001// Copyright 2005 The Apache Software Foundation 002// 003// Licensed under the Apache License, Version 2.0 (the "License"); 004// you may not use this file except in compliance with the License. 005// You may obtain a copy of the License at 006// 007// http://www.apache.org/licenses/LICENSE-2.0 008// 009// Unless required by applicable law or agreed to in writing, software 010// distributed under the License is distributed on an "AS IS" BASIS, 011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 012// See the License for the specific language governing permissions and 013// limitations under the License. 014 015package org.apache.tapestry.engine.state; 016 017import org.apache.tapestry.SessionStoreOptimized; 018import org.apache.tapestry.web.WebRequest; 019import org.apache.tapestry.web.WebSession; 020 021/** 022 * Manager for the 'session' scope; state objects are stored as HttpSession attributes. The 023 * HttpSession is created as necessary. 024 * 025 * @author Howard M. Lewis Ship 026 * @since 4.0 027 */ 028public class SessionScopeManager implements StateObjectPersistenceManager 029{ 030 private WebRequest _request; 031 032 private String _applicationId; 033 034 private String buildKey(String objectName) 035 { 036 // For Portlets, the application id is going to be somewhat redundant, since 037 // the Portlet API keeps portlets seperate anyway. 038 039 return "state:" + _applicationId + ":" + objectName; 040 } 041 042 /** 043 * Returns the session for the current request, creating it if necessary. 044 */ 045 046 private WebSession getSession() 047 { 048 return _request.getSession(true); 049 } 050 051 public boolean exists(String objectName) 052 { 053 WebSession session = _request.getSession(false); 054 055 if (session == null) 056 return false; 057 058 return session.getAttribute(buildKey(objectName)) != null; 059 } 060 061 public Object get(String objectName, StateObjectFactory factory) 062 { 063 String key = buildKey(objectName); 064 WebSession session = getSession(); 065 066 Object result = session.getAttribute(key); 067 if (result == null) 068 { 069 result = factory.createStateObject(); 070 session.setAttribute(key, result); 071 } 072 073 return result; 074 } 075 076 public void store(String objectName, Object stateObject) 077 { 078 if (stateObject instanceof SessionStoreOptimized) 079 { 080 SessionStoreOptimized optimized = (SessionStoreOptimized) stateObject; 081 082 if (!optimized.isStoreToSessionNeeded()) 083 return; 084 } 085 086 String key = buildKey(objectName); 087 088 WebSession session = getSession(); 089 090 session.setAttribute(key, stateObject); 091 } 092 093 public void setApplicationId(String applicationName) 094 { 095 _applicationId = applicationName; 096 } 097 098 public void setRequest(WebRequest request) 099 { 100 _request = request; 101 } 102}