107 lines
3.0 KiB
Java
Executable File
107 lines
3.0 KiB
Java
Executable File
/*
|
|
* Copyright (C) 2001-2004 Red Hat Inc. All Rights Reserved.
|
|
*
|
|
* This library is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public License
|
|
* as published by the Free Software Foundation; either version 2.1 of
|
|
* the License, or (at your option) any later version.
|
|
*
|
|
* This library is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with this library; if not, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
*/
|
|
|
|
package com.arsdigita.london.util;
|
|
|
|
import com.arsdigita.persistence.SessionManager;
|
|
import com.arsdigita.persistence.TransactionContext;
|
|
|
|
|
|
/**
|
|
* <p>
|
|
* A class for safely running a piece of code within
|
|
* a dedicated database transaction. It ensures that
|
|
* if any exceptions are thrown, the transaction is
|
|
* safely aborted.
|
|
* </p>
|
|
* <p>
|
|
* Example usage is as follows:
|
|
* </p>
|
|
* <pre>
|
|
* Transaction txn = new Transaction() {
|
|
* protected void doRun() {
|
|
* ...do some stuff...
|
|
* }
|
|
* };
|
|
* txn.run();
|
|
* </pre>
|
|
* <p>
|
|
* This class implements the Runnable interface, so if
|
|
* this is intended to be used for a background
|
|
* thread, then instead of calling txn.run() the following
|
|
* code can be used:
|
|
* <pre>
|
|
* Thread thread = new Thread(new Transaction() {
|
|
* protected void doRun() {
|
|
* ...do some stuff...
|
|
* }
|
|
* });
|
|
* thread.start();
|
|
* </pre>
|
|
*
|
|
* @see com.arsdigita.persistence.SessionManager
|
|
* @see com.arsdigita.persistence.TransactionContext
|
|
*/
|
|
public abstract class Transaction implements Runnable {
|
|
|
|
private TransactionContext m_context;
|
|
|
|
/**
|
|
* Create a new transaction using the default persistence
|
|
* session.
|
|
*/
|
|
public Transaction() {
|
|
m_context = SessionManager.getSession().getTransactionContext();
|
|
}
|
|
|
|
/**
|
|
* Create a new transaction using the named persistence
|
|
* session. The named session must have been configured
|
|
* prior to creating this object
|
|
*
|
|
* @param session the name of the persistence session
|
|
*/
|
|
public Transaction(String session) {
|
|
m_context = SessionManager.getSession(session).getTransactionContext();
|
|
}
|
|
|
|
/**
|
|
* Starts a new transaction, invokes the doRun
|
|
* method and then commits / aborts the transaction
|
|
*/
|
|
public final void run() {
|
|
try {
|
|
m_context.beginTxn();
|
|
|
|
doRun();
|
|
|
|
m_context.commitTxn();
|
|
} finally {
|
|
if (m_context.inTxn()) {
|
|
m_context.abortTxn();
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Subclasses should implement this method to do whatever
|
|
* work they require.
|
|
*/
|
|
protected abstract void doRun();
|
|
}
|