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8348351: Improve lazy initialization of the available currencies set #25134

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8348351: Improve lazy initialization of the available currencies set #25134

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f9e9c6b
init
justin-curtis-lu May 1, 2025
e2672ba
Chen's review - method name clarification
justin-curtis-lu May 8, 2025
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87 changes: 44 additions & 43 deletions src/java.base/share/classes/java/util/Currency.java
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Original file line number Diff line number Diff line change
Expand Up @@ -38,6 +38,7 @@
import java.time.format.DateTimeParseException;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.function.Supplier;
import java.util.regex.Pattern;
import java.util.regex.Matcher;
import java.util.spi.CurrencyNameProvider;
Expand Down Expand Up @@ -141,7 +142,8 @@ public final class Currency implements Serializable {
// class data: instance map

private static ConcurrentMap<String, Currency> instances = new ConcurrentHashMap<>(7);
private static HashSet<Currency> available;
private static final Supplier<HashSet<Currency>> available =
StableValue.supplier(Currency::computeAllCurrencies);

// Class data: currency data obtained from currency.data file.
// Purpose:
Expand Down Expand Up @@ -447,7 +449,7 @@ public static Currency getInstance(Locale locale) {
* @since 1.7
*/
public static Set<Currency> getAvailableCurrencies() {
return new HashSet<>(getCurrencies());
return new HashSet<>(available.get());
}

/**
Expand All @@ -462,53 +464,52 @@ public static Set<Currency> getAvailableCurrencies() {
* @since 25
*/
public static Stream<Currency> availableCurrencies() {
return getCurrencies().stream();
return available.get().stream();
}

// Returns the set of available Currencies which are lazily initialized
private static synchronized HashSet<Currency> getCurrencies() {
if (available == null) {
var sysTime = System.currentTimeMillis();
available = HashSet.newHashSet(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
|| sysTime < scEntry.cutOverTime) {
available.add(getInstance(scEntry.oldCurrency,
scEntry.oldCurrencyFraction,
scEntry.oldCurrencyNumericCode));
} else {
available.add(getInstance(scEntry.newCurrency,
scEntry.newCurrencyFraction,
scEntry.newCurrencyNumericCode));
}
// Builds and returns the set of available Currencies
private static HashSet<Currency> computeAllCurrencies() {
var sysTime = System.currentTimeMillis();
HashSet<Currency> available = HashSet.newHashSet(256);

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) {
// Simple Currencies
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) {
// Special Currencies
int index = SpecialCaseEntry.toIndex(tableEntry);
SpecialCaseEntry scEntry = specialCasesList.get(index);

if (scEntry.cutOverTime == Long.MAX_VALUE
|| sysTime < 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));
}
// Other Currencies
for (OtherCurrencyEntry entry : otherCurrenciesList) {
available.add(getInstance(entry.currencyCode));
}
return available;
}
Expand Down