org.openbp.server.persistence.hibernate.HibernatePersistenceContextProvider.java Source code

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Here is the source code for org.openbp.server.persistence.hibernate.HibernatePersistenceContextProvider.java

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/*
 *   Copyright 2007 skynamics AG
 *
 *   Licensed under the Apache License, Version 2.0 (the "License");
 *   you may not use this file except in compliance with the License.
 *   You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *   Unless required by applicable law or agreed to in writing, software
 *   distributed under the License is distributed on an "AS IS" BASIS,
 *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *   See the License for the specific language governing permissions and
 *   limitations under the License.
 */
package org.openbp.server.persistence.hibernate;

import java.util.Iterator;

import org.hibernate.HibernateException;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.hibernate.mapping.PersistentClass;
import org.openbp.server.context.TokenContextImpl;
import org.openbp.server.context.WorkflowTaskImpl;
import org.openbp.server.model.modelmgr.DbModel;
import org.openbp.server.model.modelmgr.DbModelItem;
import org.openbp.server.persistence.BasicPersistenceContextProvider;
import org.openbp.server.persistence.PersistenceContext;
import org.openbp.server.persistence.PersistenceException;

/**
 * Peristence context provider for a Hibernate-based persistence context.
 *
 * @author Heiko Erhardt
 */
public class HibernatePersistenceContextProvider extends BasicPersistenceContextProvider {
    //////////////////////////////////////////////////
    // @@ Private data
    //////////////////////////////////////////////////

    /** Session factory */
    protected transient SessionFactory sessionFactory;

    //////////////////////////////////////////////////
    // @@ Construction
    //////////////////////////////////////////////////

    /**
     * Constructor.
     */
    public HibernatePersistenceContextProvider() {
    }

    /**
     * @seem BasicPersistenceContextProvider.shutdown()
     */
    public void shutdown() {
        if (sessionFactory != null) {
            sessionFactory.close();
            sessionFactory = null;
        }
    }

    /**
     * Creates a new persistence context.
     *
     * @return The new context
     * @throws PersistenceException On error (e. g. if there is no database defined or a database session cannot be established)
     */
    protected PersistenceContext createPersistenceContext() throws PersistenceException {
        if (sessionFactory == null) {
            sessionFactory = createSessionFactory();
        }

        return new HibernatePersistenceContext(sessionFactory, this);
    }

    /**
     * Sets the session factory.
     * @nowarn
     */
    public void setSessionFactory(SessionFactory sessionFactory) {
        this.sessionFactory = sessionFactory;
    }

    //////////////////////////////////////////////////
    // @@ Session factory
    //////////////////////////////////////////////////

    /**
     * Creates a Hibernate session factory.
     *
     * @return The new factory or null
     * @throws PersistenceException On error (e. g. database/hibernate.properties missing or invalid)
     */
    protected SessionFactory createSessionFactory() throws PersistenceException {
        Configuration configuration = createHibernateConfiguration();

        try {
            // Create the session factory from the configuration
            return configuration.buildSessionFactory();
        } catch (HibernateException he) {
            throw new PersistenceException("Hibernate configuration problem:", he);
        }
    }

    /**
     * Creates a Hibernate configuration object that includes the OpenBP classes.
     * Adds the following class mappings (if not present yet):<br>
     * TokenContextImpl<br>
     * WorkflowTaskImpl<br>
     * DbModel<br>
     * DbModelItem
     *
     * @return The new configuration object
     */
    public Configuration createHibernateConfiguration() {
        // Prepare a configuration object for the session creation
        Configuration configuration = new Configuration();

        // Add the configuration in the hibernate.cfg.xml file
        configuration.configure();

        // Add the OpenBP core objects
        addOpenBPClassMappingsToConfiguration(configuration);

        return configuration;
    }

    /**
     * Adds class mappings for the OpenBP classes to the given Hibernate configuration object.
     * Adds the following class mappings (if not present yet):<br>
     * TokenContextImpl<br>
     * WorkflowTaskImpl<br>
     * DbModel<br>
     * DbModelItem
     *
     * @param configuration The configuration
     */
    public static void addOpenBPClassMappingsToConfiguration(Configuration configuration) {
        addClassMappingToConfiguration(configuration, TokenContextImpl.class);
        addClassMappingToConfiguration(configuration, WorkflowTaskImpl.class);
        addClassMappingToConfiguration(configuration, DbModel.class);
        addClassMappingToConfiguration(configuration, DbModelItem.class);
    }

    private static void addClassMappingToConfiguration(Configuration configuration, Class cls) {
        String className = cls.getName();
        for (Iterator it = configuration.getClassMappings(); it.hasNext();) {
            PersistentClass pc = (PersistentClass) it.next();
            if (pc.getClassName().equals(className)) {
                // Already mapped
                return;
            }
        }
        configuration.addClass(cls);
    }
}