public class ClientInfoProvider {
    void enrichConnection(Connection connection, String userName)  throws SQLException  {
        OracleConnection oConn = (OracleConnection) connection;
            String[] metrics = new String[OracleConnection.END_TO_END_STATE_INDEX_MAX];
            metrics[OracleConnection.END_TO_END_CLIENTID_INDEX] = userName;
            oConn.setEndToEndMetrics(metrics, (short) 0);
    }
}

public class AuditableDataSource implements DataSource {
...
    @Override
    public Connection getConnection() throws SQLException {
        Connection connection = dataSource.getConnection();
        clientInfoProvider.enrichConnection(connection, userName);
        return connection;
    }
...
}