public void registerDataSource(String dataSourceName, DataSource dataSource) {
    dataSources.put(dataSourceName, dataSource);
    jdbcTemplates.put(dataSourceName, new NamedParameterJdbcTemplate(dataSource));
    transactionManagers.put(dataSourceName, new TransactionContextManager(new DataSourceTransactionManager(dataSource)));
  }
Adds an additional {@link DataSource} to this instance, specified by its name.

@param dataSourceName The name of the {@link DataSource} to add.
@param dataSource     The {@link DataSource} to add.
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/txn/jdbc/MultiDataSourceJdbcResource.java