https://github.com/spring-projects/spring-framework: Spring Web MVC (Spring IO)
  • Juergen Hoeller 
/*
 * Copyright 2002-2014 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
 *
 *      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;

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

import org.springframework.lang.Nullable;


A strategy interface for retrieving and saving FlashMap instances. See FlashMap for a general overview of flash attributes. 
Author:Rossen Stoyanchev
See Also:
Since:3.1
/**
 * A strategy interface for retrieving and saving FlashMap instances.
 * See {@link FlashMap} for a general overview of flash attributes.
 *
 * @author Rossen Stoyanchev
 * @since 3.1
 * @see FlashMap
 */
public interface FlashMapManager {

	
Find a FlashMap saved by a previous request that matches to the current
request, remove it from underlying storage, and also remove other
expired FlashMap instances.

This method is invoked in the beginning of every request in contrast to saveOutputFlashMap, which is invoked only when there are flash attributes to be saved - i.e. before a redirect. 
Params:
  • request – the current request
  • response – the current response
Returns:a FlashMap matching the current request or null
/**
	 * Find a FlashMap saved by a previous request that matches to the current
	 * request, remove it from underlying storage, and also remove other
	 * expired FlashMap instances.
	 * <p>This method is invoked in the beginning of every request in contrast
	 * to {@link #saveOutputFlashMap}, which is invoked only when there are
	 * flash attributes to be saved - i.e. before a redirect.
	 * @param request the current request
	 * @param response the current response
	 * @return a FlashMap matching the current request or {@code null}
	 */
	@Nullable
	FlashMap retrieveAndUpdate(HttpServletRequest request, HttpServletResponse response);

	
Save the given FlashMap, in some underlying storage and set the start
of its expiration period.

NOTE: Invoke this method prior to a redirect in order
to allow saving the FlashMap in the HTTP session or in a response
cookie before the response is committed.

Params:
  • flashMap – the FlashMap to save
  • request – the current request
  • response – the current response
/**
	 * Save the given FlashMap, in some underlying storage and set the start
	 * of its expiration period.
	 * <p><strong>NOTE:</strong> Invoke this method prior to a redirect in order
	 * to allow saving the FlashMap in the HTTP session or in a response
	 * cookie before the response is committed.
	 * @param flashMap the FlashMap to save
	 * @param request the current request
	 * @param response the current response
	 */
	void saveOutputFlashMap(FlashMap flashMap, HttpServletRequest request, HttpServletResponse response);

}