Red Hat Web Application Framework 6.1 Bedienungsanleitung PDF herunterladen (Seite 105)

Chapter 9. Persistence Tutorial 91

9.7.2. Manual Transaction Management

When you manage your transactions locally, your starting point is the SessionManager class. From

there, you can get access to the Session class and then to the Transaction. Speciﬁcally, the Session

provides access to the TransactionContext, which has methods for beginning a transaction, committing

a transaction, and aborting a transaction. For example, the following code will open a transaction,

execute the necessary code and then either commit or abort the transaction:

import com.arsdigita.persistence.Session;

import com.arsdigita.persistence.SessionManager;

import com.arsdigita.persistence.TransactionContext;

Session session = SessionManager.getSession();

TransactionContext txn = session.getTransactionContext();

try {

txn.beginTxn();

// do some work here

txn.commitTxn();

} catch (Exception e) {

txn.abortTxn();

}

Transactions cannot be nested. If you have to make sure that you are in a transaction, use the inTxn()

method of TransactionContext, as in the following example:

import com.arsdigita.persistence.Session;

import com.arsdigita.persistence.SessionManager;

import com.arsdigita.persistence.TransactionContext;

Session session = SessionManager.getSession();

TransactionContext txn = session.getTransactionContext();

boolean openedTransaction = false;

try {

if (!txn.inTxn()) {

openedTransaction = true;

txn.beginTxn();

}

// do some work here

if (openedTransaction) {

txn.commitTxn();

}

} catch (Exception e) {

if (openedTransaction) {

txn.abortTxn();

}

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Red Hat Web Application Framework 6.1 Bedienungsanleitung Seite 105