ca.mcgill.cs.swevo.qualyzer.util.HibernateUtil.java Source code

Introduction

Here is the source code for ca.mcgill.cs.swevo.qualyzer.util.HibernateUtil.java

Source

/*******************************************************************************
 * Copyright (c) 2010 McGill University
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Barthelemy Dagenais (bart@cs.mcgill.ca)
 *******************************************************************************/
package ca.mcgill.cs.swevo.qualyzer.util;

import org.hibernate.HibernateException;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.Transaction;

import ca.mcgill.cs.swevo.qualyzer.model.HibernateDBManager;

/**
 * HibernateUtil provides utility methods to conveniently call the Hibernate API.
 * 
 * Most methods encapsulate thrown exceptions in a QualyzerException, log the exception, and perform cleanup actions if
 * necessary (e.g., rollback).
 * 
 * 
 */
public final class HibernateUtil {
    private HibernateUtil() {

    }

    /**
     * Close a session.
     * @param session
     */
    public static void quietClose(Session session) {
        if (session != null) {
            try {
                session.close();
            } catch (HibernateException e) {
                // logger.error("Error while closing a session.", e);
            }
        }
    }

    /**
     * Rollback a transaction.
     * @param transaction
     */
    public static void quietRollback(Transaction transaction) {
        if (transaction != null) {
            try {
                transaction.rollback();
            } catch (HibernateException e) {
                // logger.error("Error while rolling back a transaction.", e);
            }
        }
    }

    /**
     * Save an object.
     * @param manager
     * @param object
     */
    public static void quietSave(HibernateDBManager manager, Object object) {
        Transaction t = null;
        Session session = null;
        try {
            session = manager.openSession();
            t = session.beginTransaction();
            session.saveOrUpdate(object);
            session.flush();
            t.commit();
        } catch (HibernateException e) {
            quietRollback(t);
        } finally {
            quietClose(session);
        }
    }

    /**
     * Save many objects.
     * @param manager
     * @param objects
     */
    public static void quietSave(HibernateDBManager manager, Object[] objects) {
        Transaction t = null;
        Session session = null;
        try {
            session = manager.openSession();
            t = session.beginTransaction();
            for (Object object : objects) {
                session.saveOrUpdate(object);
            }
            session.flush();
            t.commit();
        } catch (HibernateException e) {
            quietRollback(t);
        } finally {
            quietClose(session);
        }
    }

    /**
     * Refresh an object.
     * @param manager
     * @param object
     */
    public static void quietRefresh(HibernateDBManager manager, Object object) {
        Transaction t = null;
        Session session = null;
        try {
            session = manager.openSession();
            t = session.beginTransaction();
            session.refresh(object);
            t.commit();
        } catch (HibernateException e) {
            quietRollback(t);
        } finally {
            quietClose(session);
        }
    }

    /**
     * Refresh many objects.
     * @param manager
     * @param objects
     */
    public static void quietRefresh(HibernateDBManager manager, Object[] objects) {
        Transaction t = null;
        Session session = null;
        try {
            session = manager.openSession();
            t = session.beginTransaction();
            for (Object object : objects) {
                session.refresh(object);
            }
            t.commit();
        } catch (HibernateException e) {
            quietRollback(t);
        } finally {
            quietClose(session);
        }
    }

    /**
     * 
     * Returns an int representing a count.
     * 
     * Pre-conditions:
     *   The query must be of form "select count(...) from ..."
     *   The session that created the query must be open
     *
     * @param query
     * @return
     */
    public static int count(Query query) {
        return ((Number) query.iterate().next()).intValue();
    }

}