableEntry & COUNTRY_TYPE_MASK) == SIMPLE_CASE_COUNTRY_MASK
 && tableEntry != INVALID_COUNTRY_ENTRY
 && currencyCode.charAt(2) - 'A' == (tableEntry & SIMPLE_CASE_COUNTRY_FINAL_CHAR_MASK)) {
 defaultFractionDigits = (tableEntry & SIMPLE_CASE_COUNTRY_DEFAULT_DIGITS_MASK) >> SIMPLE_CASE_COUNTRY_DEFAULT_DIGITS_SHIFT;
 numericCode = (tableEntry & NUMERIC_CODE_MASK) >> NUMERIC_CODE_SHIFT;
 found = true;
 } else { //special case
 int[] fractionAndNumericCode = SpecialCaseEntry.findEntry(currencyCode);
 if (fractionAndNumericCode != null) {
 defaultFractionDigits = fractionAndNumericCode[0];
 numericCode = fractionAndNumericCode[1];
 found = true;
 }
 }

 if (!found) {
 OtherCurrencyEntry ocEntry = OtherCurrencyEntry.findEntry(currencyCode);
 if (ocEntry == null) {
 throw new IllegalArgumentException();
 }
 defaultFractionDigits = ocEntry.fraction;
 numericCode = ocEntry.numericCode;
 }
 }

 Currency currencyVal =
 new Currency(currencyCode, defaultFractionDigits, numericCode);
 instance = instances.putIfAbsent(currencyCode, currencyVal);
 return (instance != null ? instance : currencyVal);
 }

 /**
 * Returns the <code>Currency</code> instance for the country of the
 * given locale. The language and variant components of the locale
 * are ignored. The result may vary over time, as countries change their
 * currencies. For example, for the original member countries of the
 * European Monetary Union, the method returns the old national currencies
 * until December 31, 2001, and the Euro from January 1, 2002, local time
 * of the respective countries.
 * <p>
 * If the specified {@code locale} contains "cu" and/or "rg"
 * <a href="./Locale.html#def_locale_extension">Unicode extensions</a>,
 * the instance returned from this method reflects
 * the values specified with those extensions. If both "cu" and "rg" are
 * specified, the currency from the "cu" extension supersedes the implicit one
 * from the "rg" extension.
 * <p>
 * The method returns <code>null</code> for territories that don't
 * have a currency, such as Antarctica.
 *
 * @param locale the locale for whose country a <code>Currency</code>
 * instance is needed
 * @return the <code>Currency</code> instance for the country of the given
 * locale, or {@code null}
 * @exception NullPointerException if <code>locale</code>
 * is {@code null}
 * @exception IllegalArgumentException if the country of the given {@code locale}
 * is not a supported ISO 3166 country code.
 */
 public static Currency getInstance(Locale locale) {
 // check for locale overrides
 String override = locale.getUnicodeLocaleType("cu");
 if (override != null) {
 try {
 return getInstance(override.toUpperCase(Locale.ROOT));
 } catch (IllegalArgumentException iae) {
 // override currency is invalid. Fall through.
 }
 }

 String country = CalendarDataUtility.findRegionOverride(locale).getCountry();

 if (country == null || !country.matches("^[a-zA-Z]{2}$")) {
 throw new IllegalArgumentException();
 }

 char char1 = country.charAt(0);
 char char2 = country.charAt(1);
 int tableEntry = getMainTableEntry(char1, char2);
 if ((tableEntry & COUNTRY_TYPE_MASK) == SIMPLE_CASE_COUNTRY_MASK
 && tableEntry != INVALID_COUNTRY_ENTRY) {
 char finalChar = (char) ((tableEntry & SIMPLE_CASE_COUNTRY_FINAL_CHAR_MASK) + 'A');
 int defaultFractionDigits = (tableEntry & SIMPLE_CASE_COUNTRY_DEFAULT_DIGITS_MASK) >> SIMPLE_CASE_COUNTRY_DEFAULT_DIGITS_SHIFT;
 int numericCode = (tableEntry & NUMERIC_CODE_MASK) >> NUMERIC_CODE_SHIFT;
 StringBuilder sb = new StringBuilder(country);
 sb.append(finalChar);
 return getInstance(sb.toString(), defaultFractionDigits, numericCode);
 } else {
 // special cases
 if (tableEntry == INVALID_COUNTRY_ENTRY) {
 throw new IllegalArgumentException();
 }
 if (tableEntry == COUNTRY_WITHOUT_CURRENCY_ENTRY) {
 return null;
 } else {
 int index = SpecialCaseEntry.toIndex(tableEntry);
 SpecialCaseEntry scEntry = specialCasesList.get(index);
 if (scEntry.cutOverTime == Long.MAX_VALUE
 || System.currentTimeMillis() < scEntry.cutOverTime) {
 return getInstance(scEntry.oldCurrency,
 scEntry.oldCurrencyFraction,
 scEntry.oldCurrencyNumericCode);
 } else {
 return getInstance(scEntry.newCurrency,
 scEntry.newCurrencyFraction,
 scEntry.newCurrencyNumericCode);
 }
 }
 }
 }

 /**
 * Gets the set of available currencies. The returned set of currencies
 * contains all of the available currencies, which may include currencies
 * that represent obsolete ISO 4217 codes. The set can be modified
 * without affecting the available currencies in the runtime.
 *
 * @return the set of available currencies. If there is no currency
 * available in the runtime, the returned set is empty.
 * @since 1.7
 */
 public static Set<Currency> getAvailableCurrencies() {
 synchronized(Currency.class) {
 if (available == null) {
 available = new HashSet<>(256);

 // Add simple currencies first
 for (char c1 = 'A'; c1 <= 'Z'; c1 ++) {
 for (char c2 = 'A'; c2 <= 'Z'; c2 ++) {
 int tableEntry = getMainTableEntry(c1, c2);
 if ((tableEntry & COUNTRY_TYPE_MASK) == SIMPLE_CASE_COUNTRY_MASK
 && tableEntry != INVALID_COUNTRY_ENTRY) {
 char finalChar = (char) ((tableEntry & SIMPLE_CASE_COUNTRY_FINAL_CHAR_MASK) + 'A');
 int defaultFractionDigits = (tableEntry & SIMPLE_CASE_COUNTRY_DEFAULT_DIGITS_MASK) >> SIMPLE_CASE_COUNTRY_DEFAULT_DIGITS_SHIFT;
 int numericCode = (tableEntry & NUMERIC_CODE_MASK) >> NUMERIC_CODE_SHIFT;
 StringBuilder sb = new StringBuilder();
 sb.append(c1);
 sb.append(c2);
 sb.append(finalChar);
 available.add(getInstance(sb.toString(), defaultFractionDigits, numericCode));
 } else if ((tableEntry & COUNTRY_TYPE_MASK) == SPECIAL_CASE_COUNTRY_MASK
 && tableEntry != INVALID_COUNTRY_ENTRY
 && tableEntry != COUNTRY_WITHOUT_CURRENCY_ENTRY) {
 int index = SpecialCaseEntry.toIndex(tableEntry);
 SpecialCaseEntry scEntry = specialCasesList.get(index);

 if (scEntry.cutOverTime == Long.MAX_VALUE
 || System.currentTimeMillis() < scEntry.cutOverTime) {
 available.add(getInstance(scEntry.oldCurrency,
 scEntry.oldCurrencyFraction,
 scEntry.oldCurrencyNumericCode));
 } else {
 available.add(getInstance(scEntry.newCurrency,
 scEntry.newCurrencyFraction,
 scEntry.newCurrencyNumericCode));
 }
 }
 }
 }

 // Now add other currencies
 for (OtherCurrencyEntry entry : otherCurrenciesList) {
 available.add(getInstance(entry.currencyCode));
 }
 }
 }

 @SuppressWarnings("unchecked")
 Set<Currency> result = (Set<Currency>) available.clone();
 return result;
 }

 /**
 * Gets the ISO 4217 currency code of this currency.
 *
 * @return the ISO 4217 currency code of this currency.
 */
 public String getCurrencyCode() {
 return currencyCode;
 }

 /**
 * Gets the symbol of this currency for the default
 * {@link Locale.Category#DISPLAY DISPLAY} locale.
 * For example, for the US Dollar, the symbol is "$" if the default
 * locale is the US, while for other locales it may be "US$". If no
 * symbol can be determined, the ISO 4217 currency code is returned.
 * <p>
 * If the default {@link Locale.Category#DISPLAY DISPLAY} locale
 * contains "rg" (region override)
 * <a href="./Locale.html#def_locale_extension">Unicode extension</a>,
 * the symbol returned from this method reflects
 * the value specified with that extension.
 * <p>
 * This is equivalent to calling
 * {@link #getSymbol(Locale)
 * getSymbol(Locale.getDefault(Locale.Category.DISPLAY))}.
 *
 * @return the symbol of this currency for the default
 * {@link Locale.Category#DISPLAY DISPLAY} locale
 */
 public String getSymbol() {
 return getSymbol(Locale.getDefault(Locale.Category.DISPLAY));
 }

 /**
 * Gets the symbol of this currency for the specified locale.
 * For example, for the US Dollar, the symbol is "$" if the specified
 * locale is the US, while for other locales it may be "US$". If no
 * symbol can be determined, the ISO 4217 currency code is returned.
 * <p>
 * If the specified {@code locale} contains "rg" (region override)
 * <a href="./Locale.html#def_locale_extension">Unicode extension</a>,
 * the symbol returned from this method reflects
 * the value specified with that extension.
 *
 * @param locale the locale for which a display name for this currency is
 * needed
 * @return the symbol of this currency for the specified locale
 * @exception NullPointerException if <code>locale</code> is null
 */
 public String getSymbol(Locale locale) {
 LocaleServiceProviderPool pool =
 LocaleServiceProviderPool.getPool(CurrencyNameProvider.class);
 locale = CalendarDataUtility.findRegionOverride(locale);
 String symbol = pool.getLocalizedObject(
 CurrencyNameGetter.INSTANCE,
 locale, currencyCode, SYMBOL);
 if (symbol != null) {
 return symbol;
 }

 // use currency code as symbol of last resort
 return currencyCode;
 }

 /**
 * Gets the default number of fraction digits used with this currency.
 * Note that the number of fraction digits is the same as ISO 4217's
 * minor unit for the currency.
 * For example, the default number of fraction digits for the Euro is 2,
 * while for the Japanese Yen it's 0.
 * In the case of pseudo-currencies, such as IMF Special Drawing Rights,
 * -1 is returned.
 *
 * @return the default number of fraction digits used with this currency
 */
 public int getDefaultFractionDigits() {
 return defaultFractionDigits;
 }

 /**
 * Returns the ISO 4217 numeric code of this currency.
 *
 * @return the ISO 4217 numeric code of this currency
 * @since 1.7
 */
 public int getNumericCode() {
 return numericCode;
 }

 /**
 * Returns the 3 digit ISO 4217 numeric code of this currency as a {@code String}.
 * Unlike {@link #getNumericCode()}, which returns the numeric code as {@code int},
 * this method always returns the numeric code as a 3 digit string.
 * e.g. a numeric value of 32 would be returned as "032",
 * and a numeric value of 6 would be returned as "006".
 *
 * @return the 3 digit ISO 4217 numeric code of this currency as a {@code String}
 * @since 9
 */
 public String getNumericCodeAsString() {
 /* numeric code could be returned as a 3 digit string simply by using
 String.format("%03d",numericCode); which uses regex to parse the format,
 "%03d" in this case. Parsing a regex gives an extra performance overhead,
 so String.format() approach is avoided in this scenario.
 */
 if (numericCode < 100) {
 StringBuilder sb = new StringBuilder();
 sb.append('0');
 if (numericCode < 10) {
 sb.append('0');
 }
 return sb.append(numericCode).toString();
 }
 return String.valueOf(numericCode);
 }

 /**
 * Gets the name that is suitable for displaying this currency for
 * the default {@link Locale.Category#DISPLAY DISPLAY} locale.
 * If there is no suitable display name found
 * for the default locale, the ISO 4217 currency code is returned.
 * <p>
 * This is equivalent to calling
 * {@link #getDisplayName(Locale)
 * getDisplayName(Locale.getDefault(Locale.Category.DISPLAY))}.
 *
 * @return the display name of this currency for the default
 * {@link Locale.Category#DISPLAY DISPLAY} locale
 * @since 1.7
 */
 public String getDisplayName() {
 return getDisplayName(Locale.getDefault(Locale.Category.DISPLAY));
 }

 /**
 * Gets the name that is suitable for displaying this currency for
 * the specified locale. If there is no suitable display name found
 * for the specified locale, the ISO 4217 currency code is returned.
 *
 * @param locale the locale for which a display name for this currency is
 * needed
 * @return the display name of this currency for the specified locale
 * @exception NullPointerException if <code>locale</code> is null
 * @since 1.7
 */
 public String getDisplayName(Locale locale) {
 LocaleServiceProviderPool pool =
 LocaleServiceProviderPool.getPool(CurrencyNameProvider.class);
 String result = pool.getLocalizedObject(
 CurrencyNameGetter.INSTANCE,
 locale, currencyCode, DISPLAYNAME);
 if (result != null) {
 return result;
 }

 // use currency code as symbol of last resort
 return currencyCode;
 }

 /**
 * Returns the ISO 4217 currency code of this currency.
 *
 * @return the ISO 4217 currency code of this currency
 */
 @Override
 public String toString() {
 return currencyCode;
 }

 /**
 * Resolves instances being deserialized to a single instance per currency.
 */
 private Object readResolve() {
 return getInstance(currencyCode);
 }

 /**
 * Gets the main table entry for the country whose country code consists
 * of char1 and char2.
 */
 private static int getMainTableEntry(char char1, char char2) {
 if (char1 < 'A' || char1 > 'Z' || char2 < 'A' || char2 > 'Z') {
 throw new IllegalArgumentException();
 }
 return mainTable[(char1 - 'A') * A_TO_Z + (char2 - 'A')];
 }

 /**
 * Sets the main table entry for the country whose country code consists
 * of char1 and char2.
 */
 private static void setMainTableEntry(char char1, char char2, int entry) {
 if (char1 < 'A' || char1 > 'Z' || char2 < 'A' || char2 > 'Z') {
 throw new IllegalArgumentException();
 }
 mainTable[(char1 - 'A') * A_TO_Z + (char2 - 'A')] = entry;
 }

 /**
 * Obtains a localized currency names from a CurrencyNameProvider
 * implementation.
 */
 private static class CurrencyNameGetter
 implements LocaleServiceProviderPool.LocalizedObjectGetter<CurrencyNameProvider,
 String> {
 private static final CurrencyNameGetter INSTANCE = new CurrencyNameGetter();

 @Override
 public String getObject(CurrencyNameProvider currencyNameProvider,
 Locale locale,
 String key,
 Object... params) {
 assert params.length == 1;
 int type = (Integer)params[0];

 switch(type) {
 case SYMBOL:
 return currencyNameProvider.getSymbol(key, locale);
 case DISPLAYNAME:
 return currencyNameProvider.getDisplayName(key, locale);
 default:
 assert false; // shouldn't happen
 }

 return null;
 }
 }

 private static int[] readIntArray(DataInputStream dis, int count) throws IOException {
 int[] ret = new int[count];
 for (int i = 0; i < count; i++) {
 ret[i] = dis.readInt();
 }

 return ret;
 }

 private static List<SpecialCaseEntry> readSpecialCases(DataInputStream dis,
 int count)
 throws IOException {

 List<SpecialCaseEntry> list = new ArrayList<>(count);
 long cutOverTime;
 String oldCurrency;
 String newCurrency;
 int oldCurrencyFraction;
 int newCurrencyFraction;
 int oldCurrencyNumericCode;
 int newCurrencyNumericCode;

 for (int i = 0; i < count; i++) {
 cutOverTime = dis.readLong();
 oldCurrency = dis.readUTF();
 newCurrency = dis.readUTF();
 oldCurrencyFraction = dis.readInt();
 newCurrencyFraction = dis.readInt();
 oldCurrencyNumericCode = dis.readInt();
 newCurrencyNumericCode = dis.readInt();
 SpecialCaseEntry sc = new SpecialCaseEntry(cutOverTime,
 oldCurrency, newCurrency,
 oldCurrencyFraction, newCurrencyFraction,
 oldCurrencyNumericCode, newCurrencyNumericCode);
 list.add(sc);
 }
 return list;
 }

 private static List<OtherCurrencyEntry> readOtherCurrencies(DataInputStream dis,
 int count)
 throws IOException {

 List<OtherCurrencyEntry> list = new ArrayList<>(count);
 String currencyCode;
 int fraction;
 int numericCode;

 for (int i = 0; i < count; i++) {
 currencyCode = dis.readUTF();
 fraction = dis.readInt();
 numericCode = dis.readInt();
 OtherCurrencyEntry oc = new OtherCurrencyEntry(currencyCode,
 fraction,
 numericCode);
 list.add(oc);
 }
 return list;
 }

 /**
 * Parse currency data found in the properties file (that
 * java.util.currency.data designates) to a List of CurrencyProperty
 * instances. Also, remove invalid entries and the multiple currency
 * code inconsistencies.
 *
 * @param props properties containing currency data
 * @param pattern regex pattern for the properties entry
 * @return list of parsed property entries
 */
 private static List<CurrencyProperty> getValidCurrencyData(Properties props,
 Pattern pattern) {

 Set<String> keys = props.stringPropertyNames();
 List<CurrencyProperty> propertyEntries = new ArrayList<>();

 // remove all invalid entries and parse all valid currency properties
 // entries to a group of CurrencyProperty, classified by currency code
 Map<String, List<CurrencyProperty>> currencyCodeGroup = keys.stream()
 .map(k -> CurrencyProperty
 .getValidEntry(k.toUpperCase(Locale.ROOT),
 props.getProperty(k).toUpperCase(Locale.ROOT),
 pattern)).flatMap(o -> o.stream())
 .collect(Collectors.groupingBy(entry -> entry.currencyCode));

 // check each group for inconsistencies
 currencyCodeGroup.forEach((curCode, list) -> {
 boolean inconsistent = CurrencyProperty
 .containsInconsistentInstances(list);
 if (inconsistent) {
 list.forEach(prop -> CurrencyProperty.info("The property"
 + " entry for " + prop.country + " is inconsistent."
 + " Ignored.", null));
 } else {
 propertyEntries.addAll(list);
 }
 });

 return propertyEntries;
 }

 /**
 * Replaces currency data found in the properties file that
 * java.util.currency.data designates. This method is invoked for
 * each valid currency entry.
 *
 * @param prop CurrencyProperty instance of the valid property entry
 */
 private static void replaceCurrencyData(CurrencyProperty prop) {


 String ctry = prop.country;
 String code = prop.currencyCode;
 int numeric = prop.numericCode;
 int fraction = prop.fraction;
 int entry = numeric << NUMERIC_CODE_SHIFT;

 int index = SpecialCaseEntry.indexOf(code, fraction, numeric);


 // If a new entry changes the numeric code/dfd of an existing
 // currency code, update it in the sc list at the respective
 // index and also change it in the other currencies list and
 // main table (if that currency code is also used as a
 // simple case).

 // If all three components do not match with the new entry,
 // but the currency code exists in the special case list
 // update the sc entry with the new entry
 int scCurrencyCodeIndex = -1;
 if (index == -1) {
 scCurrencyCodeIndex = SpecialCaseEntry.currencyCodeIndex(code);
 if (scCurrencyCodeIndex != -1) {
 //currency code exists in sc list, then update the old entry
 specialCasesList.set(scCurrencyCodeIndex,
 new SpecialCaseEntry(code, fraction, numeric));

 // also update the entry in other currencies list
 OtherCurrencyEntry oe = OtherCurrencyEntry.findEntry(code);
 if (oe != null) {
 int oIndex = otherCurrenciesList.indexOf(oe);
 otherCurrenciesList.set(oIndex, new OtherCurrencyEntry(
 code, fraction, numeric));
 }
 }
 }

 /* If a country switches from simple case to special case or
 * one special case to other special case which is not present
 * in the sc arrays then insert the new entry in special case arrays.
 * If an entry with given currency code exists, update with the new
 * entry.
 */
 if (index == -1 && (ctry.charAt(0) != code.charAt(0)
 || ctry.charAt(1) != code.charAt(1))) {

 if(scCurrencyCodeIndex == -1) {
 specialCasesList.add(new SpecialCaseEntry(code, fraction,
 numeric));
 index = specialCasesList.size() - 1;
 } else {
 index = scCurrencyCodeIndex;
 }

 // update the entry in main table if it exists as a simple case
 updateMainTableEntry(code, fraction, numeric);
 }

 if (index == -1) {
 // simple case
 entry |= (fraction << SIMPLE_CASE_COUNTRY_DEFAULT_DIGITS_SHIFT)
 | (code.charAt(2) - 'A');
 } else {
 // special case
 entry = SPECIAL_CASE_COUNTRY_MASK
 | (index + SPECIAL_CASE_COUNTRY_INDEX_DELTA);
 }
 setMainTableEntry(ctry.charAt(0), ctry.charAt(1), entry);
 }

 // update the entry in maintable for any simple case found, if a new
 // entry as a special case updates the entry in sc list with
 // existing currency code
 private static void updateMainTableEntry(String code, int fraction,
 int numeric) {
 // checking the existence of currency code in mainTable
 int tableEntry = getMainTableEntry(code.charAt(0), code.charAt(1));
 int entry = numeric << NUMERIC_CODE_SHIFT;
 if ((tableEntry & COUNTRY_TYPE_MASK) == SIMPLE_CASE_COUNTRY_MASK
 && tableEntry != INVALID_COUNTRY_ENTRY
 && code.charAt(2) - 'A' == (tableEntry
 & SIMPLE_CASE_COUNTRY_FINAL_CHAR_MASK)) {

 int numericCode = (tableEntry & NUMERIC_CODE_MASK)
 >> NUMERIC_CODE_SHIFT;
 int defaultFractionDigits = (tableEntry
 & SIMPLE_CASE_COUNTRY_DEFAULT_DIGITS_MASK)
 >> SIMPLE_CASE_COUNTRY_DEFAULT_DIGITS_SHIFT;
 if (numeric != numericCode || fraction != defaultFractionDigits) {
 // update the entry in main table
 entry |= (fraction << SIMPLE_CASE_COUNTRY_DEFAULT_DIGITS_SHIFT)
 | (code.charAt(2) - 'A');
 setMainTableEntry(code.charAt(0), code.charAt(1), entry);
 }
 }
 }

 /* Used to represent a special case currency entry
 * - cutOverTime: cut-over time in millis as returned by
 * System.currentTimeMillis for special case countries that are changing
 * currencies; Long.MAX_VALUE for countries that are not changing currencies
 * - oldCurrency: old currencies for special case countries
 * - newCurrency: new currencies for special case countries that are
 * changing currencies; null for others
 * - oldCurrencyFraction: default fraction digits for old currencies
 * - newCurrencyFraction: default fraction digits for new currencies, 0 for
 * countries that are not changing currencies
 * - oldCurrencyNumericCode: numeric code for old currencies
 * - newCurrencyNumericCode: numeric code for new currencies, 0 for countries
 * that are not changing currencies
 */
 private static class SpecialCaseEntry {

 final private long cutOverTime;
 final private String oldCurrency;
 final private String newCurrency;
 final private int oldCurrencyFraction;
 final private int newCurrencyFraction;
 final private int oldCurrencyNumericCode;
 final private int newCurrencyNumericCode;

 private SpecialCaseEntry(long cutOverTime, String oldCurrency, String newCurrency,
 int oldCurrencyFraction, int newCurrencyFraction,
 int oldCurrencyNumericCode, int newCurrencyNumericCode) {
 this.cutOverTime = cutOverTime;
 this.oldCurrency = oldCurrency;
 this.newCurrency = newCurrency;
 this.oldCurrencyFraction = oldCurrencyFraction;
 this.newCurrencyFraction = newCurrencyFraction;
 this.oldCurrencyNumericCode = oldCurrencyNumericCode;
 this.newCurrencyNumericCode = newCurrencyNumericCode;
 }

 private SpecialCaseEntry(String currencyCode, int fraction,
 int numericCode) {
 this(Long.MAX_VALUE, currencyCode, "", fraction, 0, numericCode, 0);
 }

 //get the index of the special case entry
 private static int indexOf(String code, int fraction, int numeric) {
 int size = specialCasesList.size();
 for (int index = 0; index < size; index++) {
 SpecialCaseEntry scEntry = specialCasesList.get(index);
 if (scEntry.oldCurrency.equals(code)
 && scEntry.oldCurrencyFraction == fraction
 && scEntry.oldCurrencyNumericCode == numeric
 && scEntry.cutOverTime == Long.MAX_VALUE) {
 return index;
 }
 }
 return -1;
 }

 // get the fraction and numericCode of the sc currencycode
 private static int[] findEntry(String code) {
 int[] fractionAndNumericCode = null;
 int size = specialCasesList.size();
 for (int index = 0; index < size; index++) {
 SpecialCaseEntry scEntry = specialCasesList.get(index);
 if (scEntry.oldCurrency.equals(code) && (scEntry.cutOverTime == Long.MAX_VALUE
 || System.currentTimeMillis() < scEntry.cutOverTime)) {
 //consider only when there is no new currency or cutover time is not passed
 fractionAndNumericCode = new int[2];
 fractionAndNumericCode[0] = scEntry.oldCurrencyFraction;
 fractionAndNumericCode[1] = scEntry.oldCurrencyNumericCode;
 break;
 } else if (scEntry.newCurrency.equals(code)
 && System.currentTimeMillis() >= scEntry.cutOverTime) {
 //consider only if the cutover time is passed
 fractionAndNumericCode = new int[2];
 fractionAndNumericCode[0] = scEntry.newCurrencyFraction;
 fractionAndNumericCode[1] = scEntry.newCurrencyNumericCode;
 break;
 }
 }
 return fractionAndNumericCode;
 }

 // get the index based on currency code
 private static int currencyCodeIndex(String code) {
 int size = specialCasesList.size();
 for (int index = 0; index < size; index++) {
 SpecialCaseEntry scEntry = specialCasesList.get(index);
 if (scEntry.oldCurrency.equals(code) && (scEntry.cutOverTime == Long.MAX_VALUE
 || System.currentTimeMillis() < scEntry.cutOverTime)) {
 //consider only when there is no new currency or cutover time is not passed
 return index;
 } else if (scEntry.newCurrency.equals(code)
 && System.currentTimeMillis() >= scEntry.cutOverTime) {
 //consider only if the cutover time is passed
 return index;
 }
 }
 return -1;
 }


 // convert the special case entry to sc arrays index
 private static int toIndex(int tableEntry) {
 return (tableEntry & SPECIAL_CASE_COUNTRY_INDEX_MASK) - SPECIAL_CASE_COUNTRY_INDEX_DELTA;
 }

 }

 /* Used to represent Other currencies
 * - currencyCode: currency codes that are not the main currency
 * of a simple country
 * - otherCurrenciesDFD: decimal format digits for other currencies
 * - otherCurrenciesNumericCode: numeric code for other currencies
 */
 private static class OtherCurrencyEntry {

 final private String currencyCode;
 final private int fraction;
 final private int numericCode;

 private OtherCurrencyEntry(String currencyCode, int fraction,
 int numericCode) {
 this.currencyCode = currencyCode;
 this.fraction = fraction;
 this.numericCode = numericCode;
 }

 //get the instance of the other currency code
 private static OtherCurrencyEntry findEntry(String code) {
 int size = otherCurrenciesList.size();
 for (int index = 0; index < size; index++) {
 OtherCurrencyEntry ocEntry = otherCurrenciesList.get(index);
 if (ocEntry.currencyCode.equalsIgnoreCase(code)) {
 return ocEntry;
 }
 }
 return null;
 }

 }


 /*
 * Used to represent an entry of the properties file that
 * java.util.currency.data designates
 *
 * - country: country representing the currency entry
 * - currencyCode: currency code
 * - fraction: default fraction digit
 * - numericCode: numeric code
 * - date: cutover date
 */
 private static class CurrencyProperty {
 final private String country;
 final private String currencyCode;
 final private int fraction;
 final private int numericCode;
 final private String date;

 private CurrencyProperty(String country, String currencyCode,
 int fraction, int numericCode, String date) {
 this.country = country;
 this.currencyCode = currencyCode;
 this.fraction = fraction;
 this.numericCode = numericCode;
 this.date = date;
 }

 /**
 * Check the valid currency data and create/return an Optional instance
 * of CurrencyProperty
 *
 * @param ctry country representing the currency data
 * @param curData currency data of the given {@code ctry}
 * @param pattern regex pattern for the properties entry
 * @return Optional containing CurrencyProperty instance, If valid;
 * empty otherwise
 */
 private static Optional<CurrencyProperty> getValidEntry(String ctry,
 String curData,
 Pattern pattern) {

 CurrencyProperty prop = null;

 if (ctry.length() != 2) {
 // Invalid country code. Ignore the entry.
 } else {

 prop = parseProperty(ctry, curData, pattern);
 // if the property entry failed any of the below checked
 // criteria it is ignored
 if (prop == null
 || (prop.date == null && curData.chars()
 .map(c -> c == ',' ? 1 : 0).sum() >= 3)) {
 // format is not recognized. ignore the data if date
 // string is null and we've 4 values, bad date value
 prop = null;
 } else if (prop.fraction
 > SIMPLE_CASE_COUNTRY_MAX_DEFAULT_DIGITS) {
 prop = null;
 } else {
 try {
 if (prop.date != null
 && !isPastCutoverDate(prop.date)) {
 prop = null;
 }
 } catch (ParseException ex) {
 prop = null;
 }
 }
 }

 if (prop == null) {
 info("The property entry for " + ctry + " is invalid."
 + " Ignored.", null);
 }

 return Optional.ofNullable(prop);
 }

 /*
 * Parse properties entry and return CurrencyProperty instance
 */
 private static CurrencyProperty parseProperty(String ctry,
 String curData, Pattern pattern) {
 Matcher m = pattern.matcher(curData);
 if (!m.find()) {
 return null;
 } else {
 return new CurrencyProperty(ctry, m.group(1),
 Integer.parseInt(m.group(3)),
 Integer.parseInt(m.group(2)), m.group(4));
 }
 }

 /**
 * Checks if the given list contains multiple inconsistent currency instances
 */
 private static boolean containsInconsistentInstances(
 List<CurrencyProperty> list) {
 int numCode = list.get(0).numericCode;
 int fractionDigit = list.get(0).fraction;
 return list.stream().anyMatch(prop -> prop.numericCode != numCode
 || prop.fraction != fractionDigit);
 }

 private static boolean isPastCutoverDate(String s)
 throws ParseException {
 SimpleDateFormat format = new SimpleDateFormat(
 "yyyy-MM-dd'T'HH:mm:ss", Locale.ROOT);
 format.setTimeZone(TimeZone.getTimeZone("UTC"));
 format.setLenient(false);
 long time = format.parse(s.trim()).getTime();
 return System.currentTimeMillis() > time;

 }

 private static void info(String message, Throwable t) {
 PlatformLogger logger = PlatformLogger
 .getLogger("java.util.Currency");
 if (logger.isLoggable(PlatformLogger.Level.INFO)) {
 if (t != null) {
 logger.info(message, t);
 } else {
 logger.info(message);
 }
 }
 }

 }

}