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 java.util.Map; 020 021import org.springframework.batch.item.database.Order; 022 023/** 024 * Oracle implementation of a 025 * {@link org.springframework.batch.item.database.PagingQueryProvider} using 026 * database specific features. 027 * 028 * @author Thomas Risberg 029 * @author Michael Minella 030 * @since 2.0 031 */ 032public class OraclePagingQueryProvider extends AbstractSqlPagingQueryProvider { 033 034 @Override 035 public String generateFirstPageQuery(int pageSize) { 036 return SqlPagingQueryUtils.generateRowNumSqlQuery(this, false, buildRowNumClause(pageSize)); 037 } 038 039 @Override 040 public String generateRemainingPagesQuery(int pageSize) { 041 return SqlPagingQueryUtils.generateRowNumSqlQuery(this, true, buildRowNumClause(pageSize)); 042 } 043 044 @Override 045 public String generateJumpToItemQuery(int itemIndex, int pageSize) { 046 int page = itemIndex / pageSize; 047 int offset = (page * pageSize); 048 offset = offset == 0 ? 1 : offset; 049 String sortKeySelect = this.getSortKeySelect(); 050 return SqlPagingQueryUtils.generateRowNumSqlQueryWithNesting(this, sortKeySelect, sortKeySelect, false, "TMP_ROW_NUM = " 051 + offset); 052 } 053 054 private String getSortKeySelect() { 055 StringBuilder sql = new StringBuilder(); 056 String prefix = ""; 057 058 for (Map.Entry<String, Order> sortKey : this.getSortKeys().entrySet()) { 059 sql.append(prefix); 060 prefix = ", "; 061 sql.append(sortKey.getKey()); 062 } 063 064 return sql.toString(); 065 } 066 067 private String buildRowNumClause(int pageSize) { 068 return new StringBuilder().append("ROWNUM <= ").append(pageSize).toString(); 069 } 070 071}