public ConcurrentHClientPool(CassandraHost host) throws SQLException {
this.cassandraHost = host;
ds =
new CassandraDataSource(
cassandraHost.getHost(),
cassandraHost.getPort(),
cassandraHost.getKeyspaceName(),
cassandraHost.getUser(),
cassandraHost.getPassword());
availableConnectionQueue =
new ArrayBlockingQueue<CassandraConnectionHandle>(cassandraHost.getMaxActive(), true);
// This counter can be offset by as much as the number of threads.
activeConnectionCount = new AtomicInteger(0);
realActiveConnectionCount = new AtomicInteger(0);
numBlocked = new AtomicInteger();
active = new AtomicBoolean(true);
maxWaitTimeWhenExhausted =
cassandraHost.getMaxWaitTimeWhenExhausted() < 0
? 0
: cassandraHost.getMaxWaitTimeWhenExhausted();
for (int i = 0; i < cassandraHost.getMaxActive() / 3; i++) {
availableConnectionQueue.add(createConnection());
}
if (log.isDebugEnabled()) {
log.debug(
"Concurrent Host pool started with {} active clients; max: {} exhausted wait: {}",
new Object[] {getNumIdle(), cassandraHost.getMaxActive(), maxWaitTimeWhenExhausted});
}
}
@Override
public CassandraConnectionHandle borrowClient() throws SQLException {
if (!active.get()) {
throw new HPoolInnactiveException("Attempt to borrow on in-active pool: " + getName());
}
CassandraConnectionHandle conn = availableConnectionQueue.poll();
int currentActiveClients = activeConnectionCount.incrementAndGet();
try {
if (conn == null) {
if (currentActiveClients <= cassandraHost.getMaxActive()) {
conn = createConnection();
} else {
// We can't grow so let's wait for a connection to become available.
conn = waitForConnection();
}
}
if (conn == null) {
// Abnormal situation.
throw new HectorException(
"HConnectionManager returned a null client after aquisition - are we shutting down?");
}
} catch (RuntimeException e) {
activeConnectionCount.decrementAndGet();
throw e;
} catch (SQLException e) {
activeConnectionCount.decrementAndGet();
throw e;
}
realActiveConnectionCount.incrementAndGet();
return conn;
}
@Override
public int getMaxActive() {
return cassandraHost.getMaxActive();
}
@Override
public int getNumBeforeExhausted() {
return cassandraHost.getMaxActive() - realActiveConnectionCount.get();
}