@Override
public WAL getWAL(final byte[] identifier) throws IOException {
final byte[] group = strategy.group(identifier);
WALProvider provider = cached.get(group);
if (null == provider) {
provider = populateCache(group);
}
return provider.getWAL(identifier);
}
/** Populate the cache for this group. */
WALProvider populateCache(final byte[] group) throws IOException {
final WALProvider temp =
factory.getProvider(
DELEGATE_PROVIDER,
DEFAULT_DELEGATE_PROVIDER,
listeners,
providerId + "-" + UUID.randomUUID());
final WALProvider extant = cached.putIfAbsent(group, temp);
if (null != extant) {
// someone else beat us to initializing, just take what they set.
temp.close();
return extant;
}
return temp;
}
@Override
public void close() throws IOException {
// save the last exception and rethrow
IOException failure = null;
for (WALProvider provider : cached.values()) {
try {
provider.close();
} catch (IOException exception) {
LOG.error("Problem closing provider '" + provider + "': " + exception.getMessage());
LOG.debug("Details of problem shutting down provider '" + provider + "'", exception);
failure = exception;
}
}
if (failure != null) {
throw failure;
}
}
