private void checkAndInsert()

in server/mailet/mailets/src/main/java/org/apache/james/transport/mailets/WhiteListManager.java [298:374]
64 lines of code
15 McCabe index (conditional complexity)

    private void checkAndInsert(MailAddress senderMailAddress, Collection<MailAddress> recipients) throws MessagingException {
        String senderUser = senderMailAddress.getLocalPart().toLowerCase(Locale.US);
        Domain senderHost = senderMailAddress.getDomain();

        Connection conn = null;
        PreparedStatement selectStmt = null;
        PreparedStatement insertStmt = null;
        boolean dbUpdated = false;

        try {

            for (MailAddress recipient : recipients) {
                ResultSet selectRS = null;
                try {
                    String recipientUser = recipient.getLocalPart().toLowerCase(Locale.US);
                    Domain recipientHost = recipient.getDomain();

                    if (getMailetContext().isLocalServer(recipientHost)) {
                        // not a remote recipient, so skip
                        continue;
                    }

                    if (conn == null) {
                        conn = datasource.getConnection();
                    }

                    if (selectStmt == null) {
                        selectStmt = conn.prepareStatement(selectByPK);
                    }
                    selectStmt.setString(1, senderUser);
                    selectStmt.setString(2, senderHost.asString());
                    selectStmt.setString(3, recipientUser);
                    selectStmt.setString(4, recipientHost.asString());
                    selectRS = selectStmt.executeQuery();
                    if (selectRS.next()) {
                        // This address was already in the list
                        continue;
                    }

                    if (insertStmt == null) {
                        insertStmt = conn.prepareStatement(insert);
                    }
                    insertStmt.setString(1, senderUser);
                    insertStmt.setString(2, senderHost.asString());
                    insertStmt.setString(3, recipientUser);
                    insertStmt.setString(4, recipientHost.asString());
                    insertStmt.executeUpdate();
                    dbUpdated = true;

                } finally {
                    theJDBCUtil.closeJDBCResultSet(selectRS);
                }

                // Commit our changes if necessary.
                if (conn != null && dbUpdated && !conn.getAutoCommit()) {
                    conn.commit();
                    dbUpdated = false;
                }
            }
        } catch (SQLException sqle) {
            LOGGER.error("Error accessing database", sqle);
            throw new MessagingException("Exception thrown", sqle);
        } finally {
            theJDBCUtil.closeJDBCStatement(selectStmt);
            theJDBCUtil.closeJDBCStatement(insertStmt);
            // Rollback our changes if necessary.
            try {
                if (conn != null && dbUpdated && !conn.getAutoCommit()) {
                    conn.rollback();
                    dbUpdated = false;
                }
            } catch (Exception e) {
                LOGGER.error("Ignored exception upon rollback", e);
            }
            theJDBCUtil.closeJDBCConnection(conn);
        }
    }