/*
 * Copyright 2002-2012 the original author or authors.
 *
 * 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
 *
 *      https://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.springframework.web.servlet.handler;

import javax.servlet.Servlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.lang.Nullable;
import org.springframework.web.servlet.HandlerAdapter;
import org.springframework.web.servlet.ModelAndView;

Adapter to use the Servlet interface with the generic DispatcherServlet. Calls the Servlet's service method to handle a request. 
Last-modified checking is not explicitly supported: This is typically
handled by the Servlet implementation itself (usually deriving from
the HttpServlet base class).
This adapter is not activated by default; it needs to be defined as a
bean in the DispatcherServlet context. It will automatically apply to
mapped handler beans that implement the Servlet interface then.
Note that Servlet instances defined as bean will not receive initialization
and destruction callbacks, unless a special post-processor such as
SimpleServletPostProcessor is defined in the DispatcherServlet context.
Alternatively, consider wrapping a Servlet with Spring's
ServletWrappingController. This is particularly appropriate for
existing Servlet classes, allowing to specify Servlet initialization
parameters etc.
Author:
Juergen Hoeller
See Also:
Servlet
HttpServlet
SimpleServletPostProcessor
ServletWrappingController
Since:
1.1.5/**
 * Adapter to use the Servlet interface with the generic DispatcherServlet.
 * Calls the Servlet's {@code service} method to handle a request.
 *
 * <p>Last-modified checking is not explicitly supported: This is typically
 * handled by the Servlet implementation itself (usually deriving from
 * the HttpServlet base class).
 *
 * <p>This adapter is not activated by default; it needs to be defined as a
 * bean in the DispatcherServlet context. It will automatically apply to
 * mapped handler beans that implement the Servlet interface then.
 *
 * <p>Note that Servlet instances defined as bean will not receive initialization
 * and destruction callbacks, unless a special post-processor such as
 * SimpleServletPostProcessor is defined in the DispatcherServlet context.
 *
 * <p><b>Alternatively, consider wrapping a Servlet with Spring's
 * ServletWrappingController.</b> This is particularly appropriate for
 * existing Servlet classes, allowing to specify Servlet initialization
 * parameters etc.
 *
 * @author Juergen Hoeller
 * @since 1.1.5
 * @see javax.servlet.Servlet
 * @see javax.servlet.http.HttpServlet
 * @see SimpleServletPostProcessor
 * @see org.springframework.web.servlet.mvc.ServletWrappingController
 */
public class SimpleServletHandlerAdapter implements HandlerAdapter {

	@Override
	public boolean supports(Object handler) {
		return (handler instanceof Servlet);
	}

	@Override
	@Nullable
	public ModelAndView handle(HttpServletRequest request, HttpServletResponse response, Object handler)
			throws Exception {

		((Servlet) handler).service(request, response);
		return null;
	}

	@Override
	public long getLastModified(HttpServletRequest request, Object handler) {
		return -1;
	}

}