aswi2020vldc-gitlab/src/main/java/vldc/aswi/database/DatabaseInterface.java @ 2868bb9a

package vldc.aswi.database;

import org.springframework.context.annotation.Bean;
import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.ResultSetExtractor;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.stereotype.Component;
import vldc.aswi.model.table.TableColumn;

import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@Component
public class DatabaseInterface {

    private JdbcTemplate jdbcTemplate = null;

    public DatabaseInterface(JdbcTemplate jdbcTemplate) {
        this.jdbcTemplate = jdbcTemplate;
    }

    public Map<String, TableColumn> executeQueryAndReturnTableColumns(String sqlQuery) {
        return jdbcTemplate.query(
                sqlQuery,
                new ResultSetExtractor<Map<String, TableColumn>>() {
                    @Override
                    public Map<String, TableColumn> extractData(ResultSet resultSet) throws SQLException, DataAccessException {
                        List<TableColumn> tableColumnsList = new ArrayList<>();

                        ResultSetMetaData resultSetMetaData = resultSet.getMetaData();
                        int columnCount = resultSetMetaData.getColumnCount();

                        // The column count starts from 1.
                        for (int i = 1; i <= columnCount; i++ ) {
                            String columnName = resultSetMetaData.getColumnName(i);
                            tableColumnsList.add(new TableColumn(columnName));
                        }

                        while(resultSet.next()) {
                            for (int i = 1; i <= columnCount; i++) {
                                tableColumnsList.get(i - 1).addValue(resultSet.getString(i));
                            }
                        }

                        Map<String, TableColumn> tableColumnMap = new HashMap<>();

                        for (TableColumn column : tableColumnsList) {
                            tableColumnMap.put(column.getName(), column);
                        }

                        return tableColumnMap;
                    }
                }
        );
    }
}