DBPortPool get(InetSocketAddress addr) {

      DBPortPool p = _pools.get(addr);

      if (p != null) return p;

      synchronized (_pools) {
        p = _pools.get(addr);
        if (p != null) {
          return p;
        }

        p = new DBPortPool(addr, _options);
        _pools.put(addr, p);
        String name = "com.mongodb:type=ConnectionPool,host=" + addr.toString().replace(':', '_');

        try {
          ObjectName on = new ObjectName(name);
          if (_server.isRegistered(on)) {
            _server.unregisterMBean(on);
            Bytes.LOGGER.log(
                Level.INFO, "multiple Mongo instances for same host, jmx numbers might be off");
          }
          _server.registerMBean(p, on);
        } catch (JMException e) {
          Bytes.LOGGER.log(Level.WARNING, "jmx registration error, continuing", e);
        } catch (java.security.AccessControlException e) {
          Bytes.LOGGER.log(Level.WARNING, "jmx registration error, continuing", e);
        }
      }

      return p;
    }
  void gotError(Exception e) {
    if (e instanceof java.nio.channels.ClosedByInterruptException
        || e instanceof InterruptedException) {
      // this is probably a request that is taking too long
      // so usually doesn't mean there is a real db problem
      return;
    }

    if (e instanceof java.net.SocketTimeoutException && _options.socketTimeout > 0) {
      // we don't want to clear the port pool for 1 connection timing out
      return;
    }

    // We don't want to clear the entire pool for the occasional error.
    if (e instanceof SocketException) {
      if (recentFailures < ALLOWED_ERRORS_BEFORE_CLEAR) {
        return;
      }
    }

    Bytes.LOGGER.log(Level.INFO, "emptying DBPortPool b/c of error", e);
    clear();
  }