| 1 | /* |
| 2 | * Copyright 2007 brunella ltd |
| 3 | * |
| 4 | * Licensed under the LGPL Version 3 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * |
| 7 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
| 8 | * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 9 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 10 | * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
| 11 | * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| 12 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| 13 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| 14 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| 15 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 16 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF |
| 17 | * THE POSSIBILITY OF SUCH DAMAGE. |
| 18 | */ |
| 19 | package sf.qof.session; |
| 20 | |
| 21 | import java.sql.Connection; |
| 22 | import java.sql.SQLException; |
| 23 | import java.util.HashMap; |
| 24 | import java.util.Map; |
| 25 | |
| 26 | import javax.sql.DataSource; |
| 27 | |
| 28 | /** |
| 29 | * Implementation of a session context factory. |
| 30 | * |
| 31 | * <code>SessionContextFactory</code> provides factory methods to create and cache |
| 32 | * <code>SessionContext</code> objects. |
| 33 | * |
| 34 | * <p>The <code>SessionContextFactory</code> can be used in the following way:</p> |
| 35 | * |
| 36 | * <p><blockquote><pre> |
| 37 | * DataSource ds = ... // get the data source from somewhere |
| 38 | * // register the data source with the default session context |
| 39 | * SessionContextFactory.setDataSource(ds); |
| 40 | * ... |
| 41 | * // get the default session context |
| 42 | * SessionContext ctx = SessionContextFactory.getContext(); |
| 43 | * |
| 44 | * // start a new session |
| 45 | * ctx.startSession(); |
| 46 | * |
| 47 | * // start a new transaction |
| 48 | * ctx.getUserTransaction().begin(); |
| 49 | * |
| 50 | * // get the database connection for the current session |
| 51 | * Connection con = ctx.getConnection(); |
| 52 | * |
| 53 | * // do something with the connection |
| 54 | * ... |
| 55 | * |
| 56 | * // commit and end the current transaction |
| 57 | * ctx.getUserTransaction().commit(); |
| 58 | * |
| 59 | * // stop the session |
| 60 | * ctx.stopSession(); |
| 61 | * </pre></blockquote></p> |
| 62 | * |
| 63 | * @see sf.qof.session.SessionContext |
| 64 | * @see sf.qof.session.UserTransaction |
| 65 | * |
| 66 | */ |
| 67 | public class SessionContextFactory { |
| 68 | |
| 69 | private final static Map<String, SessionContext> sessionContextMap = new HashMap<String, SessionContext>(); |
| 70 | |
| 71 | private SessionContextFactory() { |
| 72 | } |
| 73 | |
| 74 | /** |
| 75 | * Creates and returns the default <code>SessionContext</code>. |
| 76 | * |
| 77 | * @return the session context |
| 78 | */ |
| 79 | public static SessionContext getContext() { |
| 80 | return getContext(SessionContext.DEFAULT_CONTEXT_NAME); |
| 81 | } |
| 82 | |
| 83 | /** |
| 84 | * Creates and returns the <code>SessionContext</code> for a given context name. |
| 85 | * |
| 86 | * @param contextName the context name |
| 87 | * @return the session context |
| 88 | */ |
| 89 | public synchronized static SessionContext getContext(String contextName) { |
| 90 | SessionContext sessionContext = sessionContextMap.get(contextName); |
| 91 | if (sessionContext == null) { |
| 92 | sessionContext = new DefaultSessionContext(contextName); |
| 93 | sessionContextMap.put(contextName, sessionContext); |
| 94 | } |
| 95 | return sessionContext; |
| 96 | } |
| 97 | |
| 98 | /** |
| 99 | * Registers a <code>DataSource</code> with the default session context. |
| 100 | * |
| 101 | * @param dataSource the data source |
| 102 | */ |
| 103 | public static void setDataSource(DataSource dataSource) { |
| 104 | setDataSource(SessionContext.DEFAULT_CONTEXT_NAME, dataSource); |
| 105 | } |
| 106 | |
| 107 | /** |
| 108 | * Registers a <code>DataSource</code> with the specified session context. |
| 109 | * |
| 110 | * @param contextName the session context name |
| 111 | * @param dataSource the data source |
| 112 | */ |
| 113 | public static void setDataSource(String contextName, DataSource dataSource) { |
| 114 | ((DefaultSessionContext) getContext(contextName)).setDataSource(dataSource); |
| 115 | } |
| 116 | |
| 117 | /** |
| 118 | * Internal implementation of <code>SessionContext</code>. |
| 119 | * |
| 120 | * Uses a <code>ThreadLocal</code> field to handle sessions for different threads. |
| 121 | * |
| 122 | */ |
| 123 | protected static class DefaultSessionContext implements SessionContext { |
| 124 | |
| 125 | private DataSource dataSource; |
| 126 | private String contextName; |
| 127 | |
| 128 | private ThreadLocal<Session> sessionThreadLocal = new ThreadLocal<Session>() { |
| 129 | protected synchronized Session initialValue() { |
| 130 | return new Session(); |
| 131 | } |
| 132 | }; |
| 133 | |
| 134 | private DefaultSessionContext(String contextName) { |
| 135 | this.contextName = contextName; |
| 136 | } |
| 137 | |
| 138 | private void setDataSource(DataSource dataSource) { |
| 139 | this.dataSource = dataSource; |
| 140 | } |
| 141 | |
| 142 | public Connection getConnection() { |
| 143 | Session session = sessionThreadLocal.get(); |
| 144 | if (session.getState() == SessionState.STOPPED) { |
| 145 | throw new IllegalStateException( |
| 146 | "Session is not running in thread for context " + contextName); |
| 147 | } else { |
| 148 | return session.getConnection(); |
| 149 | } |
| 150 | } |
| 151 | |
| 152 | public UserTransaction getUserTransaction() { |
| 153 | Session session = sessionThreadLocal.get(); |
| 154 | if (session.getState() == SessionState.STOPPED) { |
| 155 | throw new IllegalStateException( |
| 156 | "Session is not running in thread for context " + contextName); |
| 157 | } else { |
| 158 | return session.getUserTransaction(); |
| 159 | } |
| 160 | } |
| 161 | |
| 162 | public void startSession() throws SystemException { |
| 163 | Session session = sessionThreadLocal.get(); |
| 164 | if (session.getState() == SessionState.RUNNING) { |
| 165 | throw new IllegalStateException( |
| 166 | "Session already running in thread for context " + contextName); |
| 167 | } else { |
| 168 | if (dataSource == null) { |
| 169 | throw new SystemException("No data source defined for context " |
| 170 | + contextName); |
| 171 | } |
| 172 | Connection connection; |
| 173 | try { |
| 174 | connection = dataSource.getConnection(); |
| 175 | connection.setAutoCommit(false); |
| 176 | } catch (SQLException e) { |
| 177 | throw new SystemException(e); |
| 178 | } |
| 179 | session.setConnection(connection); |
| 180 | session.setUserTransaction(new DefaultUserTransaction(connection)); |
| 181 | session.setState(SessionState.RUNNING); |
| 182 | } |
| 183 | } |
| 184 | |
| 185 | public void stopSession() throws SystemException { |
| 186 | Session session = sessionThreadLocal.get(); |
| 187 | if (session.getState() == SessionState.STOPPED) { |
| 188 | throw new IllegalStateException( |
| 189 | "Session is not running in thread for context " + contextName); |
| 190 | } else { |
| 191 | session.setState(SessionState.STOPPED); |
| 192 | try { |
| 193 | ((DefaultUserTransaction) session.getUserTransaction()).close(); |
| 194 | session.setUserTransaction(null); |
| 195 | session.getConnection().close(); |
| 196 | session.setConnection(null); |
| 197 | } catch (SQLException e) { |
| 198 | throw new SystemException(e); |
| 199 | } |
| 200 | } |
| 201 | } |
| 202 | |
| 203 | |
| 204 | } |
| 205 | |
| 206 | private static class Session { |
| 207 | |
| 208 | private Connection connection; |
| 209 | private UserTransaction userTransaction; |
| 210 | private SessionState state = SessionState.STOPPED; |
| 211 | |
| 212 | public Connection getConnection() { |
| 213 | return connection; |
| 214 | } |
| 215 | |
| 216 | public void setConnection(Connection connection) { |
| 217 | this.connection = connection; |
| 218 | } |
| 219 | |
| 220 | public SessionState getState() { |
| 221 | return state; |
| 222 | } |
| 223 | |
| 224 | public void setState(SessionState state) { |
| 225 | this.state = state; |
| 226 | } |
| 227 | |
| 228 | public UserTransaction getUserTransaction() { |
| 229 | return userTransaction; |
| 230 | } |
| 231 | |
| 232 | public void setUserTransaction(UserTransaction userTransaction) { |
| 233 | this.userTransaction = userTransaction; |
| 234 | } |
| 235 | } |
| 236 | |
| 237 | private static enum SessionState { |
| 238 | STOPPED, RUNNING |
| 239 | } |
| 240 | |
| 241 | /** |
| 242 | * Internal implementation of <code>UserTransaction</code>. |
| 243 | * |
| 244 | */ |
| 245 | protected static class DefaultUserTransaction implements UserTransaction { |
| 246 | |
| 247 | private Connection connection; |
| 248 | |
| 249 | private TransactionState transactionState; |
| 250 | |
| 251 | /** |
| 252 | * Constructs a DefaultUserTransaction object. |
| 253 | * |
| 254 | * @param connection the current database connection |
| 255 | */ |
| 256 | public DefaultUserTransaction(Connection connection) { |
| 257 | this.connection = connection; |
| 258 | this.transactionState = TransactionState.NEW; |
| 259 | } |
| 260 | |
| 261 | public void begin() throws SystemException { |
| 262 | if (transactionState == TransactionState.NEW) { |
| 263 | transactionState = TransactionState.IN_TRANSACTION; |
| 264 | } else { |
| 265 | throw new IllegalStateException("Invalid state: Transaction is " + transactionState); |
| 266 | } |
| 267 | } |
| 268 | |
| 269 | public void commit() throws SystemException, RollbackException { |
| 270 | if (transactionState == TransactionState.NEW |
| 271 | || transactionState == TransactionState.CLOSED) { |
| 272 | throw new IllegalStateException("Invalid state: Transaction is " + transactionState); |
| 273 | } else { |
| 274 | if (transactionState == TransactionState.IN_TRANSACTION_ROLLBACK) { |
| 275 | transactionState = TransactionState.NEW; |
| 276 | try { |
| 277 | connection.rollback(); |
| 278 | } catch (SQLException e) { |
| 279 | throw new SystemException(e); |
| 280 | } |
| 281 | throw new RollbackException("Transaction was rolled back"); |
| 282 | } else { |
| 283 | transactionState = TransactionState.NEW; |
| 284 | try { |
| 285 | connection.commit(); |
| 286 | } catch (SQLException e) { |
| 287 | throw new SystemException(e); |
| 288 | } |
| 289 | } |
| 290 | } |
| 291 | } |
| 292 | |
| 293 | public boolean isRollbackOnly() { |
| 294 | if (transactionState == TransactionState.NEW |
| 295 | || transactionState == TransactionState.CLOSED) { |
| 296 | throw new IllegalStateException("Invalid state: Transaction is " + transactionState); |
| 297 | } else { |
| 298 | return transactionState == TransactionState.IN_TRANSACTION_ROLLBACK; |
| 299 | } |
| 300 | } |
| 301 | |
| 302 | public void rollback() throws SystemException { |
| 303 | if (transactionState == TransactionState.NEW |
| 304 | || transactionState == TransactionState.CLOSED) { |
| 305 | throw new IllegalStateException("Invalid state: Transaction is " + transactionState); |
| 306 | } else { |
| 307 | try { |
| 308 | transactionState = TransactionState.NEW; |
| 309 | connection.rollback(); |
| 310 | } catch (SQLException e) { |
| 311 | throw new SystemException(e); |
| 312 | } |
| 313 | } |
| 314 | } |
| 315 | |
| 316 | public void setRollbackOnly() throws SystemException { |
| 317 | if (transactionState == TransactionState.NEW |
| 318 | || transactionState == TransactionState.CLOSED) { |
| 319 | throw new IllegalStateException("Invalid state: Transaction is " + transactionState); |
| 320 | } else { |
| 321 | transactionState = TransactionState.IN_TRANSACTION_ROLLBACK; |
| 322 | } |
| 323 | } |
| 324 | |
| 325 | /** |
| 326 | * Closes the transaction. |
| 327 | */ |
| 328 | public void close() { |
| 329 | transactionState = TransactionState.CLOSED; |
| 330 | } |
| 331 | |
| 332 | private static enum TransactionState { |
| 333 | NEW, IN_TRANSACTION, IN_TRANSACTION_ROLLBACK, CLOSED |
| 334 | } |
| 335 | |
| 336 | } |
| 337 | } |