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.portlet.handler; 018 019import javax.portlet.MimeResponse; 020import javax.portlet.PortletException; 021import javax.portlet.PortletRequest; 022import javax.portlet.PortletResponse; 023 024import org.springframework.web.portlet.context.PortletApplicationObjectSupport; 025 026/** 027 * Convenient superclass for any kind of web content generator, 028 * like {@link org.springframework.web.portlet.mvc.AbstractController}. 029 * Can also be used for custom handlers that have their own 030 * {@link org.springframework.web.portlet.HandlerAdapter}. 031 * 032 * <p>Supports portlet cache control options. 033 * 034 * @author Juergen Hoeller 035 * @author John A. Lewis 036 * @since 2.0 037 * @see #setCacheSeconds 038 * @see #setRequireSession 039 */ 040public abstract class PortletContentGenerator extends PortletApplicationObjectSupport { 041 042 private boolean requireSession = false; 043 044 private int cacheSeconds = -1; 045 046 047 /** 048 * Set whether a session should be required to handle requests. 049 */ 050 public final void setRequireSession(boolean requireSession) { 051 this.requireSession = requireSession; 052 } 053 054 /** 055 * Return whether a session is required to handle requests. 056 */ 057 public final boolean isRequireSession() { 058 return this.requireSession; 059 } 060 061 /** 062 * Cache content for the given number of seconds. Default is -1, 063 * indicating no override of portlet content caching. 064 * <p>Only if this is set to 0 (no cache) or a positive value (cache for 065 * this many seconds) will this class override the portlet settings. 066 * <p>The cache setting can be overwritten by subclasses, before content is generated. 067 */ 068 public final void setCacheSeconds(int seconds) { 069 this.cacheSeconds = seconds; 070 } 071 072 /** 073 * Return the number of seconds that content is cached. 074 */ 075 public final int getCacheSeconds() { 076 return this.cacheSeconds; 077 } 078 079 080 /** 081 * Check and prepare the given request and response according to the settings 082 * of this generator. Checks for a required session, and applies the number of 083 * cache seconds configured for this generator (if it is a render request/response). 084 * @param request current portlet request 085 * @param response current portlet response 086 * @throws PortletException if the request cannot be handled because a check failed 087 */ 088 protected final void check(PortletRequest request, PortletResponse response) throws PortletException { 089 if (this.requireSession) { 090 if (request.getPortletSession(false) == null) { 091 throw new PortletSessionRequiredException("Pre-existing session required but none found"); 092 } 093 } 094 } 095 096 /** 097 * Check and prepare the given request and response according to the settings 098 * of this generator. Checks for a required session, and applies the number of 099 * cache seconds configured for this generator (if it is a render request/response). 100 * @param request current portlet request 101 * @param response current portlet response 102 * @throws PortletException if the request cannot be handled because a check failed 103 */ 104 protected final void checkAndPrepare(PortletRequest request, MimeResponse response) 105 throws PortletException { 106 107 checkAndPrepare(request, response, this.cacheSeconds); 108 } 109 110 /** 111 * Check and prepare the given request and response according to the settings 112 * of this generator. Checks for a required session, and applies the given 113 * number of cache seconds (if it is a render request/response). 114 * @param request current portlet request 115 * @param response current portlet response 116 * @param cacheSeconds positive number of seconds into the future that the 117 * response should be cacheable for, 0 to prevent caching 118 * @throws PortletException if the request cannot be handled because a check failed 119 */ 120 protected final void checkAndPrepare(PortletRequest request, MimeResponse response, int cacheSeconds) 121 throws PortletException { 122 123 check(request, response); 124 applyCacheSeconds(response, cacheSeconds); 125 } 126 127 /** 128 * Prevent the render response from being cached. 129 */ 130 protected final void preventCaching(MimeResponse response) { 131 cacheForSeconds(response, 0); 132 } 133 134 /** 135 * Set portlet response to allow caching for the given number of seconds. 136 * @param response current portlet render response 137 * @param seconds number of seconds into the future that the response 138 * should be cacheable for 139 */ 140 protected final void cacheForSeconds(MimeResponse response, int seconds) { 141 response.setProperty(MimeResponse.EXPIRATION_CACHE, Integer.toString(seconds)); 142 } 143 144 /** 145 * Apply the given cache seconds to the render response 146 * @param response current portlet render response 147 * @param seconds positive number of seconds into the future that the 148 * response should be cacheable for, 0 to prevent caching 149 */ 150 protected final void applyCacheSeconds(MimeResponse response, int seconds) { 151 if (seconds > 0) { 152 cacheForSeconds(response, seconds); 153 } 154 else if (seconds == 0) { 155 preventCaching(response); 156 } 157 // Leave caching to the portlet configuration otherwise. 158 } 159 160}