/* Calls the DB2 stored procedure passing in the request string
            * as the first parameter and the metadata string as the second
            * parameter. If XMLRequestString contains a script or no output
            * metadata is required the xmlMetadata parameter may be null.
            * The outputMetadata boolean controls what is returned by the
            * method. If it is true any output metadata is returned. If
            * false the response output is returned. */
            private String callDB2StoredProc(String xmlRequestString,
            String xmlMetadataString,
            boolean outputMetadata)
            throws OCException,
            OCApiException
            {
            /* Create an SQL command to call the Stored procedure in DB2
            * to get the XML */
            String sql = "CALL db2info.MD_MESSAGE (?, ?, ?)";
            String response = null;
            String xmlMetadataResponse = null;
            CallableStatement callStmt = null;
            try
            {
            callStmt = auroraCatalogConnection.prepareCall(sql);
            /* Set input parameter to request and metadata strings. */
            callStmt.setString (1, xmlRequestString);
            callStmt.setString (2, xmlMetadataString);
            /* ReGISter the output parameters. */
            callStmt.registerOutParameter (2, Types.VARCHAR);
            callStmt.registerOutParameter (3, Types.VARCHAR);
            /* Call the stored procedure */
            callStmt.execute();
            /* Retrieve output parameters. If the procedure was called with
            * a request that returns metadata in the middle parameter then
            * xmlMetadataResponse will store the output XML. */
            if (outputMetadata == true)
            xmlMetadataResponse = callStmt.getString(2);
            response = callStmt.getString(3);
            /* See if there are any warnings. */
            SQLWarning warning = callStmt.getWarnings();
            /* If execute returns a warning with a non-zero SQL state
            * then the API has had an error and returned some response
            * info in the output XML document. */
            if (warning != null)
            {
            OCLog.trace("Stored procedure execute returned a warning.");
            OCLog.trace("SQL state: " + warning.getSQLState());
            OCLog.trace("SQL state: " + warning.getErrorCode());
            /* readResponseFromXML will throw an OCApiException containing
            * the error info (which will then be thrown to our caller) or
            * it will throw an OCException if a parsing error occurred. If
            * for some strange reason the file does not contain error
            * info it will just return and then we'll throw an OCException
            * to notify the user. */
            try { readResponseFromXML(response); }
            /* If an API exception was thrown add the SQL state etc to
            * it and then throw it again. */
            catch (OCApiException apie)
            {
            apie.setSqlException(warning);
            throw apie;
            }
            /* If we have had a warning we always want to rollback any changes.
            * If we have a problem rolling back the exception will be caught
            * below. */
            finally
            {
            auroraCatalogConnection.rollback();
            }
            /* If we got here there must have been a warning with nothing
            * in the output XML so throw an exception explaining this. */
            throw new OCException("OC_ERR_API_DB2_STORED_PROC_FAIL_NO_INFO");
            }
            }
            /* If we had an error executing the SQL, log the information and
            * throw an exception. We also rollback any changes and catch
            * the exception if the rollback has a problem. */
            catch (SQLException e)
            {
            OCApiException newe = new OCApiException(e);
            OCLog.trace( newe.getMessage() );
            logExceptionInfo(e);
            try { auroraCatalogConnection.rollback(); }
            catch (SQLException e2)
            {
            OCLog.trace("An exception also occurred rolling back.");
            logExceptionInfo(e2);
            }
            throw newe;
            }