code: private Split prepare() {
  		if (sql != null && !sql.equals("")) {
  			sqlNormalizer = new SqlNormalizer(sql);
  			sqlCmdLabel = prefix + ".sql." + sqlNormalizer.getType();
  			return startSplit();
  		} else {
  			return null;
  		}
  	}
docs: Called before each prepared SQL command execution. Prepares (obtains and starts)
  {@link org.javasimon.Stopwatch Stopwatch Simon} for measure SQL operation.
  
  @return Simon stopwatch object or null if sql is null or empty