001/* 002 * Copyright 2002-2012 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.web.bind.support; 018 019import org.springframework.web.context.request.WebRequest; 020 021/** 022 * Strategy interface for storing model attributes in a backend session. 023 * 024 * @author Juergen Hoeller 025 * @since 2.5 026 * @see org.springframework.web.bind.annotation.SessionAttributes 027 */ 028public interface SessionAttributeStore { 029 030 /** 031 * Store the supplied attribute in the backend session. 032 * <p>Can be called for new attributes as well as for existing attributes. 033 * In the latter case, this signals that the attribute value may have been modified. 034 * @param request the current request 035 * @param attributeName the name of the attribute 036 * @param attributeValue the attribute value to store 037 */ 038 void storeAttribute(WebRequest request, String attributeName, Object attributeValue); 039 040 /** 041 * Retrieve the specified attribute from the backend session. 042 * <p>This will typically be called with the expectation that the 043 * attribute is already present, with an exception to be thrown 044 * if this method returns {@code null}. 045 * @param request the current request 046 * @param attributeName the name of the attribute 047 * @return the current attribute value, or {@code null} if none 048 */ 049 Object retrieveAttribute(WebRequest request, String attributeName); 050 051 /** 052 * Clean up the specified attribute in the backend session. 053 * <p>Indicates that the attribute name will not be used anymore. 054 * @param request the current request 055 * @param attributeName the name of the attribute 056 */ 057 void cleanupAttribute(WebRequest request, String attributeName); 058 059}