1 | /* |
2 | * Copyright 2006-2012 the original author or authors. |
3 | * |
4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
5 | * you may not use this file except in compliance with the License. |
6 | * You may obtain a copy of the License at |
7 | * |
8 | * http://www.apache.org/licenses/LICENSE-2.0 |
9 | * |
10 | * Unless required by applicable law or agreed to in writing, software |
11 | * distributed under the License is distributed on an "AS IS" BASIS, |
12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
13 | * See the License for the specific language governing permissions and |
14 | * limitations under the License. |
15 | */ |
16 | |
17 | package org.springframework.batch.item.database.support; |
18 | |
19 | import org.springframework.util.StringUtils; |
20 | |
21 | /** |
22 | * HSQLDB implementation of a {@link org.springframework.batch.item.database.PagingQueryProvider} using database specific features. |
23 | * |
24 | * @author Thomas Risberg |
25 | * @author Michael Minella |
26 | * @since 2.0 |
27 | */ |
28 | public class HsqlPagingQueryProvider extends AbstractSqlPagingQueryProvider { |
29 | |
30 | @Override |
31 | public String generateFirstPageQuery(int pageSize) { |
32 | return SqlPagingQueryUtils.generateTopSqlQuery(this, false, buildTopClause(pageSize)); |
33 | } |
34 | |
35 | @Override |
36 | public String generateRemainingPagesQuery(int pageSize) { |
37 | if(StringUtils.hasText(getGroupClause())) { |
38 | return SqlPagingQueryUtils.generateGroupedTopSqlQuery(this, true, buildTopClause(pageSize)); |
39 | } |
40 | else { |
41 | return SqlPagingQueryUtils.generateTopSqlQuery(this, true, buildTopClause(pageSize)); |
42 | } |
43 | } |
44 | |
45 | private String buildTopClause(int pageSize) { |
46 | return new StringBuilder().append("TOP ").append(pageSize).toString(); |
47 | } |
48 | |
49 | @Override |
50 | public String generateJumpToItemQuery(int itemIndex, int pageSize) { |
51 | int page = itemIndex / pageSize; |
52 | int offset = (page * pageSize) - 1; |
53 | offset = offset<0 ? 0 : offset; |
54 | |
55 | String topClause = new StringBuilder().append("LIMIT ").append(offset).append(" 1").toString(); |
56 | return SqlPagingQueryUtils.generateTopJumpToQuery(this, topClause); |
57 | } |
58 | |
59 | } |