Fri, 22 May 2020 16:21:59 +0200
some reformatting
1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 2018 Mike Becker. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 *
28 */
29 package de.uapcore.lightpit.dao;
31 import java.sql.SQLException;
33 public interface GenericDao<T> {
35 /**
36 * Finds an entity by its integer ID.
37 *
38 * @param id the id
39 * @return the enity or null if there is no such entity
40 * @throws SQLException on any kind of SQL errors
41 */
42 T find(int id) throws SQLException;
44 /**
45 * Inserts an instance into database.
46 *
47 * @param instance the instance to insert
48 * @throws SQLException on any kind of SQL errors
49 */
50 void save(T instance) throws SQLException;
52 /**
53 * Updates an instance in the database.
54 *
55 * @param instance the instance to insert
56 * @return true if an instance has been updated, false if no instance with the specified ID was found
57 * @throws SQLException on any kind of SQL errors
58 */
59 boolean update(T instance) throws SQLException;
61 /**
62 * Inserts or updates an instance in the database.
63 * Tries an update first and if that fails, performs a save.
64 *
65 * @param instance the instance to insert or update
66 * @throws SQLException on any kind of SQL errors
67 * @see #update(Object)
68 * @see #save(Object)
69 */
70 default void saveOrUpdate(T instance) throws SQLException {
71 if (!update(instance)) save(instance);
72 }
73 }