src/main/java/de/uapcore/lightpit/dao/UserDao.java

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 * 
 * Copyright 2018 Mike Becker. All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   1. Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *
 *   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
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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package de.uapcore.lightpit.dao;

import de.uapcore.lightpit.entities.User;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
import java.util.Optional;

public class UserDao {

    /**
     * Maps SQL columns to POJO fields.
     *
     * @param result the database result set
     * @param user   the POJO
     * @throws SQLException
     */
    protected void mapColumns(ResultSet result, User user) throws SQLException {
        user.setUserID(result.getInt("userid"));
        user.setUsername(result.getString("username"));
        user.setGivenname(Optional.ofNullable(result.getString("givenname")));
        user.setLastname(Optional.ofNullable(result.getString("lastname"))); 
    }

    /**
     * Returns a list of all users ordered by their username.
     * 
     * Does not return reserved system users with negative user IDs.
     * 
     * @param conn the connection to use
     * @return a list of all users
     * @throws SQLException 
     */
    public List<User> listAll(Connection conn) throws SQLException {
        List<User> list = new ArrayList<>();
        try (
                Statement stmt = conn.createStatement();
                ResultSet result = stmt.executeQuery(
                        "SELECT * FROM lpitcore_user WHERE userid >= 0 ORDER BY username")) {
            while (result.next()) {
                final User user = new User();
                mapColumns(result, user);
                list.add(user);
            }
        }
        return list;
    }
}