/*
 * $Header: /cvsroot/mvnforum/myvietnam/src/net/myvietnam/mvncore/web/URLResolverFactory.java,v 1.6 2006/04/14 16:03:56 minhnn Exp $
 * $Author: minhnn $
 * $Revision: 1.6 $
 * $Date: 2006/04/14 16:03:56 $
 *
 * ====================================================================
 *
 * Copyright (C) 2002-2006 by MyVietnam.net
 *
 * All copyright notices regarding MyVietnam and MyVietnam CoreLib
 * MUST remain intact in the scripts and source code.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Correspondence and Marketing Questions can be sent to:
 * info at MyVietnam net
 *
 * @author: Minh Nguyen
 */
package net.myvietnam.mvncore.web;

import net.myvietnam.mvncore.MVNCoreConfig;
import net.myvietnam.mvncore.web.impl.URLResolverServletImpl;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class URLResolverFactory {

    private static Log log = LogFactory.getLog(URLResolverFactory.class);

    private static URLResolver urlResolver = null;

    /**
     * Private constructor to prevent instantiation
     */
    private URLResolverFactory() {
    }

    public static URLResolver getURLResolver() {

        if (urlResolver == null) {
            String urlResolverClassName = MVNCoreConfig.getURLResolverClassName();
            try {
                if (urlResolverClassName.length() > 0) {
                    Class urlResolverClass = Class.forName(urlResolverClassName);
                    urlResolver = (URLResolver) urlResolverClass.newInstance();
                }
            } catch (Throwable ex) {
                log.error("Cannot load URLResolver implementation (" + urlResolverClassName + ")", ex);
            }

            // fallback, now use the defualt implementation
            if (urlResolver == null) {
                urlResolver = new URLResolverServletImpl();
            }

            log.info("Using URLResolver = " + urlResolver);
        }

        return urlResolver;
    }
}