1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to you under the Apache License, Version 2.0 (the 7 * "License"); you may not use this file except in compliance 8 * with the License. You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, 13 * software distributed under the License is distributed on an 14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 15 * KIND, either express or implied. See the License for the 16 * specific language governing permissions and limitations 17 * under the License. 18 */ 19 package javax.faces.application; 20 21 22 import org.apache.myfaces.buildtools.maven2.plugin.builder.annotation.JSFWebConfigParam; 23 24 import java.io.IOException; 25 26 import javax.faces.component.UIViewRoot; 27 import javax.faces.context.FacesContext; 28 29 /** 30 * Responsible for storing sufficient information about a component tree so that an identical tree can later be 31 * recreated. 32 * <p> 33 * It is up to the concrete implementation to decide whether to use information from the "view template" that was used 34 * to first create the view, or whether to store sufficient information to enable the view to be restored without any 35 * reference to the original template. However as JSF components have mutable fields that can be set by code, and 36 * affected by user input, at least some state does need to be kept in order to recreate a previously-existing component 37 * tree. 38 * <p> 39 * There are two different options defined by the specification: "client" and "server" state. 40 * <p> 41 * When "client" state is configured, all state information required to create the tree is embedded within the data 42 * rendered to the client. Note that because data received from a remote client must always be treated as "tainted", 43 * care must be taken when using such data. Some StateManager implementations may use encryption to ensure that clients 44 * cannot modify the data, and that the data received on postback is therefore trustworthy. 45 * <p> 46 * When "server" state is configured, the data is saved somewhere "on the back end", and (at most) a token is embedded 47 * in the data rendered to the user. 48 * <p> 49 * This class is usually invoked by a concrete implementation of ViewHandler. 50 * <p> 51 * Note that class ViewHandler isolates JSF components from the details of the request format. This class isolates JSF 52 * components from the details of the response format. Because request and response are usually tightly coupled, the 53 * StateManager and ViewHandler implementations are also usually fairly tightly coupled (ie the ViewHandler/StateManager 54 * implementations come as pairs). 55 * <p> 56 * See also the <a href="http://java.sun.com/javaee/javaserverfaces/1.2/docs/api/index.html">JSF Specification</a> 57 * 58 * @author Manfred Geiler (latest modification by $Author: bommel $) 59 * @author Stan Silvert 60 * @version $Revision: 1187700 $ $Date: 2011-10-22 07:19:37 -0500 (Sat, 22 Oct 2011) $ 61 */ 62 public abstract class StateManager 63 { 64 /** 65 * Define the state method to be used. There are two different options defined by the 66 * specification: "client" and "server" state. 67 * <p> 68 * When "client" state is configured, all state information required to create the tree is embedded within 69 * the data rendered to the client. Note that because data received from a remote client must always be 70 * treated as "tainted", care must be taken when using such data. Some StateManager implementations may 71 * use encryption to ensure that clients cannot modify the data, and that the data received on postback 72 * is therefore trustworthy. 73 * </p> 74 * <p> 75 * When "server" state is configured, the data is saved somewhere "on the back end", and (at most) a 76 * token is embedded in the data rendered to the user. 77 * </p> 78 */ 79 @JSFWebConfigParam(defaultValue="server", expectedValues="server,client", since="1.1", group="state", tags="performance", 80 desc="Define the state method to be used. There are two different options defined by the specification: 'client' and 'server' state.") 81 public static final String STATE_SAVING_METHOD_PARAM_NAME = "javax.faces.STATE_SAVING_METHOD"; 82 public static final String STATE_SAVING_METHOD_CLIENT = "client"; 83 public static final String STATE_SAVING_METHOD_SERVER = "server"; 84 85 /** 86 * Indicate the viewId(s) separated by commas that should be saved and restored fully, without use Partial State Saving (PSS). 87 */ 88 @JSFWebConfigParam(since="2.0", group="state") 89 public static final String FULL_STATE_SAVING_VIEW_IDS_PARAM_NAME = "javax.faces.FULL_STATE_SAVING_VIEW_IDS"; 90 91 /** 92 * Enable or disable partial state saving algorithm. 93 * 94 * <p>Partial State Saving algorithm allows to reduce the size of the state required to save a view, 95 * keeping track of the "delta" or differences between the view build by first time and the current 96 * state of the view.</p> 97 * <p>If the webapp faces-config file version is 2.0 or upper the default value is true, otherwise is false.</p> 98 */ 99 @JSFWebConfigParam(expectedValues="true,false", since="2.0", defaultValue="true (false with 1.2 webapps)", tags="performance", group="state") 100 public static final String PARTIAL_STATE_SAVING_PARAM_NAME = "javax.faces.PARTIAL_STATE_SAVING"; 101 private Boolean _savingStateInClient = null; 102 103 /** 104 * Invokes getTreeStructureToSave and getComponentStateToSave, then return an object that wraps the two resulting 105 * objects. This object can then be passed to method writeState. 106 * <p> 107 * Deprecated; use saveView instead. 108 * 109 * @deprecated 110 */ 111 public StateManager.SerializedView saveSerializedView(FacesContext context) 112 { 113 Object savedView = saveView(context); 114 if (savedView != null && savedView instanceof Object[]) 115 { 116 Object[] structureAndState = (Object[]) savedView; 117 if (structureAndState.length == 2) 118 { 119 return new StateManager.SerializedView(structureAndState[0], structureAndState[1]); 120 } 121 } 122 123 return null; 124 } 125 126 /** 127 * Returns an object that is sufficient to recreate the component tree that is the viewroot of the specified 128 * context. 129 * <p> 130 * The return value is suitable for passing to method writeState. 131 * 132 * @since 1.2 133 */ 134 public Object saveView(FacesContext context) 135 { 136 StateManager.SerializedView serializedView = saveSerializedView(context); 137 if (serializedView == null) 138 return null; 139 140 Object[] structureAndState = new Object[2]; 141 structureAndState[0] = serializedView.getStructure(); 142 structureAndState[1] = serializedView.getState(); 143 144 return structureAndState; 145 } 146 147 /** 148 * Return data that is sufficient to recreate the component tree that is the viewroot of the specified context, but 149 * without restoring the state in the components. 150 * <p> 151 * Using this data, a tree of components which has the same "shape" as the original component tree can be recreated. 152 * However the component instances themselves will have only their default values, ie their member fields will not 153 * have been set to the original values. 154 * <p> 155 * Deprecated; use saveView instead. 156 * 157 * @deprecated 158 */ 159 protected Object getTreeStructureToSave(FacesContext context) 160 { 161 return null; 162 } 163 164 /** 165 * Return data that can be applied to a component tree created using the "getTreeStructureToSave" method. 166 * <p> 167 * Deprecated; use saveView instead. 168 * 169 * @deprecated 170 */ 171 protected Object getComponentStateToSave(FacesContext context) 172 { 173 return null; 174 } 175 176 /** 177 * Associate the provided state object with the current response being generated. 178 * <p> 179 * When client-side state is enabled, it is expected that method writes the data contained in the state parameter to 180 * the response somehow. 181 * <p> 182 * When server-side state is enabled, at most a "token" is expected to be written. 183 * <p> 184 * Deprecated; use writeState(FacesContext, Object) instead. This method was abstract in JSF1.1, but is now an empty 185 * non-abstract method so that old classes that implement this method continue to work, while new classes can just 186 * override the new writeState method rather than this one. 187 * 188 * @throws IOException 189 * never 190 * 191 * @deprecated 192 */ 193 public void writeState(FacesContext context, StateManager.SerializedView state) 194 throws IOException 195 { 196 if (state != null) 197 { 198 writeState(context, new Object[]{state.getStructure(), state.getState()}); 199 } 200 } 201 202 /** 203 * Associate the provided state object with the current response being generated. 204 * <p> 205 * When client-side state is enabled, it is expected that method writes the data contained in the state parameter to 206 * the response somehow. 207 * <p> 208 * When server-side state is enabled, at most a "token" is expected to be written. 209 * <p> 210 * This method should be overridden by subclasses. It is not abstract because a default implementation is provided 211 * that forwards to the old writeState method; this allows subclasses of StateManager written using the JSF1.1 API 212 * to continue to work. 213 * <p> 214 * 215 * @since 1.2 216 */ 217 public void writeState(FacesContext context, Object state) throws IOException 218 { 219 if (!(state instanceof Object[])) 220 return; 221 Object[] structureAndState = (Object[]) state; 222 if (structureAndState.length < 2) 223 return; 224 225 writeState(context, new StateManager.SerializedView(structureAndState[0], structureAndState[1])); 226 } 227 228 /** 229 * TODO: This method should be called from somewhere when ajax response is created to update the state saving param 230 * on client. The place where this method is called is an implementation detail, so there is no references about 231 * from where in the spec javadoc. 232 * 233 * @since 2.0 234 * @param context 235 * @return 236 */ 237 public String getViewState(FacesContext context) 238 { 239 return context.getRenderKit().getResponseStateManager().getViewState(context, saveView(context)); 240 } 241 242 public abstract UIViewRoot restoreView(FacesContext context, String viewId, String renderKitId); 243 244 /** 245 * @deprecated 246 */ 247 protected UIViewRoot restoreTreeStructure(FacesContext context, String viewId, String renderKitId) 248 { 249 return null; 250 } 251 252 /** 253 * @deprecated 254 */ 255 protected void restoreComponentState(FacesContext context, UIViewRoot viewRoot, String renderKitId) 256 { 257 // default impl does nothing as per JSF 1.2 javadoc 258 } 259 260 public boolean isSavingStateInClient(FacesContext context) 261 { 262 if (context == null) 263 throw new NullPointerException("context"); 264 if (_savingStateInClient != null) 265 return _savingStateInClient.booleanValue(); 266 String stateSavingMethod = context.getExternalContext().getInitParameter(STATE_SAVING_METHOD_PARAM_NAME); 267 if (stateSavingMethod == null) 268 { 269 _savingStateInClient = Boolean.FALSE; // Specs 10.1.3: default server saving 270 context.getExternalContext().log("No state saving method defined, assuming default server state saving"); 271 } 272 else if (stateSavingMethod.equals(STATE_SAVING_METHOD_CLIENT)) 273 { 274 _savingStateInClient = Boolean.TRUE; 275 } 276 else if (stateSavingMethod.equals(STATE_SAVING_METHOD_SERVER)) 277 { 278 _savingStateInClient = Boolean.FALSE; 279 } 280 else 281 { 282 _savingStateInClient = Boolean.FALSE; // Specs 10.1.3: default server saving 283 context.getExternalContext().log( 284 "Illegal state saving method '" + stateSavingMethod + "', default server state saving will be used"); 285 } 286 return _savingStateInClient.booleanValue(); 287 } 288 289 /** 290 * @deprecated 291 */ 292 public class SerializedView 293 { 294 private Object _structure; 295 private Object _state; 296 297 /** 298 * @deprecated 299 */ 300 public SerializedView(Object structure, Object state) 301 { 302 _structure = structure; 303 _state = state; 304 } 305 306 /** 307 * @deprecated 308 */ 309 public Object getStructure() 310 { 311 return _structure; 312 } 313 314 /** 315 * @deprecated 316 */ 317 public Object getState() 318 { 319 return _state; 320 } 321 } 322 }