/**
 *
 * Copyright 2003-2004 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.
 */

/*
 * Adapted from the Java Servlet API version 2.4 as available at
 *   http://search.maven.org/remotecontent?filepath=javax/servlet/servlet-api/2.4/servlet-api-2.4-sources.jar
 * Only relevant stubs of this file have been retained for test purposes.
 */

package javax.servlet;

import java.io.IOException;
import java.util.Enumeration;

/**
 *
 * Defines a generic, protocol-independent
 * servlet. To write an HTTP servlet for use on the
 * Web, extend {@link javax.servlet.http.HttpServlet} instead.
 *
 * <p><code>GenericServlet</code> implements the <code>Servlet</code>
 * and <code>ServletConfig</code> interfaces. <code>GenericServlet</code>
 * may be directly extended by a servlet, although it's more common to extend
 * a protocol-specific subclass such as <code>HttpServlet</code>.
 *
 * <p><code>GenericServlet</code> makes writing servlets
 * easier. It provides simple versions of the lifecycle methods
 * <code>init</code> and <code>destroy</code> and of the methods
 * in the <code>ServletConfig</code> interface. <code>GenericServlet</code>
 * also implements the <code>log</code> method, declared in the
 * <code>ServletContext</code> interface.
 *
 * <p>To write a generic servlet, you need only
 * override the abstract <code>service</code> method.
 *
 * @version $Rev: 46019 $ $Date: 2004-09-14 04:56:06 -0500 (Tue, 14 Sep 2004) $
 */
public abstract class GenericServlet implements Servlet, ServletConfig, java.io.Serializable {

    /**
     * Does nothing. All of the servlet initialization
     * is done by one of the <code>init</code> methods.
     */
    public GenericServlet() {
    }

    /**
     * Called by the servlet container to indicate to a servlet that the
     * servlet is being taken out of service.  See {@link Servlet#destroy}.
     */
    public void destroy() {
    }

    /**
     * Returns a <code>String</code> containing the value of the named
     * initialization parameter, or <code>null</code> if the parameter does
     * not exist.  See {@link ServletConfig#getInitParameter}.
     *
     * <p>This method is supplied for convenience. It gets the
     * value of the named parameter from the servlet's
     * <code>ServletConfig</code> object.
     *
     * @param name a <code>String</code> specifying the name
     * of the initialization parameter
     *
     * @return String a <code>String</code> containing the value
     * of the initalization parameter
     */
    public String getInitParameter(String name) {
        return null;
    }

    /**
     * Returns the names of the servlet's initialization parameters
     * as an <code>Enumeration</code> of <code>String</code> objects,
     * or an empty <code>Enumeration</code> if the servlet has no
     * initialization parameters.  See {@link
     * ServletConfig#getInitParameterNames}.
     *
     * <p>This method is supplied for convenience. It gets the
     * parameter names from the servlet's <code>ServletConfig</code> object.
     *
     *
     * @return Enumeration an enumeration of <code>String</code>
     * objects containing the names of the servlet's initialization parameters
     */
    public Enumeration getInitParameterNames() {
        return null;
    }

    /**
     * Returns this servlet's {@link ServletConfig} object.
     *
     * @return ServletConfig the <code>ServletConfig</code> object
     * that initialized this servlet
     */
    public ServletConfig getServletConfig() {
        return null;
    }


    /**
     * Returns a reference to the {@link ServletContext} in which this servlet
     * is running.  See {@link ServletConfig#getServletContext}.
     *
     * <p>This method is supplied for convenience. It gets the
     * context from the servlet's <code>ServletConfig</code> object.
     *
     *
     * @return ServletContext the <code>ServletContext</code> object
     * passed to this servlet by the <code>init</code> method
     */
    public ServletContext getServletContext() {
        return null;
    }


    /**
     * Returns information about the servlet, such as
     * author, version, and copyright.
     * By default, this method returns an empty string.  Override this method
     * to have it return a meaningful value.  See {@link
     * Servlet#getServletInfo}.
     *
     *
     * @return String information about this servlet, by default an
     * empty string
     */
    public String getServletInfo() {
        return null;
    }


    /**
     * Called by the servlet container to indicate to a servlet that the
     * servlet is being placed into service.  See {@link Servlet#init}.
     *
     * <p>This implementation stores the {@link ServletConfig}
     * object it receives from the servlet container for later use.
     * When overriding this form of the method, call
     * <code>super.init(config)</code>.
     *
     * @param config the <code>ServletConfig</code> object
     * that contains configutation information for this servlet
     *
     * @exception ServletException if an exception occurs that
     * interrupts the servlet's normal operation
     *
     * @see UnavailableException
     */
    public void init(ServletConfig config) throws ServletException {
    }


    /**
     * A convenience method which can be overridden so that there's no need
     * to call <code>super.init(config)</code>.
     *
     * <p>Instead of overriding {@link #init(ServletConfig)}, simply override
     * this method and it will be called by
     * <code>GenericServlet.init(ServletConfig config)</code>.
     * The <code>ServletConfig</code> object can still be retrieved via {@link
     * #getServletConfig}.
     *
     * @exception ServletException if an exception occurs that
     * interrupts the servlet's normal operation
     */
    public void init() throws ServletException {
    }


    /**
     * Called by the servlet container to allow the servlet to respond to
     * a request.  See {@link Servlet#service}.
     *
     * <p>This method is declared abstract so subclasses, such as
     * <code>HttpServlet</code>, must override it.
     *
     * @param req the <code>ServletRequest</code> object
     * that contains the client's request
     *
     * @param res the <code>ServletResponse</code> object
     * that will contain the servlet's response
     *
     * @exception ServletException if an exception occurs that
     * interferes with the servlet's normal operation occurred
     *
     * @exception IOException if an input or output
     * exception occurs
     */
    public abstract void service(ServletRequest req, ServletResponse res) throws ServletException, IOException;

    /**
     * Returns the name of this servlet instance.
     * See {@link ServletConfig#getServletName}.
     *
     * @return the name of this servlet instance
     */
    public String getServletName() {
        return null;
    }
}