DatabaseEngine

package database;

import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.logging.Level;
import java.util.logging.Logger;
import FileHandlers.Preferences;


public class DatabaseEngine {

    private Connection con;
    private ResultSet rs;
    Preferences pref = new Preferences();

    public void connect(String dbFile, String dbPass) {
        String url;
        try {
            Class.forName("net.ucanaccess.jdbc.UcanaccessDriver");
        } catch (ClassNotFoundException ex) {
            Logger.getLogger(DatabaseEngine.class.getName()).log(Level.SEVERE, null, ex);
        }
        try {
            con = DriverManager.getConnection("jdbc:ucanaccess://" + dbFile + ";jackcessOpener=database.CryptCodecOpener", "", dbPass);
        } catch (SQLException ex) {
            Logger.getLogger(DatabaseEngine.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    public PreparedStatement prepareStatement(String sql) {
        PreparedStatement stmt;
        connect(pref.getPreference("dbFileName"), pref.getPreference("dbPassword"));
        try {
            stmt = con.prepareStatement(sql, ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_UPDATABLE);
            return stmt;
        } catch (SQLException ex) {
            Logger.getLogger(DatabaseEngine.class.getName()).log(Level.SEVERE, null, ex);
        }
        return null;
    }

    public void execute(String sql) {
        Statement stmt;
        connect(pref.getPreference("dbFileName"), pref.getPreference("dbPassword"));
        try {
            stmt = con.createStatement();
            stmt.execute(sql);
            stmt.close();
        } catch (SQLException ex) {
            Logger.getLogger(DatabaseEngine.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    public void executeUpdate(PreparedStatement stmt) {
        try {
            stmt.executeUpdate();
        } catch (SQLException ex) {
            Logger.getLogger(DatabaseEngine.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    public ResultSet fetchResults(PreparedStatement stmt) {
        try {
            rs = stmt.executeQuery();
        } catch (SQLException ex) {
            Logger.getLogger(DatabaseEngine.class.getName()).log(Level.SEVERE, null, ex);
        }
        return rs;
    }

    public ResultSet getTableMetaData(String table) {
        connect(pref.getPreference("dbFileName"), pref.getPreference("dbPassword"));
        try {
            DatabaseMetaData meta = con.getMetaData();
            rs = meta.getTables(null, null, table, null);
        } catch (SQLException ex) {
            Logger.getLogger(DatabaseEngine.class.getName()).log(Level.SEVERE, null, ex);
        }
        return rs;
    }

    public boolean testConnection(String filename, String pass) {
        connect(filename, pass);
        try {
            Statement stmt = con.createStatement();
            stmt.executeQuery("SELECT * FROM events");
        } catch (SQLException ex) {
            Logger.getLogger(DatabaseEngine.class.getName()).log(Level.SEVERE, null, ex);
            return false;
        }
        return true;
    }

    public void closeConnection() {
        try {
            con.close();
            rs.close();
        } catch (SQLException ex) {
            Logger.getLogger(DatabaseEngine.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    public void closeConnection(PreparedStatement stmt) {
        try {
            stmt.close();
            con.close();
            rs.close();
        } catch (SQLException ex) {
            Logger.getLogger(DatabaseEngine.class.getName()).log(Level.SEVERE, null, ex);
        }
    }
}