001/* 002 * Copyright 2006-2012 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.batch.item.database.support; 018 019import org.springframework.util.StringUtils; 020 021/** 022 * HSQLDB implementation of a {@link org.springframework.batch.item.database.PagingQueryProvider} using database specific features. 023 * 024 * @author Thomas Risberg 025 * @author Michael Minella 026 * @since 2.0 027 */ 028public class HsqlPagingQueryProvider extends AbstractSqlPagingQueryProvider { 029 030 @Override 031 public String generateFirstPageQuery(int pageSize) { 032 return SqlPagingQueryUtils.generateTopSqlQuery(this, false, buildTopClause(pageSize)); 033 } 034 035 @Override 036 public String generateRemainingPagesQuery(int pageSize) { 037 if(StringUtils.hasText(getGroupClause())) { 038 return SqlPagingQueryUtils.generateGroupedTopSqlQuery(this, true, buildTopClause(pageSize)); 039 } 040 else { 041 return SqlPagingQueryUtils.generateTopSqlQuery(this, true, buildTopClause(pageSize)); 042 } 043 } 044 045 private String buildTopClause(int pageSize) { 046 return new StringBuilder().append("TOP ").append(pageSize).toString(); 047 } 048 049 @Override 050 public String generateJumpToItemQuery(int itemIndex, int pageSize) { 051 int page = itemIndex / pageSize; 052 int offset = (page * pageSize) - 1; 053 offset = offset<0 ? 0 : offset; 054 055 String topClause = new StringBuilder().append("LIMIT ").append(offset).append(" 1").toString(); 056 return SqlPagingQueryUtils.generateTopJumpToQuery(this, topClause); 057 } 058 059}