SimpleSwitchLayoutAction


1   /*
2    * $Id: SimpleSwitchLayoutAction.java 54929 2004-10-16 16:38:42Z germuska $ 
3    *
4    * Copyright 1999-2004 The Apache Software Foundation.
5    * 
6    * Licensed under the Apache License, Version 2.0 (the "License");
7    * you may not use this file except in compliance with the License.
8    * 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, software
13   * distributed under the License is distributed on an "AS IS" BASIS,
14   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15   * See the License for the specific language governing permissions and
16   * limitations under the License.
17   */
18  
19  package org.apache.struts.webapp.tiles.skin;
20  
21  import javax.servlet.RequestDispatcher  ;
22  import javax.servlet.ServletContext  ;
23  import javax.servlet.ServletException  ;
24  import javax.servlet.http.HttpServletRequest  ;
25  import javax.servlet.http.HttpServletResponse  ;
26  import javax.servlet.http.HttpSession  ;
27  import org.apache.struts.action.ActionForm;
28  import org.apache.struts.action.ActionForward;
29  import org.apache.struts.action.ActionMapping;
30  import org.apache.struts.tiles.ComponentContext;
31  import org.apache.struts.tiles.DefinitionsFactoryException;
32  import org.apache.struts.tiles.actions.TilesAction;
33  
34    /**
35     * Simple Switch Layout
36     */
37  public class SimpleSwitchLayoutAction extends TilesAction
38  {
39      /** debug flag */
40    public static boolean debug = true;
41      /** Tile's attribute containing layout key */
42    public static final String   LAYOUT_ATTRIBUTE = "layout.attribute";
43      /** Tile attribute containing name used to store user settings in session context */
44    public static String   USER_SETTINGS_NAME_ATTRIBUTE = "userSettingsName";
45      /** Default name used to store settings in session context */
46    public static String   DEFAULT_USER_SETTINGS_NAME = "examples.tiles.skin.SELECTED_DEFINITION";
47  
48      /** Name of catalog in application context */
49    public static final String   CATALOG_NAME = "examples.tiles.skin.CATALOG_NAME";
50  
51      /** Default name used to store menu catalog in application scope */
52    public static String   DEFAULT_CATALOG_NAME = "tiles.examples.skin.layoutCatalog";
53      /** Tile attribute containing name used to store menu catalog in application scope */
54    public static String   CATALOG_NAME_ATTRIBUTE = "catalogName";
55      /** Tile attribute containing name of the settings definition used to initialize catalog */
56    public static final String   CATALOG_SETTING_ATTRIBUTE = "catalogSettings";
57  
58      /**
59       * Process the specified HTTP request, and create the corresponding HTTP
60       * response (or forward to another web component that will create it).
61       * Return an <code>ActionForward</code> instance describing where and how
62       * control should be forwarded, or <code>null</code> if the response has
63       * already been completed.
64       * This method should be implemented by subclasses.
65       *
66       * @param context The current Tile context, containing Tile attributes.
67       * @param mapping The ActionMapping used to select this instance.
68       * @param form The optional ActionForm bean for this request (if any).
69       * @param request The HTTP request we are processing.
70       * @param response The HTTP response we are creating.
71       *
72       * @exception Exception if the application business logic throws
73       *  an exception
74       */
75      public ActionForward execute(
76          ComponentContext context,
77          ActionMapping mapping,
78          ActionForm form,
79          HttpServletRequest   request,
80          HttpServletResponse   response)
81          throws Exception  
82      {
83      if(debug)
84        System.out.println( "Enter SimpleSwitchLayoutAction"  );
85  
86      String   layoutDir = "/layouts/";
87      String   userSelection = getUserSetting( context, request );
88      //String layout = "classicLayout.jsp";
89      String   layout = (String  )context.getAttribute( LAYOUT_ATTRIBUTE );
90      if(layout==null)
91        throw new ServletException  ( "Attribute '" + LAYOUT_ATTRIBUTE + "' is required." );
92  
93      String   layoutPath = layoutDir+userSelection+ "/" + layout;
94  
95      RequestDispatcher   rd = getServlet().getServletContext().getRequestDispatcher( layoutPath );
96      if(rd==null)
97        {
98        layoutPath = layoutDir + layout;
99        rd = getServlet().getServletContext().getRequestDispatcher( layoutPath );
100       if(rd==null)
101         throw new ServletException  ( "SwitchLayout error : Can't find layout '"
102                                   + layoutPath + "'." );
103       }
104     rd.include(request, response);
105     if(debug)
106       System.out.println( "Exit  SimpleSwitchLayoutAction"  );
107     return null;
108     }
109 
110     /**
111      * Retrieve key associated to user.
112      * This key denote a definition in catalog.
113      * Return user selected key, or "default" if none is set.
114      */
115   public static String   getUserSetting( ComponentContext context, HttpServletRequest   request )
116   {
117   HttpSession   session = request.getSession( false );
118   if( session == null )
119     return null;
120 
121     // Retrieve attribute name used to store settings.
122   String   userSettingsName = (String  )context.getAttribute( USER_SETTINGS_NAME_ATTRIBUTE );
123   if( userSettingsName == null )
124     userSettingsName = DEFAULT_USER_SETTINGS_NAME;
125 
126   return (String  )session.getAttribute(userSettingsName);
127   }
128 
129     /**
130      * Set user setting value.
131      * This key denote a definition in catalog.
132      * Return user selected key, or "default" if none is set.
133      */
134   public static void setUserSetting( ComponentContext context, HttpServletRequest   request, String   setting )
135   {
136   HttpSession   session = request.getSession();
137 
138     // Retrieve attribute name used to store settings.
139   String   userSettingsName = (String  )context.getAttribute( USER_SETTINGS_NAME_ATTRIBUTE );
140   if( userSettingsName == null )
141     userSettingsName = DEFAULT_USER_SETTINGS_NAME;
142 
143   session.setAttribute(userSettingsName, setting);
144   }
145 
146     /**
147      * Get catalog of available skins.
148      */
149   public static DefinitionCatalog getCatalog( ComponentContext context, HttpServletRequest   request, ServletContext   servletContext )
150     throws ServletException  
151   {
152     // Retrieve name used to store catalog in application context.
153     // If not found, use default name
154   String   catalogName = (String  )context.getAttribute( CATALOG_NAME_ATTRIBUTE );
155   if(catalogName == null)
156     catalogName = DEFAULT_CATALOG_NAME;
157 
158   if(debug)
159     System.out.println( "Catalog name=" + catalogName );
160   try
161     {
162     DefinitionCatalog catalog = (DefinitionCatalog)servletContext.getAttribute( catalogName );
163     if(catalog == null)
164       { // create catalog
165       if(debug)
166         System.out.println( "Create catalog" );
167       String   catalogSettings = (String  )context.getAttribute( CATALOG_SETTING_ATTRIBUTE );
168       if(catalogSettings == null)
169         throw new ServletException  ( "Error - CustomSkinAction : attribute '"
170                                   + CATALOG_SETTING_ATTRIBUTE
171                                   + "' not found in Tile's attributes. Need it to initialize catalog"  );
172       catalog = new DefinitionCatalog( catalogSettings, request, servletContext );
173       if(debug)
174         System.out.println( "Catalog created" );
175       servletContext.setAttribute( catalogName, catalog );
176       } // end if
177     return catalog;
178     }
179    catch(DefinitionsFactoryException ex )
180     {
181     if(debug)
182         System.out.println( "Exception : " + ex.getMessage() );
183     throw new ServletException  ( ex.getMessage() );
184     }
185   }
186 }
187
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