src/main/java/de/uapcore/lightpit/dao/postgres/PGUserDao.java

/*
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 * Copyright 2018 Mike Becker. All rights reserved.
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 *      notice, this list of conditions and the following disclaimer.
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 *   2. Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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package de.uapcore.lightpit.dao.postgres;

import de.uapcore.lightpit.dao.UserDao;
import de.uapcore.lightpit.entities.User;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;

import static de.uapcore.lightpit.dao.Functions.setStringOrNull;

public final class PGUserDao implements UserDao {

    private final PreparedStatement insert, update, list, find;

    public PGUserDao(Connection connection) throws SQLException {
        list = connection.prepareStatement(
                "select userid, username, lastname, givenname, mail " +
                        "from lpit_user where userid >= 0 " +
                        "order by username");
        find = connection.prepareStatement(
                "select userid, username, lastname, givenname, mail " +
                        "from lpit_user where userid = ? ");

        insert = connection.prepareStatement("insert into lpit_user (username, lastname, givenname, mail) values (?, ?, ?, ?)");
        update = connection.prepareStatement("update lpit_user set lastname = ?, givenname = ?, mail = ? where userid = ?");
    }

    private User mapColumns(ResultSet result) throws SQLException {
        final int id = result.getInt("userid");
        if (id == 0) return null;
        final var user = new User(id);
        user.setUsername(result.getString("username"));
        user.setGivenname(result.getString("givenname"));
        user.setLastname(result.getString("lastname"));
        user.setMail(result.getString("mail"));
        return user;
    }

    @Override
    public void save(User instance) throws SQLException {
        Objects.requireNonNull(instance.getUsername());
        insert.setString(1, instance.getUsername());
        setStringOrNull(insert, 2, instance.getLastname());
        setStringOrNull(insert, 3, instance.getGivenname());
        setStringOrNull(insert, 4, instance.getMail());
        insert.executeUpdate();
    }

    @Override
    public boolean update(User instance) throws SQLException {
        if (instance.getId() < 0) return false;
        setStringOrNull(update, 1, instance.getLastname());
        setStringOrNull(update, 2, instance.getGivenname());
        setStringOrNull(update, 3, instance.getMail());
        update.setInt(4, instance.getId());
        return update.executeUpdate() > 0;
    }

    @Override
    public List<User> list() throws SQLException {
        List<User> users = new ArrayList<>();
        try (var result = list.executeQuery()) {
            while (result.next()) {
                users.add(mapColumns(result));
            }
        }
        return users;
    }

    @Override
    public User find(int id) throws SQLException {
        find.setInt(1, id);
        try (var result = find.executeQuery()) {
            if (result.next()) {
                return mapColumns(result);
            } else {
                return null;
            }
        }
    }
}