void switchConnectionIfRequired()

in wrapper/src/main/java/software/amazon/jdbc/plugin/readwritesplitting/ReadWriteSplittingPlugin.java [281:339]
52 lines of code
15 McCabe index (conditional complexity)

  void switchConnectionIfRequired(final boolean readOnly) throws SQLException {
    final Connection currentConnection = this.pluginService.getCurrentConnection();
    if (currentConnection != null && currentConnection.isClosed()) {
      logAndThrowException(Messages.get("ReadWriteSplittingPlugin.setReadOnlyOnClosedConnection"),
          SqlState.CONNECTION_NOT_OPEN);
    }

    if (isConnectionUsable(currentConnection)) {
      try {
        this.pluginService.refreshHostList();
      } catch (final SQLException e) {
        // ignore
      }
    }

    final List<HostSpec> hosts = this.pluginService.getHosts();
    if (Utils.isNullOrEmpty(hosts)) {
      logAndThrowException(Messages.get("ReadWriteSplittingPlugin.emptyHostList"));
    }

    final HostSpec currentHost = this.pluginService.getCurrentHostSpec();
    if (readOnly) {
      if (!pluginService.isInTransaction() && !isReader(currentHost)) {
        try {
          switchToReaderConnection(hosts);
        } catch (final SQLException e) {
          if (!isConnectionUsable(currentConnection)) {
            logAndThrowException(
                Messages.get("ReadWriteSplittingPlugin.errorSwitchingToReader", new Object[] { e.getMessage() }),
                SqlState.CONNECTION_UNABLE_TO_CONNECT,
                e);
            return;
          }

          // Failed to switch to a reader. {0}. The current writer will be used as a fallback: ''{1}''
          LOGGER.fine(() -> Messages.get(
              "ReadWriteSplittingPlugin.fallbackToWriter",
              new Object[] {
                  e.getMessage(),
                  this.pluginService.getCurrentHostSpec().getUrl()}));
        }
      }
    } else {
      if (!isWriter(currentHost) && pluginService.isInTransaction()) {
        logAndThrowException(
            Messages.get("ReadWriteSplittingPlugin.setReadOnlyFalseInTransaction"),
            SqlState.ACTIVE_SQL_TRANSACTION);
      }

      if (!isWriter(currentHost)) {
        try {
          switchToWriterConnection(hosts);
        } catch (final SQLException e) {
          logAndThrowException(Messages.get("ReadWriteSplittingPlugin.errorSwitchingToWriter"),
              SqlState.CONNECTION_UNABLE_TO_CONNECT, e);
        }
      }
    }
  }