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 public abstract class StateManager 59 { 60 /** 61 * Define the state method to be used. There are two different options defined by the 62 * specification: "client" and "server" state. 63 * <p> 64 * When "client" state is configured, all state information required to create the tree is embedded within 65 * the data rendered to the client. Note that because data received from a remote client must always be 66 * treated as "tainted", care must be taken when using such data. Some StateManager implementations may 67 * use encryption to ensure that clients cannot modify the data, and that the data received on postback 68 * is therefore trustworthy. 69 * </p> 70 * <p> 71 * When "server" state is configured, the data is saved somewhere "on the back end", and (at most) a 72 * token is embedded in the data rendered to the user. 73 * </p> 74 */ 75 @JSFWebConfigParam(defaultValue="server", expectedValues="server,client", 76 since="1.1", group="state", tags="performance", ignoreUpperLowerCase = true, 77 desc="Define the state method to be used. There are two different options " 78 + "defined by the specification: 'client' and 'server' state.") 79 public static final String STATE_SAVING_METHOD_PARAM_NAME = "javax.faces.STATE_SAVING_METHOD"; 80 public static final String STATE_SAVING_METHOD_CLIENT = "client"; 81 public static final String STATE_SAVING_METHOD_SERVER = "server"; 82 83 /** 84 * Indicate the viewId(s) separated by commas that should be saved and restored fully, 85 * without use Partial State Saving (PSS). 86 */ 87 @JSFWebConfigParam(since="2.0", group="state") 88 public static final String FULL_STATE_SAVING_VIEW_IDS_PARAM_NAME = "javax.faces.FULL_STATE_SAVING_VIEW_IDS"; 89 90 /** 91 * Enable or disable partial state saving algorithm. 92 * 93 * <p>Partial State Saving algorithm allows to reduce the size of the state required to save a view, 94 * keeping track of the "delta" or differences between the view build by first time and the current 95 * state of the view.</p> 96 * <p>If the webapp faces-config file version is 2.0 or upper the default value is true, otherwise is false.</p> 97 */ 98 @JSFWebConfigParam(expectedValues="true,false", since="2.0", defaultValue="true (false with 1.2 webapps)", 99 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 public static final String IS_BUILDING_INITIAL_STATE = "javax.faces.IS_BUILDING_INITIAL_STATE"; 104 105 public static final String IS_SAVING_STATE = "javax.faces.IS_SAVING_STATE"; 106 107 /** 108 * Indicate if the state should be serialized before save it on the session. 109 * <p> 110 * Only applicable if state saving method is "server" (= default). 111 * If <code>true</code> (default) the state will be serialized to a byte stream before it is 112 * written to the session. 113 * If <code>false</code> the state will not be serialized to a byte stream. 114 * </p> 115 */ 116 @JSFWebConfigParam(since="2.2", group="state", tags="performance", 117 defaultValue="false", expectedValues="true,false") 118 public static final java.lang.String SERIALIZE_SERVER_STATE_PARAM_NAME = "javax.faces.SERIALIZE_SERVER_STATE"; 119 120 /** 121 * Invokes getTreeStructureToSave and getComponentStateToSave, then return an object that wraps the two resulting 122 * objects. This object can then be passed to method writeState. 123 * <p> 124 * Deprecated; use saveView instead. 125 * 126 * @deprecated 127 */ 128 public StateManager.SerializedView saveSerializedView(FacesContext context) 129 { 130 Object savedView = saveView(context); 131 if (savedView != null && savedView instanceof Object[]) 132 { 133 Object[] structureAndState = (Object[]) savedView; 134 if (structureAndState.length == 2) 135 { 136 return new StateManager.SerializedView(structureAndState[0], structureAndState[1]); 137 } 138 } 139 140 return null; 141 } 142 143 /** 144 * Returns an object that is sufficient to recreate the component tree that is the viewroot of the specified 145 * context. 146 * <p> 147 * The return value is suitable for passing to method writeState. 148 * 149 * @since 1.2 150 */ 151 @Deprecated 152 public Object saveView(FacesContext context) 153 { 154 StateManager.SerializedView serializedView = saveSerializedView(context); 155 if (serializedView == null) 156 { 157 return null; 158 } 159 160 Object[] structureAndState = new Object[2]; 161 structureAndState[0] = serializedView.getStructure(); 162 structureAndState[1] = serializedView.getState(); 163 164 return structureAndState; 165 } 166 167 /** 168 * Return data that is sufficient to recreate the component tree that is the viewroot of the specified context, but 169 * without restoring the state in the components. 170 * <p> 171 * Using this data, a tree of components which has the same "shape" as the original component tree can be recreated. 172 * However the component instances themselves will have only their default values, ie their member fields will not 173 * have been set to the original values. 174 * <p> 175 * Deprecated; use saveView instead. 176 * 177 * @deprecated 178 */ 179 protected Object getTreeStructureToSave(FacesContext context) 180 { 181 return null; 182 } 183 184 /** 185 * Return data that can be applied to a component tree created using the "getTreeStructureToSave" method. 186 * <p> 187 * Deprecated; use saveView instead. 188 * 189 * @deprecated 190 */ 191 protected Object getComponentStateToSave(FacesContext context) 192 { 193 return null; 194 } 195 196 /** 197 * Associate the provided state object with the current response being generated. 198 * <p> 199 * When client-side state is enabled, it is expected that method writes the data contained in the state parameter to 200 * the response somehow. 201 * <p> 202 * When server-side state is enabled, at most a "token" is expected to be written. 203 * <p> 204 * Deprecated; use writeState(FacesContext, Object) instead. This method was abstract in JSF1.1, but is now an empty 205 * non-abstract method so that old classes that implement this method continue to work, while new classes can just 206 * override the new writeState method rather than this one. 207 * 208 * @throws IOException 209 * never 210 * 211 * @deprecated 212 */ 213 public void writeState(FacesContext context, StateManager.SerializedView state) 214 throws IOException 215 { 216 if (state != null) 217 { 218 writeState(context, new Object[]{state.getStructure(), state.getState()}); 219 } 220 } 221 222 /** 223 * Associate the provided state object with the current response being generated. 224 * <p> 225 * When client-side state is enabled, it is expected that method writes the data contained in the state parameter to 226 * the response somehow. 227 * <p> 228 * When server-side state is enabled, at most a "token" is expected to be written. 229 * <p> 230 * This method should be overridden by subclasses. It is not abstract because a default implementation is provided 231 * that forwards to the old writeState method; this allows subclasses of StateManager written using the JSF1.1 API 232 * to continue to work. 233 * <p> 234 * 235 * @since 1.2 236 */ 237 public void writeState(FacesContext context, Object state) throws IOException 238 { 239 if (!(state instanceof Object[])) 240 { 241 return; 242 } 243 Object[] structureAndState = (Object[]) state; 244 if (structureAndState.length < 2) 245 { 246 return; 247 } 248 249 writeState(context, new StateManager.SerializedView(structureAndState[0], structureAndState[1])); 250 } 251 252 /** 253 * TODO: This method should be called from somewhere when ajax response is created to update the state saving param 254 * on client. The place where this method is called is an implementation detail, so there is no references about 255 * from where in the spec javadoc. 256 * 257 * @since 2.0 258 * @param context 259 * @return 260 */ 261 public String getViewState(FacesContext context) 262 { 263 return context.getRenderKit().getResponseStateManager().getViewState(context, saveView(context)); 264 } 265 266 @Deprecated 267 public abstract UIViewRoot restoreView(FacesContext context, String viewId, String renderKitId); 268 269 /** 270 * @deprecated 271 */ 272 protected UIViewRoot restoreTreeStructure(FacesContext context, String viewId, String renderKitId) 273 { 274 return null; 275 } 276 277 /** 278 * @deprecated 279 */ 280 protected void restoreComponentState(FacesContext context, UIViewRoot viewRoot, String renderKitId) 281 { 282 // default impl does nothing as per JSF 1.2 javadoc 283 } 284 285 public boolean isSavingStateInClient(FacesContext context) 286 { 287 if (context == null) 288 { 289 throw new NullPointerException("context"); 290 } 291 if (_savingStateInClient != null) 292 { 293 return _savingStateInClient.booleanValue(); 294 } 295 296 String stateSavingMethod = context.getExternalContext().getInitParameter(STATE_SAVING_METHOD_PARAM_NAME); 297 if (stateSavingMethod == null) 298 { 299 _savingStateInClient = Boolean.FALSE; // Specs 10.1.3: default server saving 300 context.getExternalContext().log("No state saving method defined, assuming default server state saving"); 301 } 302 else if (stateSavingMethod.equalsIgnoreCase(STATE_SAVING_METHOD_CLIENT)) 303 { 304 _savingStateInClient = Boolean.TRUE; 305 } 306 else if (stateSavingMethod.equalsIgnoreCase(STATE_SAVING_METHOD_SERVER)) 307 { 308 _savingStateInClient = Boolean.FALSE; 309 } 310 else 311 { 312 _savingStateInClient = Boolean.FALSE; // Specs 10.1.3: default server saving 313 context.getExternalContext().log( 314 "Illegal state saving method '" + stateSavingMethod + "', default server state saving will be used"); 315 } 316 return _savingStateInClient.booleanValue(); 317 } 318 319 /** 320 * @deprecated 321 */ 322 public class SerializedView 323 { 324 private Object _structure; 325 private Object _state; 326 327 /** 328 * @deprecated 329 */ 330 public SerializedView(Object structure, Object state) 331 { 332 _structure = structure; 333 _state = state; 334 } 335 336 /** 337 * @deprecated 338 */ 339 public Object getStructure() 340 { 341 return _structure; 342 } 343 344 /** 345 * @deprecated 346 */ 347 public Object getState() 348 { 349 return _state; 350 } 351 } 352 }