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1 package org.hibernate.id;
3
4 import java.io.Serializable  ;
5 import java.sql.Connection ;
6 import java.sql.PreparedStatement ;
7 import java.sql.ResultSet ;
8 import java.sql.SQLException ;
9 import java.sql.Types ;
10 import java.util.Properties ;
11
12 import org.apache.commons.logging.Log;
13 import org.apache.commons.logging.LogFactory;
14 import org.hibernate.HibernateException;
15 import org.hibernate.LockMode;
16 import org.hibernate.dialect.Dialect;
17 import org.hibernate.engine.SessionImplementor;
18 import org.hibernate.engine.TransactionHelper;
19 import org.hibernate.mapping.Table;
20 import org.hibernate.type.Type;
21 import org.hibernate.util.PropertiesHelper;
22
23
44 public class TableGenerator extends TransactionHelper
45 implements PersistentIdentifierGenerator, Configurable {
46
47
48 public static final String COLUMN = "column";
49
50
51 public static final String DEFAULT_COLUMN_NAME = "next_hi";
52
53
54 public static final String TABLE = "table";
55
56
57 public static final String DEFAULT_TABLE_NAME = "hibernate_unique_key";
58
59 private static final Log log = LogFactory.getLog(TableGenerator.class);
60
61 private String tableName;
62 private String columnName;
63 private String query;
64 private String update;
65
66 public void configure(Type type, Properties params, Dialect dialect) {
67
68 this.tableName = PropertiesHelper.getString(TABLE, params, DEFAULT_TABLE_NAME);
69 this.columnName = PropertiesHelper.getString(COLUMN, params, DEFAULT_COLUMN_NAME);
70 String schemaName = params.getProperty(SCHEMA);
71 String catalogName = params.getProperty(CATALOG);
72
73 if (tableName.indexOf(dialect.getSchemaSeparator() )<0) {
74 tableName = Table.qualify( catalogName, schemaName, tableName, dialect.getSchemaSeparator() );
75 }
76
77 query = "select " +
78 columnName +
79 " from " +
80 dialect.appendLockHint(LockMode.UPGRADE, tableName) +
81 dialect.getForUpdateString();
82
83 update = "update " +
84 tableName +
85 " set " +
86 columnName +
87 " = ? where " +
88 columnName +
89 " = ?";
90 }
91
92 public synchronized Serializable generate(SessionImplementor session, Object object)
93 throws HibernateException {
94 int result = ( (Integer ) doWorkInNewTransaction(session) ).intValue();
95 return new Integer (result);
96 }
97
98
99 public String [] sqlCreateStrings(Dialect dialect) throws HibernateException {
100 return new String [] {
101 "create table " + tableName + " ( " + columnName + " " + dialect.getTypeName(Types.INTEGER) + " )",
102 "insert into " + tableName + " values ( 0 )"
103 };
104 }
105
106 public String [] sqlDropStrings(Dialect dialect) {
107 StringBuffer sqlDropString = new StringBuffer ()
109 .append("drop table ");
110 if ( dialect.supportsIfExistsBeforeTableName() ) sqlDropString.append("if exists ");
111 sqlDropString.append(tableName)
112 .append( dialect.getCascadeConstraintsString() );
113 if ( dialect.supportsIfExistsAfterTableName() ) sqlDropString.append(" if exists");
114 return new String [] { sqlDropString.toString() };
115 }
116
117 public Object generatorKey() {
118 return tableName;
119 }
120
121 public Serializable doWorkInCurrentTransaction(Connection conn, String sql) throws SQLException {
122 int result;
123 int rows;
124 do {
125
129 sql = query;
130 SQL.debug(query);
131 PreparedStatement qps = conn.prepareStatement(query);
132 try {
133 ResultSet rs = qps.executeQuery();
134 if ( !rs.next() ) {
135 String err = "could not read a hi value - you need to populate the table: " + tableName;
136 log.error(err);
137 throw new IdentifierGenerationException(err);
138 }
139 result = rs.getInt(1);
140 rs.close();
141 }
142 catch (SQLException sqle) {
143 log.error("could not read a hi value", sqle);
144 throw sqle;
145 }
146 finally {
147 qps.close();
148 }
149
150 sql = update;
151 SQL.debug(update);
152 PreparedStatement ups = conn.prepareStatement(update);
153 try {
154 ups.setInt( 1, result + 1 );
155 ups.setInt( 2, result );
156 rows = ups.executeUpdate();
157 }
158 catch (SQLException sqle) {
159 log.error("could not update hi value in: " + tableName, sqle);
160 throw sqle;
161 }
162 finally {
163 ups.close();
164 }
165 }
166 while (rows==0);
167 return new Integer (result);
168 }
169 }
170 |
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