/*
* Copyright 2009-2016 Tilmann Zaeschke. All rights reserved.
*
* This file is part of ZooDB.
*
* ZooDB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* ZooDB 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with ZooDB. If not, see <http://www.gnu.org/licenses/>.
*
* See the README and COPYING files for further information.
*/
package org.zoodb;
import java.util.Collection;
import javax.jdo.PersistenceManager;
import org.zoodb.jdo.ZooJdoHelper;
import org.zoodb.tools.ZooHelper;
/**
* The main ZooDB rolling session class. Rolling sessions don't need to call {@code begin()}
* after {@code commit()} or {@code rollback()}. Instead there is always an open transaction.
* Note that while this can be very convenient, it may affect server performance in concurrent
* scenarios.
*
* @author ztilmann
* @deprecated Currently not supported, please use JDO instead
*/
public class ZooRollingSession {
//TODO: The concurrency aspect could be improved by internally starting the session when the
//first object is accessed or when the first API method is called, such as newQuery().
//private final Session tx;
private final PersistenceManager pm;
private ZooRollingSession(String dbName) {
pm = ZooJdoHelper.openDB(dbName);
pm.currentTransaction().begin();
}
/**
* Opens the database at the given location.
* The database is created if it does not exist.
* By default databases are created in %USER_HOME%/zoodb.
*
* @param dbName
* @return ZooRollingSession object
*/
static final ZooRollingSession open(String dbName) {
if (!ZooHelper.dbExists(dbName)) {
// create database
// By default, all database files will be created in %USER_HOME%/zoodb
ZooHelper.createDb(dbName);
}
return new ZooRollingSession(dbName);
}
public void commit() {
pm.currentTransaction().commit();
pm.currentTransaction().begin();
}
public void rollback() {
pm.currentTransaction().rollback();
pm.currentTransaction().begin();
}
public void makePersistent(Object pc) {
pm.makePersistent(pc);
}
public void delete(Object pc) {
pm.deletePersistent(pc);
}
public void close() {
if (pm.currentTransaction().isActive()) {
pm.currentTransaction().rollback();
}
pm.close();
pm.getPersistenceManagerFactory().close();
}
public Collection<?> query(String query) {
return (Collection<?>) pm.newQuery(query).execute();
}
}