universe@34: /*
universe@34:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
universe@34:  *
universe@34:  * Copyright 2018 Mike Becker. All rights reserved.
universe@34:  *
universe@34:  * Redistribution and use in source and binary forms, with or without
universe@34:  * modification, are permitted provided that the following conditions are met:
universe@34:  *
universe@34:  *   1. Redistributions of source code must retain the above copyright
universe@34:  *      notice, this list of conditions and the following disclaimer.
universe@34:  *
universe@34:  *   2. Redistributions in binary form must reproduce the above copyright
universe@34:  *      notice, this list of conditions and the following disclaimer in the
universe@34:  *      documentation and/or other materials provided with the distribution.
universe@34:  *
universe@34:  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
universe@34:  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
universe@34:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
universe@34:  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
universe@34:  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
universe@34:  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
universe@34:  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
universe@34:  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
universe@34:  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
universe@34:  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
universe@34:  * POSSIBILITY OF SUCH DAMAGE.
universe@34:  *
universe@34:  */
universe@34: package de.uapcore.lightpit.dao;
universe@34: 
universe@34: import java.sql.PreparedStatement;
universe@34: import java.sql.ResultSet;
universe@34: import java.sql.SQLException;
universe@38: import java.sql.Types;
universe@34: import java.util.ArrayList;
universe@34: import java.util.List;
universe@38: import java.util.Optional;
universe@38: import java.util.function.Function;
universe@34: 
universe@34: public abstract class AbstractDao<T> implements GenericDao<T> {
universe@34: 
universe@38:     private final PreparedStatement listQuery;
universe@34: 
universe@38:     protected AbstractDao(PreparedStatement listQuery) {
universe@38:         this.listQuery = listQuery;
universe@38:     }
universe@38: 
universe@38:     public final T mapColumns(ResultSet result) throws SQLException {
universe@38:         return mapColumns(result, "");
universe@38:     }
universe@38: 
universe@38:     public abstract T mapColumns(ResultSet result, String qualifier) throws SQLException;
universe@38: 
universe@38:     /**
universe@38:      * Qualifies a column label if an qualifier is specified.
universe@38:      *
universe@38:      * @param qualifier an optional qualifier
universe@38:      * @param label     the column label
universe@38:      * @return the label, qualified if necessary
universe@38:      */
universe@38:     protected final String qual(String qualifier, String label) {
universe@38:         if (qualifier == null || qualifier.isBlank()) {
universe@38:             return label;
universe@38:         } else {
universe@38:             return qualifier + "." + label;
universe@38:         }
universe@38:     }
universe@38: 
universe@38:     protected final void setStringOrNull(PreparedStatement stmt, int index, String str) throws SQLException {
universe@38:         if (str == null || str.isBlank()) {
universe@38:             stmt.setNull(index, Types.VARCHAR);
universe@38:         } else {
universe@38:             stmt.setString(index, str);
universe@38:         }
universe@38:     }
universe@38: 
universe@38:     protected final <T> void setForeignKeyOrNull(PreparedStatement stmt, int index, T instance, Function<T, Integer> keyGetter) throws SQLException {
universe@38:         Integer key = Optional.ofNullable(instance).map(keyGetter).orElse(null);
universe@38:         if (key == null) {
universe@38:             stmt.setNull(index, Types.INTEGER);
universe@38:         } else {
universe@38:             stmt.setInt(index, key);
universe@38:         }
universe@38:     }
universe@34: 
universe@34:     @Override
universe@38:     public List<T> list() throws SQLException {
universe@34:         List<T> list = new ArrayList<>();
universe@38:         try (ResultSet result = listQuery.executeQuery()) {
universe@34:             while (result.next()) {
universe@34:                 list.add(mapColumns(result));
universe@34:             }
universe@34:         }
universe@34:         return list;
universe@34:     }
universe@34: }