/**
* Prepare the given Connection with the given transaction semantics.
*
* @param con the Connection to prepare
* @param definition the transaction definition to apply
* @return the previous isolation level, if any
* @throws SQLException if thrown by JDBC methods
* @see #resetConnectionAfterTransaction
*/
public static Integer prepareConnectionForTransaction(
Connection con, TransactionDefinition definition) throws SQLException {
Assert.notNull(con, "No Connection specified");
// Set read-only flag.
if (definition != null && definition.isReadOnly()) {
try {
if (logger.isDebugEnabled()) {
logger.debug("Setting JDBC Connection [" + con + "] read-only");
}
con.setReadOnly(true);
} catch (Throwable ex) {
// SQLException or UnsupportedOperationException
// -> ignore, it's just a hint anyway.
logger.debug("Could not set JDBC Connection read-only", ex);
}
}
// Apply specific isolation level, if any.
Integer previousIsolationLevel = null;
if (definition != null
&& definition.getIsolationLevel() != TransactionDefinition.ISOLATION_DEFAULT) {
if (logger.isDebugEnabled()) {
logger.debug(
"Changing isolation level of JDBC Connection ["
+ con
+ "] to "
+ definition.getIsolationLevel());
}
previousIsolationLevel = con.getTransactionIsolation();
con.setTransactionIsolation(definition.getIsolationLevel());
}
return previousIsolationLevel;
}
@Override
protected void doBegin(Object transaction, TransactionDefinition definition) {
JpaTransactionObject txObject = (JpaTransactionObject) transaction;
if (txObject.hasConnectionHolder()
&& !txObject.getConnectionHolder().isSynchronizedWithTransaction()) {
throw new IllegalTransactionStateException(
"Pre-bound JDBC Connection found! JpaTransactionManager does not support "
+ "running within DataSourceTransactionManager if told to manage the DataSource itself. "
+ "It is recommended to use a single JpaTransactionManager for all transactions "
+ "on a single DataSource, no matter whether JPA or JDBC access.");
}
try {
if (txObject.getEntityManagerHolder() == null
|| txObject.getEntityManagerHolder().isSynchronizedWithTransaction()) {
EntityManager newEm = createEntityManagerForTransaction();
if (logger.isDebugEnabled()) {
logger.debug("Opened new EntityManager [" + newEm + "] for JPA transaction");
}
txObject.setEntityManagerHolder(new EntityManagerHolder(newEm), true);
}
EntityManager em = txObject.getEntityManagerHolder().getEntityManager();
// Delegate to JpaDialect for actual transaction begin.
final int timeoutToUse = determineTimeout(definition);
Object transactionData =
getJpaDialect()
.beginTransaction(
em,
new DelegatingTransactionDefinition(definition) {
@Override
public int getTimeout() {
return timeoutToUse;
}
});
txObject.setTransactionData(transactionData);
// Register transaction timeout.
if (timeoutToUse != TransactionDefinition.TIMEOUT_DEFAULT) {
txObject.getEntityManagerHolder().setTimeoutInSeconds(timeoutToUse);
}
// Register the JPA EntityManager's JDBC Connection for the DataSource, if set.
if (getDataSource() != null) {
ConnectionHandle conHandle = getJpaDialect().getJdbcConnection(em, definition.isReadOnly());
if (conHandle != null) {
ConnectionHolder conHolder = new ConnectionHolder(conHandle);
if (timeoutToUse != TransactionDefinition.TIMEOUT_DEFAULT) {
conHolder.setTimeoutInSeconds(timeoutToUse);
}
if (logger.isDebugEnabled()) {
logger.debug(
"Exposing JPA transaction as JDBC transaction ["
+ conHolder.getConnectionHandle()
+ "]");
}
TransactionSynchronizationManager.bindResource(getDataSource(), conHolder);
txObject.setConnectionHolder(conHolder);
} else {
if (logger.isDebugEnabled()) {
logger.debug(
"Not exposing JPA transaction ["
+ em
+ "] as JDBC transaction because JpaDialect ["
+ getJpaDialect()
+ "] does not support JDBC Connection retrieval");
}
}
}
// Bind the entity manager holder to the thread.
if (txObject.isNewEntityManagerHolder()) {
TransactionSynchronizationManager.bindResource(
getEntityManagerFactory(), txObject.getEntityManagerHolder());
}
txObject.getEntityManagerHolder().setSynchronizedWithTransaction(true);
} catch (TransactionException ex) {
closeEntityManagerAfterFailedBegin(txObject);
throw ex;
} catch (Exception ex) {
closeEntityManagerAfterFailedBegin(txObject);
throw new CannotCreateTransactionException(
"Could not open JPA EntityManager for transaction", ex);
}
}