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.batch.item.database.PagingQueryProvider; 020import org.springframework.util.StringUtils; 021 022/** 023 * DB2 implementation of a {@link PagingQueryProvider} using 024 * database specific features. 025 * 026 * @author Thomas Risberg 027 * @author Michael Minella 028 * @since 2.0 029 */ 030public class Db2PagingQueryProvider extends SqlWindowingPagingQueryProvider { 031 032 @Override 033 public String generateFirstPageQuery(int pageSize) { 034 return SqlPagingQueryUtils.generateLimitSqlQuery(this, false, buildLimitClause(pageSize)); 035 } 036 037 @Override 038 public String generateRemainingPagesQuery(int pageSize) { 039 if(StringUtils.hasText(getGroupClause())) { 040 return SqlPagingQueryUtils.generateLimitGroupedSqlQuery(this, true, buildLimitClause(pageSize)); 041 } 042 else { 043 return SqlPagingQueryUtils.generateLimitSqlQuery(this, true, buildLimitClause(pageSize)); 044 } 045 } 046 047 @Override 048 protected Object getSubQueryAlias() { 049 return "AS TMP_SUB "; 050 } 051 052 private String buildLimitClause(int pageSize) { 053 return new StringBuilder().append("FETCH FIRST ").append(pageSize).append(" ROWS ONLY").toString(); 054 } 055 056}