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: struberg $) 59 * @author Stan Silvert 60 * @version $Revision: 1188206 $ $Date: 2011-10-24 11:30:34 -0500 (Mon, 24 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", 80 since="1.1", group="state", tags="performance", 81 desc="Define the state method to be used. There are two different options " 82 + "defined by the specification: 'client' and 'server' state.") 83 public static final String STATE_SAVING_METHOD_PARAM_NAME = "javax.faces.STATE_SAVING_METHOD"; 84 public static final String STATE_SAVING_METHOD_CLIENT = "client"; 85 public static final String STATE_SAVING_METHOD_SERVER = "server"; 86 87 /** 88 * Indicate the viewId(s) separated by commas that should be saved and restored fully, 89 * without use Partial State Saving (PSS). 90 */ 91 @JSFWebConfigParam(since="2.0", group="state") 92 public static final String FULL_STATE_SAVING_VIEW_IDS_PARAM_NAME = "javax.faces.FULL_STATE_SAVING_VIEW_IDS"; 93 94 /** 95 * Enable or disable partial state saving algorithm. 96 * 97 * <p>Partial State Saving algorithm allows to reduce the size of the state required to save a view, 98 * keeping track of the "delta" or differences between the view build by first time and the current 99 * state of the view.</p> 100 * <p>If the webapp faces-config file version is 2.0 or upper the default value is true, otherwise is false.</p> 101 */ 102 @JSFWebConfigParam(expectedValues="true,false", since="2.0", defaultValue="true (false with 1.2 webapps)", 103 tags="performance", group="state") 104 public static final String PARTIAL_STATE_SAVING_PARAM_NAME = "javax.faces.PARTIAL_STATE_SAVING"; 105 private Boolean _savingStateInClient = null; 106 107 public static final String IS_BUILDING_INITIAL_STATE = "javax.faces.IS_BUILDING_INITIAL_STATE"; 108 109 public static final String IS_SAVING_STATE = "javax.faces.IS_SAVING_STATE"; 110 111 /** 112 * Invokes getTreeStructureToSave and getComponentStateToSave, then return an object that wraps the two resulting 113 * objects. This object can then be passed to method writeState. 114 * <p> 115 * Deprecated; use saveView instead. 116 * 117 * @deprecated 118 */ 119 public StateManager.SerializedView saveSerializedView(FacesContext context) 120 { 121 Object savedView = saveView(context); 122 if (savedView != null && savedView instanceof Object[]) 123 { 124 Object[] structureAndState = (Object[]) savedView; 125 if (structureAndState.length == 2) 126 { 127 return new StateManager.SerializedView(structureAndState[0], structureAndState[1]); 128 } 129 } 130 131 return null; 132 } 133 134 /** 135 * Returns an object that is sufficient to recreate the component tree that is the viewroot of the specified 136 * context. 137 * <p> 138 * The return value is suitable for passing to method writeState. 139 * 140 * @since 1.2 141 */ 142 public Object saveView(FacesContext context) 143 { 144 StateManager.SerializedView serializedView = saveSerializedView(context); 145 if (serializedView == null) 146 { 147 return null; 148 } 149 150 Object[] structureAndState = new Object[2]; 151 structureAndState[0] = serializedView.getStructure(); 152 structureAndState[1] = serializedView.getState(); 153 154 return structureAndState; 155 } 156 157 /** 158 * Return data that is sufficient to recreate the component tree that is the viewroot of the specified context, but 159 * without restoring the state in the components. 160 * <p> 161 * Using this data, a tree of components which has the same "shape" as the original component tree can be recreated. 162 * However the component instances themselves will have only their default values, ie their member fields will not 163 * have been set to the original values. 164 * <p> 165 * Deprecated; use saveView instead. 166 * 167 * @deprecated 168 */ 169 protected Object getTreeStructureToSave(FacesContext context) 170 { 171 return null; 172 } 173 174 /** 175 * Return data that can be applied to a component tree created using the "getTreeStructureToSave" method. 176 * <p> 177 * Deprecated; use saveView instead. 178 * 179 * @deprecated 180 */ 181 protected Object getComponentStateToSave(FacesContext context) 182 { 183 return null; 184 } 185 186 /** 187 * Associate the provided state object with the current response being generated. 188 * <p> 189 * When client-side state is enabled, it is expected that method writes the data contained in the state parameter to 190 * the response somehow. 191 * <p> 192 * When server-side state is enabled, at most a "token" is expected to be written. 193 * <p> 194 * Deprecated; use writeState(FacesContext, Object) instead. This method was abstract in JSF1.1, but is now an empty 195 * non-abstract method so that old classes that implement this method continue to work, while new classes can just 196 * override the new writeState method rather than this one. 197 * 198 * @throws IOException 199 * never 200 * 201 * @deprecated 202 */ 203 public void writeState(FacesContext context, StateManager.SerializedView state) 204 throws IOException 205 { 206 if (state != null) 207 { 208 writeState(context, new Object[]{state.getStructure(), state.getState()}); 209 } 210 } 211 212 /** 213 * Associate the provided state object with the current response being generated. 214 * <p> 215 * When client-side state is enabled, it is expected that method writes the data contained in the state parameter to 216 * the response somehow. 217 * <p> 218 * When server-side state is enabled, at most a "token" is expected to be written. 219 * <p> 220 * This method should be overridden by subclasses. It is not abstract because a default implementation is provided 221 * that forwards to the old writeState method; this allows subclasses of StateManager written using the JSF1.1 API 222 * to continue to work. 223 * <p> 224 * 225 * @since 1.2 226 */ 227 public void writeState(FacesContext context, Object state) throws IOException 228 { 229 if (!(state instanceof Object[])) 230 { 231 return; 232 } 233 Object[] structureAndState = (Object[]) state; 234 if (structureAndState.length < 2) 235 { 236 return; 237 } 238 239 writeState(context, new StateManager.SerializedView(structureAndState[0], structureAndState[1])); 240 } 241 242 /** 243 * TODO: This method should be called from somewhere when ajax response is created to update the state saving param 244 * on client. The place where this method is called is an implementation detail, so there is no references about 245 * from where in the spec javadoc. 246 * 247 * @since 2.0 248 * @param context 249 * @return 250 */ 251 public String getViewState(FacesContext context) 252 { 253 return context.getRenderKit().getResponseStateManager().getViewState(context, saveView(context)); 254 } 255 256 public abstract UIViewRoot restoreView(FacesContext context, String viewId, String renderKitId); 257 258 /** 259 * @deprecated 260 */ 261 protected UIViewRoot restoreTreeStructure(FacesContext context, String viewId, String renderKitId) 262 { 263 return null; 264 } 265 266 /** 267 * @deprecated 268 */ 269 protected void restoreComponentState(FacesContext context, UIViewRoot viewRoot, String renderKitId) 270 { 271 // default impl does nothing as per JSF 1.2 javadoc 272 } 273 274 public boolean isSavingStateInClient(FacesContext context) 275 { 276 if (context == null) 277 { 278 throw new NullPointerException("context"); 279 } 280 if (_savingStateInClient != null) 281 { 282 return _savingStateInClient.booleanValue(); 283 } 284 285 String stateSavingMethod = context.getExternalContext().getInitParameter(STATE_SAVING_METHOD_PARAM_NAME); 286 if (stateSavingMethod == null) 287 { 288 _savingStateInClient = Boolean.FALSE; // Specs 10.1.3: default server saving 289 context.getExternalContext().log("No state saving method defined, assuming default server state saving"); 290 } 291 else if (stateSavingMethod.equals(STATE_SAVING_METHOD_CLIENT)) 292 { 293 _savingStateInClient = Boolean.TRUE; 294 } 295 else if (stateSavingMethod.equals(STATE_SAVING_METHOD_SERVER)) 296 { 297 _savingStateInClient = Boolean.FALSE; 298 } 299 else 300 { 301 _savingStateInClient = Boolean.FALSE; // Specs 10.1.3: default server saving 302 context.getExternalContext().log( 303 "Illegal state saving method '" + stateSavingMethod + "', default server state saving will be used"); 304 } 305 return _savingStateInClient.booleanValue(); 306 } 307 308 /** 309 * @deprecated 310 */ 311 public class SerializedView 312 { 313 private Object _structure; 314 private Object _state; 315 316 /** 317 * @deprecated 318 */ 319 public SerializedView(Object structure, Object state) 320 { 321 _structure = structure; 322 _state = state; 323 } 324 325 /** 326 * @deprecated 327 */ 328 public Object getStructure() 329 { 330 return _structure; 331 } 332 333 /** 334 * @deprecated 335 */ 336 public Object getState() 337 { 338 return _state; 339 } 340 } 341 }