static {
// if the property java.time.zone.DefaultZoneRulesProvider is
// set then its value is the class name of the default provider
final List<ZoneRulesProvider> loaded = new ArrayList<>();
AccessController.doPrivileged(
new PrivilegedAction<>() {
public Object run() {
String prop = System.getProperty("java.time.zone.DefaultZoneRulesProvider");
if (prop != null) {
try {
Class<?> c = Class.forName(prop, true, ClassLoader.getSystemClassLoader());
@SuppressWarnings("deprecation")
ZoneRulesProvider provider = ZoneRulesProvider.class.cast(c.newInstance());
registerProvider(provider);
loaded.add(provider);
} catch (Exception x) {
throw new Error(x);
}
} else {
registerProvider(new TzdbZoneRulesProvider());
}
return null;
}
});
ServiceLoader<ZoneRulesProvider> sl =
ServiceLoader.load(ZoneRulesProvider.class, ClassLoader.getSystemClassLoader());
Iterator<ZoneRulesProvider> it = sl.iterator();
while (it.hasNext()) {
ZoneRulesProvider provider;
try {
provider = it.next();
} catch (ServiceConfigurationError ex) {
if (ex.getCause() instanceof SecurityException) {
continue; // ignore the security exception, try the next provider
}
throw ex;
}
boolean found = false;
for (ZoneRulesProvider p : loaded) {
if (p.getClass() == provider.getClass()) {
found = true;
}
}
if (!found) {
registerProvider0(provider);
loaded.add(provider);
}
}
// CopyOnWriteList could be slow if lots of providers and each added individually
PROVIDERS.addAll(loaded);
}
/**
* Registers a zone rules provider.
*
* <p>This adds a new provider to those currently available. A provider supplies rules for one or
* more zone IDs. A provider cannot be registered if it supplies a zone ID that has already been
* registered. See the notes on time-zone IDs in {@link ZoneId}, especially the section on using
* the concept of a "group" to make IDs unique.
*
* <p>To ensure the integrity of time-zones already created, there is no way to deregister
* providers.
*
* @param provider the provider to register, not null
* @throws ZoneRulesException if a zone ID is already registered
*/
public static void registerProvider(ZoneRulesProvider provider) {
Objects.requireNonNull(provider, "provider");
registerProvider0(provider);
PROVIDERS.add(provider);
}
