LightPIT: src/main/java/de/uapcore/lightpit/dao/GenericDao.java@edba952cfc57

     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      * It is not guaranteed that referenced entities are automatically joined.

    38      *

    39      * @param id the id

    40      * @return the enity or null if there is no such entity

    41      * @throws SQLException on any kind of SQL errors

    42      */

    43     T find(int id) throws SQLException;

    45     /**

    46      * Inserts an instance into database.

    47      * It is not guaranteed that generated fields will be updated in the instance.

    48      *

    49      * @param instance the instance to insert

    50      * @throws SQLException on any kind of SQL errors

    51      */

    52     void save(T instance) throws SQLException;

    54     /**

    55      * Updates an instance in the database.

    56      *

    57      * @param instance the instance to insert

    58      * @return true if an instance has been updated, false if no instance with the specified ID was found

    59      * @throws SQLException on any kind of SQL errors

    60      */

    61     boolean update(T instance) throws SQLException;

    63     /**

    64      * Inserts or updates an instance in the database.

    65      * Tries an update first and if that fails, performs a save.

    66      *

    67      * @param instance the instance to insert or update

    68      * @throws SQLException on any kind of SQL errors

    69      * @see #update(Object)

    70      * @see #save(Object)

    71      */

    72     default void saveOrUpdate(T instance) throws SQLException {

    73         if (!update(instance)) save(instance);

    74     }

    75 }

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