001/* 002 * Copyright 2002-2014 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.jdbc.support.incrementer; 018 019import javax.sql.DataSource; 020 021/** 022 * {@link DataFieldMaxValueIncrementer} that increments the maximum value of a given HSQL table 023 * with the equivalent of an auto-increment column. Note: If you use this class, your HSQL 024 * key column should <i>NOT</i> be auto-increment, as the sequence table does the job. 025 * 026 * <p>The sequence is kept in a table. There should be one sequence table per 027 * table that needs an auto-generated key. 028 * 029 * <p>Example: 030 * 031 * <pre class="code">create table tab (id int not null primary key, text varchar(100)); 032 * create table tab_sequence (value identity); 033 * insert into tab_sequence values(0);</pre> 034 * 035 * If "cacheSize" is set, the intermediate values are served without querying the 036 * database. If the server or your application is stopped or crashes or a transaction 037 * is rolled back, the unused values will never be served. The maximum hole size in 038 * numbering is consequently the value of cacheSize. 039 * 040 * <p><b>NOTE:</b> HSQL now supports sequences and you should consider using them instead: 041 * {@link HsqlSequenceMaxValueIncrementer} 042 * 043 * @author Jean-Pierre Pawlak 044 * @author Thomas Risberg 045 * @author Juergen Hoeller 046 * @see HsqlSequenceMaxValueIncrementer 047 */ 048public class HsqlMaxValueIncrementer extends AbstractIdentityColumnMaxValueIncrementer { 049 050 /** 051 * Default constructor for bean property style usage. 052 * @see #setDataSource 053 * @see #setIncrementerName 054 * @see #setColumnName 055 */ 056 public HsqlMaxValueIncrementer() { 057 } 058 059 /** 060 * Convenience constructor. 061 * @param dataSource the DataSource to use 062 * @param incrementerName the name of the sequence/table to use 063 * @param columnName the name of the column in the sequence table to use 064 */ 065 public HsqlMaxValueIncrementer(DataSource dataSource, String incrementerName, String columnName) { 066 super(dataSource, incrementerName, columnName); 067 } 068 069 070 @Override 071 protected String getIncrementStatement() { 072 return "insert into " + getIncrementerName() + " values(null)"; 073 } 074 075 @Override 076 protected String getIdentityStatement() { 077 return "select max(identity()) from " + getIncrementerName(); 078 } 079 080}