LightPIT: src/main/kotlin/de/uapcore/lightpit/dao/AbstractDao.kt@86b5d8a1662f

     1 /*

     2  * Copyright 2020 Mike Becker. All rights reserved.

     3  *

     4  * Redistribution and use in source and binary forms, with or without

     5  * modification, are permitted provided that the following conditions are met:

     6  *

     7  * 1. Redistributions of source code must retain the above copyright

     8  * notice, this list of conditions and the following disclaimer.

     9  *

    10  * 2. Redistributions in binary form must reproduce the above copyright

    11  * notice, this list of conditions and the following disclaimer in the

    12  * documentation and/or other materials provided with the distribution.

    13  *

    14  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

    15  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

    16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

    17  * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE

    18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

    19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR

    20  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER

    21  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,

    22  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

    23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

    24  *

    25  */

    27 package de.uapcore.lightpit.dao

    29 import java.sql.PreparedStatement

    30 import java.sql.ResultSet

    31 import java.sql.Types

    33 abstract class AbstractDao<T> {

    35     abstract fun mapResult(rs: ResultSet): T

    37     protected fun list(stmt: PreparedStatement): List<T> {

    38         return sequence {

    39             stmt.executeQuery().use { result ->

    40                 while (result.next()) yield(mapResult(result))

    41             }

    42         }.toList()

    43     }

    45     protected fun find(stmt: PreparedStatement): T? {

    46         stmt.executeQuery().use { result ->

    47             return if (result.next()) {

    48                 mapResult(result)

    49             } else {

    50                 null

    51             }

    52         }

    53     }

    55     // TODO: create PreparedStatement abstraction that provides some features

    57     // TODO: remove the following legacy code helper function

    58     protected fun <T> setForeignKeyOrNull(stmt: PreparedStatement, index: Int, instance: T?, keyGetter: (obj: T) -> Int) {

    59         if (instance == null) {

    60             stmt.setNull(index, Types.INTEGER)

    61         } else {

    62             stmt.setInt(index, keyGetter(instance))

    63         }

    64     }

    65 }

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