code: private void readSourceDeclaration(LineNumberReader reader) throws IOException {
          String line;
          dataSourceProperties  = new Properties();
  
          while (!(line = reader.readLine()).isEmpty()) {
              int lineNumber = reader.getLineNumber();
              String[] tokens = line.split("[\t| ]+", 2);
  
              final String parameter = tokens[0].trim();
              final String inputParameter = tokens[1].trim();
  
              if (parameter.equals(Label.sourceUri.name())) {
                  dataSourceProperties.put(OntopSQLCoreSettings.JDBC_NAME, inputParameter);
              } else if (parameter.equals(Label.connectionUrl.name())) {
                  dataSourceProperties.put(OntopSQLCoreSettings.JDBC_URL, inputParameter);
              } else if (parameter.equals(Label.username.name())) {
                  dataSourceProperties.put(OntopSQLCredentialSettings.JDBC_USER, inputParameter);
              } else if (parameter.equals(Label.password.name())) {
                  dataSourceProperties.put(OntopSQLCredentialSettings.JDBC_PASSWORD, inputParameter);
              } else if (parameter.equals(Label.driverClass.name())) {
                  dataSourceProperties.put(OntopSQLCoreSettings.JDBC_DRIVER, inputParameter);
  
              } else {
                  String msg = String.format("Unknown parameter name \"%s\" at line: %d.", parameter, lineNumber);
                  throw new IOException(msg);
              }
          }
  
      }
docs: read and store datasource information