/*
 * $Header: /home/cvs/jakarta-tomcat/src/share/org/apache/jasper/servlet/ServletEngine.java,v 1.4 2004/02/23 06:30:55 billbarker Exp $
 * $Revision: 1.4 $
 * $Date: 2004/02/23 06:30:55 $
 *
 *
 *  Copyright 1999-2004 The Apache Software Foundation
 *
 *  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.apache.jasper.servlet;

import javax.servlet.ServletContext;

/**
 * Simple class to factor out servlet runner dependencies from the JSP
 * engine. There's a few motivations here: 
 *
 *	(a) ability for the JSP engine to be able to run on multiple
 *          servlet engines - 2.1 and 2.2
 *	(b) ability for the JSP engine to take advantage of specific
 *          servlet engines; this is crucial from a J2EE point of
 *          view. 
 *
 * @author Anil K. Vijendran
 * @author Harish Prabandham
 */
public class ServletEngine {
    static ServletEngine tomcat;
    static ServletEngine deflt;
    
    /**
     * Get a specific ServletEngine instance for the particular servlet runner
     * we are running on.
     */
    static ServletEngine getServletEngine(String serverInfo) {
        if (serverInfo.startsWith("Tomcat Web Server")) {
            if (tomcat == null) {
                try {
                    tomcat = (ServletEngine)
                        Class.forName("org.apache.jasper.runtime.TomcatServletEngine").newInstance();
                } catch (Exception ex) {
                    return null;
                }
            }
            return tomcat;
        } else {
            if (deflt == null) 
                deflt = new ServletEngine();
            return deflt;
        }
    }
    
    /**
     * Get the class loader for this ServletContext object. 
     */
    public ClassLoader getClassLoader(ServletContext ctx) {
        return null;
    }
}