src/main/java/dao/GroupDbDAO.java - dev6 - ihaverak/persons

src/main/java/dao/GroupDbDAO.java
114 строк4 KB
ihaverak
лаба 5
23 май 2026, 00:56
23 май 2026, 00:564bb74aa
package dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.LinkedList;
import java.util.List;
import domain.Group;
import exception.DAOException;

public class GroupDbDAO implements RepositoryDAO<Group> {

    private static final String SELECT_ALL = "SELECT id, groupname FROM groups ORDER BY groupname ASC";
    private static final String SELECT_BY_ID = "SELECT id, groupname FROM groups WHERE id = ?";
    private static final String INSERT = "INSERT INTO groups(groupname) VALUES(?)";
    private static final String EDIT = "UPDATE groups SET groupname = ? WHERE id = ?";
    private static final String DELETE = "DELETE FROM groups WHERE id = ?";

    private ConnectionBuilder builder = new DbConnectionBuilder();

    private Connection getConnection() throws SQLException {
        return builder.getConnection();
    }

    @Override
    public Long insert(Group group) throws DAOException {
        try (Connection con = getConnection();
             PreparedStatement pst = con.prepareStatement(INSERT, new String[]{"id"})) {
            Long id = -1L;
            pst.setString(1, group.getNameGroup());
            pst.executeUpdate();
            ResultSet gk = pst.getGeneratedKeys();
            if (gk.next()) {
                id = gk.getLong("id");
            }
            gk.close();
            return id;
        } catch (Exception e) {
            throw new DAOException(e);
        }
    }

    @Override
    public void update(Group group) throws DAOException {
        try (Connection con = getConnection();
             PreparedStatement pst = con.prepareStatement(EDIT)) {
            pst.setString(1, group.getNameGroup());
            pst.setLong(2, group.getId());
            pst.executeUpdate();
        } catch (Exception e) {
            throw new DAOException(e);
        }
    }

    @Override
    public void delete(Long id) throws DAOException {
        try (Connection con = getConnection();
             PreparedStatement pst = con.prepareStatement(DELETE)) {
            pst.setLong(1, id);
            pst.executeUpdate();
        } catch (Exception e) {
            throw new DAOException(e);
        }
    }

    @Override
    public Group findById(Long id) throws DAOException {
        Group group = null;
        try (Connection con = getConnection();
             PreparedStatement pst = con.prepareStatement(SELECT_BY_ID)) {
            pst.setLong(1, id);
            ResultSet rs = pst.executeQuery();
            if (rs.next()) {
                group = new Group();
                group.setId(rs.getLong("id"));
                group.setNameGroup(rs.getString("groupname"));
            }
            rs.close();
        } catch (Exception e) {
            throw new DAOException(e);
        }
        return group;
    }

    @Override
    public List<Group> findAll() throws DAOException {
        List<Group> list = new LinkedList<>();
        try (Connection con = getConnection();
             PreparedStatement pst = con.prepareStatement(SELECT_ALL);
             ResultSet rs = pst.executeQuery()) {
            while (rs.next()) {
                Group group = new Group();
                group.setId(rs.getLong("id"));
                group.setNameGroup(rs.getString("groupname"));
                list.add(group);
            }
        } catch (Exception e) {
            throw new DAOException(e);
        }
        return list;
    }

    public Group findById(Long id, List<Group> groups) {
        if (groups != null) {
            for (Group g : groups) {
                if (g.getId().equals(id)) {
                    return g;
                }
            }
        }
        return null;
    }
}