wicket-examples/src/java/wicket/examples/guestbook2/DBUtil.java

/*
 * $Id$
 * $Revision$
 * $Date$
 *
 * ====================================================================
 * 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 wicket.examples.guestbook2;

import net.sf.hibernate.HibernateException;
import net.sf.hibernate.Session;
import net.sf.hibernate.Transaction;
import net.sf.hibernate.cfg.Configuration;
import net.sf.hibernate.dialect.Dialect;
import net.sf.hibernate.impl.SessionFactoryImpl;


import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import wicket.examples.util.hibernate.ConfigException;
import wicket.examples.util.hibernate.HibernateHelper;

import java.io.IOException;

import java.net.URL;

import java.sql.Connection;
import java.sql.SQLException;
import java.sql.Statement;

import java.util.ArrayList;
import java.util.Date;
import java.util.List;

/**
 * Utility that sets up the database.
 */
public class DBUtil
{
    /** Log. */
    private static Log log = LogFactory.getLog(DBUtil.class);

    /** construct. */
    public DBUtil()
    {
        // no nada
    }

    /**
     * Initialize and create the database.
     * @throws ConfigException configuration error
     * @throws HibernateException hibernate error
     * @throws SQLException
     * @throws IOException
     */
    public void initDB(String configFile)
        throws HibernateException, ConfigException, IOException, SQLException
    {
        URL configUrl = DBUtil.class.getResource(configFile);

        HibernateHelper.setConfigURL(configUrl);
        HibernateHelper.init();

        Session session = HibernateHelper.getSession();
        Connection conn = session.connection();
        Statement stmt = conn.createStatement();
        boolean exists;

        try
        {
            stmt.executeQuery("select 1 from Comment");
            exists = true;
        }
        catch (SQLException e)
        {
            exists = false;
        }

        try
        {
            if ((!exists) || Boolean.getBoolean("createdb"))
            {
                SessionFactoryImpl sf = (SessionFactoryImpl) HibernateHelper
                    .getSessionFactory();
                Dialect dialect = sf.getDialect();
                Configuration config = HibernateHelper.getConfiguration();
                String[] drops = config.generateDropSchemaScript(dialect);
                String[] creates = config.generateSchemaCreationScript(dialect);

                execStmt(conn, stmt, splitAltTables(drops, true));
                execStmt(conn, stmt, splitAltTables(drops, false));
                execStmt(conn, stmt, creates);

                insertTestData(session);
            }
        }
        finally
        {
            HibernateHelper.closeSession();
        }
    }

    /**
     * Insert a couple of test cd's.
     * @param session hibernate session
     * @throws HibernateException
     */
    private void insertTestData(Session session)
        throws HibernateException
    {
        Transaction transaction = session.beginTransaction();

        Comment comment = new Comment();

        comment.setText("Hi this is my first comment");
        comment.setDate(new Date(System.currentTimeMillis() - 10000));

        session.save(comment);

        comment = new Comment();
        comment.setText("Hi this is my second comment");
        comment.setDate(new Date(System.currentTimeMillis() - 5000));

        session.save(comment);

        transaction.commit();
    }

    /**
     * Filter statements on start of statement.
     * @param drops statements
     * @param inclAlterFlag if true, everything that starts with alter, else the inverse
     * @return part of the input
     */
    private String[] splitAltTables(String[] drops, boolean inclAlterFlag)
    {
        List temp = new ArrayList();

        for (int i = 0; i < drops.length; i++)
        {
            if (inclAlterFlag)
            {
                if (drops[i].toLowerCase().trim().startsWith("alter"))
                {
                    temp.add(drops[i]);
                }
            }
            else
            {
                if (!drops[i].toLowerCase().trim().startsWith("alter"))
                {
                    temp.add(drops[i]);
                }
            }
        }

        return (String[]) temp.toArray(new String[temp.size()]);
    }

    /**
     * Execute statements.
     * @param conn connection
     * @param stmt statement object
     * @param stmts statements
     * @throws SQLException sql error
     */
    public void execStmt(Connection conn, Statement stmt, String[] stmts)
        throws SQLException
    {
        for (int i = 0; i < stmts.length; i++)
        {
            log.info("exec: " + stmts[i]);

            try
            {
                stmt.executeUpdate(stmts[i]);
                conn.commit();
            }
            catch (SQLException e)
            {
                log.error(e.getMessage());
            }
        }
    }
}