001// Copyright 2007, 2008, 2010 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.tapestry5.internal.services; 016 017import static org.apache.tapestry5.ioc.internal.util.CollectionFactory.newConcurrentMap; 018 019import java.util.Map; 020 021import org.apache.tapestry5.ioc.ObjectLocator; 022import org.apache.tapestry5.services.ApplicationStateContribution; 023import org.apache.tapestry5.services.ApplicationStateCreator; 024import org.apache.tapestry5.services.ApplicationStateManager; 025import org.apache.tapestry5.services.ApplicationStatePersistenceStrategy; 026import org.apache.tapestry5.services.ApplicationStatePersistenceStrategySource; 027 028public class ApplicationStateManagerImpl implements ApplicationStateManager 029{ 030 static final String DEFAULT_STRATEGY = "session"; 031 032 static class ApplicationStateAdapter<T> 033 { 034 private final Class<T> ssoClass; 035 036 private final ApplicationStatePersistenceStrategy strategy; 037 038 private final ApplicationStateCreator<T> creator; 039 040 ApplicationStateAdapter(Class<T> ssoClass, ApplicationStatePersistenceStrategy strategy, 041 ApplicationStateCreator<T> creator) 042 { 043 this.ssoClass = ssoClass; 044 this.strategy = strategy; 045 this.creator = creator; 046 } 047 048 T getOrCreate() 049 { 050 return strategy.get(ssoClass, creator); 051 } 052 053 void set(T sso) 054 { 055 strategy.set(ssoClass, sso); 056 } 057 058 boolean exists() 059 { 060 return strategy.exists(ssoClass); 061 } 062 } 063 064 /** 065 * The map will be extended periodically as new ASOs, not in the configuration, are encountered. 066 * Thut is is thread 067 * safe. 068 */ 069 private final Map<Class, ApplicationStateAdapter> classToAdapter = newConcurrentMap(); 070 071 private final ApplicationStatePersistenceStrategySource source; 072 073 private final ObjectLocator locator; 074 075 @SuppressWarnings("unchecked") 076 public ApplicationStateManagerImpl(Map<Class, ApplicationStateContribution> configuration, 077 ApplicationStatePersistenceStrategySource source, ObjectLocator locator) 078 { 079 this.source = source; 080 this.locator = locator; 081 082 for (Class asoClass : configuration.keySet()) 083 { 084 ApplicationStateContribution contribution = configuration.get(asoClass); 085 086 ApplicationStateAdapter adapter = newAdapter(asoClass, contribution.getStrategy(), 087 contribution.getCreator()); 088 089 classToAdapter.put(asoClass, adapter); 090 } 091 092 } 093 094 @SuppressWarnings("unchecked") 095 private <T> ApplicationStateAdapter<T> newAdapter(final Class<T> ssoClass, String strategyName, 096 ApplicationStateCreator<T> creator) 097 { 098 if (creator == null) 099 { 100 creator = new ApplicationStateCreator<T>() 101 { 102 public T create() 103 { 104 return locator.autobuild("Instantiating instance of SSO class " 105 + ssoClass.getName(), ssoClass); 106 } 107 }; 108 } 109 110 ApplicationStatePersistenceStrategy strategy = source.get(strategyName); 111 112 return new ApplicationStateAdapter(ssoClass, strategy, creator); 113 } 114 115 @SuppressWarnings("unchecked") 116 private <T> ApplicationStateAdapter<T> getAdapter(Class<T> ssoClass) 117 { 118 ApplicationStateAdapter<T> result = classToAdapter.get(ssoClass); 119 120 // Not found is completely OK, we'll define it on the fly. 121 122 if (result == null) 123 { 124 result = newAdapter(ssoClass, DEFAULT_STRATEGY, null); 125 classToAdapter.put(ssoClass, result); 126 } 127 128 return result; 129 } 130 131 public <T> T get(Class<T> ssoClass) 132 { 133 return getAdapter(ssoClass).getOrCreate(); 134 } 135 136 public <T> T getIfExists(Class<T> ssoClass) 137 { 138 ApplicationStateAdapter<T> adapter = getAdapter(ssoClass); 139 140 return adapter.exists() ? adapter.getOrCreate() : null; 141 } 142 143 public <T> void set(Class<T> ssoClass, T sso) 144 { 145 getAdapter(ssoClass).set(sso); 146 } 147 148 public <T> boolean exists(Class<T> ssoClass) 149 { 150 return getAdapter(ssoClass).exists(); 151 } 152 153}