/*
 * Copyright 2005-2014 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
 *
 *      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.springframework.ws.transport.http;

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

import org.springframework.web.servlet.HandlerAdapter;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.ws.InvalidXmlException;
import org.springframework.ws.transport.WebServiceConnection;
import org.springframework.ws.transport.WebServiceMessageReceiver;
import org.springframework.ws.transport.support.WebServiceMessageReceiverObjectSupport;

/**
 * Adapter to use the {@link WebServiceMessageReceiver} interface with the generic {@link
 * org.springframework.web.servlet.DispatcherServlet}. Requires a {@link org.springframework.ws.WebServiceMessageFactory}
 * which is used to convert the incoming {@code HttpServletRequest} into a {@code WebServiceMessage}, and
 * passes that context to the mapped {@code WebServiceMessageReceiver}. If a response is created, that is sent via
 * the {@code HttpServletResponse}.
 *
 * <p>Note that the {@code MessageDispatcher} implements the {@code WebServiceMessageReceiver} interface,
 * enabling this adapter to function as a gateway to further message handling logic.
 *
 * @author Arjen Poutsma
 * @see #setMessageFactory(org.springframework.ws.WebServiceMessageFactory)
 * @see org.springframework.ws.transport.WebServiceMessageReceiver
 * @see org.springframework.ws.WebServiceMessageFactory
 * @see org.springframework.ws.server.MessageDispatcher
 * @since 1.0.0
 */
public class WebServiceMessageReceiverHandlerAdapter extends WebServiceMessageReceiverObjectSupport
		implements HandlerAdapter {

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

	@Override
	public ModelAndView handle(HttpServletRequest httpServletRequest,
							   HttpServletResponse httpServletResponse,
							   Object handler) throws Exception {
		if (HttpTransportConstants.METHOD_POST.equals(httpServletRequest.getMethod())) {
			WebServiceConnection connection = new HttpServletConnection(httpServletRequest, httpServletResponse);
			try {
				handleConnection(connection, (WebServiceMessageReceiver) handler);
			}
			catch (InvalidXmlException ex) {
				handleInvalidXmlException(httpServletRequest, httpServletResponse, handler, ex);
			}
		}
		else {
			handleNonPostMethod(httpServletRequest, httpServletResponse, handler);
		}
		return null;
	}

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

	/**
	 * Template method that is invoked when the request method is not {@code POST}. Called from {@link
	 * #handle(HttpServletRequest, HttpServletResponse, Object)}.
	 *
	 * <p>Default implementation set the response status to 405: Method Not Allowed. Can be overridden in subclasses.
	 *
	 * @param httpServletRequest  current HTTP request
	 * @param httpServletResponse current HTTP response
	 * @param handler			  current handler
	 */
	protected void handleNonPostMethod(HttpServletRequest httpServletRequest,
									   HttpServletResponse httpServletResponse,
									   Object handler) throws Exception {
		httpServletResponse.setStatus(HttpServletResponse.SC_METHOD_NOT_ALLOWED);
	}

	/**
	 * Template method that is invoked when parsing the request results in a {@link InvalidXmlException}. Called from
	 * {@link #handle(HttpServletRequest, HttpServletResponse, Object)}.
	 *
	 * <p>Default implementation set the response status to 400: Bad Request. Can be overridden in subclasses.
	 *
	 * @param httpServletRequest  current HTTP request
	 * @param httpServletResponse current HTTP response
	 * @param handler			  current handler
	 * @param ex				  the invalid XML exception that resulted in this method being called
	 */
	protected void handleInvalidXmlException(HttpServletRequest httpServletRequest,
											 HttpServletResponse httpServletResponse,
											 Object handler,
											 InvalidXmlException ex) throws Exception {
		httpServletResponse.setStatus(HttpServletResponse.SC_BAD_REQUEST);
	}

}