code: /*
   * Copyright (c) 2022 Airbyte, Inc., all rights reserved.
   */
  
  package io.airbyte.db.jdbc;
  
  import com.google.errorprone.annotations.MustBeClosed;
  import io.airbyte.commons.functional.CheckedConsumer;
  import io.airbyte.commons.functional.CheckedFunction;
  import io.airbyte.db.JdbcCompatibleSourceOperations;
  import java.sql.Connection;
  import java.sql.DatabaseMetaData;
  import java.sql.PreparedStatement;
  import java.sql.ResultSet;
  import java.sql.SQLException;
  import java.util.List;
  import java.util.stream.Collectors;
  import java.util.stream.Stream;
  import javax.sql.DataSource;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Database object for interacting with a JDBC connection. Can be used for any JDBC compliant db.
   */
  public class DefaultJdbcDatabase extends JdbcDatabase {
  
    private static final Logger LOGGER = LoggerFactory.getLogger(DefaultJdbcDatabase.class);
  
    protected final DataSource dataSource;
  
    public DefaultJdbcDatabase(final DataSource dataSource) {
      this(dataSource, JdbcUtils.getDefaultSourceOperations());
    }
  
    public DefaultJdbcDatabase(final DataSource dataSource, final JdbcCompatibleSourceOperations<?> sourceOperations) {
      super(sourceOperations);
      this.dataSource = dataSource;
    }
  
    @Override
    public void execute(final CheckedConsumer<Connection, SQLException> query) throws SQLException {
      try (final Connection connection = dataSource.getConnection()) {
        query.accept(connection);
      }
    }
  
    @Override
    public <T> List<T> bufferedResultSetQuery(final CheckedFunction<Connection, ResultSet, SQLException> query,
                                              final CheckedFunction<ResultSet, T, SQLException> recordTransform)
        throws SQLException {
      try (final Connection connection = dataSource.getConnection();
          final Stream<T> results = toUnsafeStream(query.apply(connection), recordTransform)) {
        return results.collect(Collectors.toList());
      }
    }
  
    @Override
    @MustBeClosed
    public <T> Stream<T> unsafeResultSetQuery(final CheckedFunction<Connection, ResultSet, SQLException> query,
                                              final CheckedFunction<ResultSet, T, SQLException> recordTransform)
        throws SQLException {
      final Connection connection = dataSource.getConnection();
      return toUnsafeStream(query.apply(connection), recordTransform)
          .onClose(() -> {
            try {
              connection.close();
            } catch (final SQLException e) {
              throw new RuntimeException(e);
            }
          });
    }
  
    @Override
    public DatabaseMetaData getMetaData() throws SQLException {
      final Connection conn = dataSource.getConnection();
      final DatabaseMetaData metaData = conn.getMetaData();
      conn.close();
      return metaData;
    }
  
    /**
     * You CANNOT assume that data will be returned from this method before the entire {@link ResultSet}
     * is buffered in memory. Review the implementation of the database's JDBC driver or use the
     * StreamingJdbcDriver if you need this guarantee. The caller should close the returned stream to
     * release the database connection.
     *
     * @param statementCreator create a {@link PreparedStatement} from a {@link Connection}.
     * @param recordTransform transform each record of that result set into the desired type. do NOT
     *        just pass the {@link ResultSet} through. it is a stateful object will not be accessible if
     *        returned from recordTransform.
     * @param <T> type that each record will be mapped to.
     * @return Result of the query mapped to a stream.
     * @throws SQLException SQL related exceptions.
     */
    @Override
    @MustBeClosed
    public <T> Stream<T> unsafeQuery(final CheckedFunction<Connection, PreparedStatement, SQLException> statementCreator,
                                     final CheckedFunction<ResultSet, T, SQLException> recordTransform)
        throws SQLException {
      final Connection connection = dataSource.getConnection();
      return toUnsafeStream(statementCreator.apply(connection).executeQuery(), recordTransform)
          .onClose(() -> {
            try {
              LOGGER.info("closing connection");
              connection.close();
            } catch (final SQLException e) {
              throw new RuntimeException(e);
            }
          });
    }
  
  }
  