/*
* $Header: /home/cvs/jakarta-struts/src/tiles-documentation/org/apache/struts/webapp/tiles/skin/LayoutSwitchAction.java,v 1.2 2003/02/28 02:23:05 dgraham Exp $
* $Revision: 1.2 $
* $Date: 2003/02/28 02:23:05 $
*
* ====================================================================
*
* The Apache Software License, Version 1.1
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* "This product includes software developed by the
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package org.apache.struts.webapp.tiles.skin;
import java.io.IOException;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.tiles.ComponentContext;
import org.apache.struts.tiles.ComponentDefinition;
import org.apache.struts.tiles.DefinitionsFactoryException;
import org.apache.struts.tiles.actions.TilesAction;
/**
* Customize layouts according to predefined "skin"
* A "skin" is a set of layouts used together to provide a consistent
* Look & Feel.
* This action is called when inserting a definition's layout. It replaces
* definition's layout by the one set in selected skin.
* the appropriate
* Available skins are stored in application context. They are initialized from
* a Tile definition.
* Currently selected skin is stored under user session, if any. Otherwise,
* the default skin is used.
* This action act for all layouts. A Tile's attribute (skinLayout) is used as a key to
* know which layouts is concerned.
*/
public class LayoutSwitchAction extends TilesAction
{
/** debug flag */
public static boolean debug = true;
/** Tile's attribute containing layout key */
public static final String LAYOUT_ATTRIBUTE = "layout.attribute";
/** Tile attribute containing name used to store user settings in session context */
public static String USER_SETTINGS_NAME_ATTRIBUTE = "userSettingsName";
/** Default name used to store settings in session context */
public static String DEFAULT_USER_SETTINGS_NAME = "examples.tiles.skin.SELECTED_DEFINITION";
/** Name of catalog in application context */
public static final String CATALOG_NAME = "examples.tiles.skin.CATALOG_NAME";
/** Default name used to store menu catalog in application scope */
public static String DEFAULT_CATALOG_NAME = "tiles.examples.skin.layoutCatalog";
/** Tile attribute containing name used to store menu catalog in application scope */
public static String CATALOG_NAME_ATTRIBUTE = "catalogName";
/** Tile attribute containing name of the settings definition used to initialize catalog */
public static final String CATALOG_SETTING_ATTRIBUTE = "catalogSettings";
/**
* Process the specified HTTP request, and create the corresponding HTTP
* response (or forward to another web component that will create it).
* Return an <code>ActionForward</code> instance describing where and how
* control should be forwarded, or <code>null</code> if the response has
* already been completed.
* This method should be implemented by subclasses.
*
* @param context The current Tile context, containing Tile attributes
* @param mapping The ActionMapping used to select this instance
* @param actionForm The optional ActionForm bean for this request (if any)
* @param request The HTTP request we are processing
* @param response The HTTP response we are creating
*
* @exception IOException if an input/output error occurs
* @exception ServletException if a servlet exception occurs
*/
public ActionForward perform( ComponentContext context,
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response)
throws IOException, ServletException
{
if(debug)
System.out.println( "EnterLayoutSwitchAction" );
// Get attribute value indicating which layout we want
String layoutKey = (String)context.getAttribute( LAYOUT_ATTRIBUTE );
if(layoutKey==null)
throw new ServletException( "Error - CustomSkinAction : attribute '"
+ LAYOUT_ATTRIBUTE
+ "' not found in Tile's attributes. Need it to select appropriate layout" );
// Get user current skin
ComponentDefinition definition = getCurrentDefinition( context, request, getServlet().getServletContext() );
// get requested layout from definition
String layout = (String)definition.getAttribute(layoutKey);
if(layout==null)
throw new ServletException( "Error - CustomSkinAction : no layout defined for key '"
+ layoutKey
+ "' in currently selected skin '"
+ getUserSetting(context, request ) + "'." );
// set path to forward to
// Not very nice solution, need to improve it
/*
ComponentDefinition forwarDefinition = new ComponentDefinition( "", layout, new HashMap() );
DefinitionsUtil.setActionDefinition( request, forwarDefinition );
*/
if(debug)
System.out.println( "Switch to : " + layout );
RequestDispatcher rd = getServlet().getServletContext().getRequestDispatcher( layout );
if(rd==null)
throw new ServletException( "LayoutSwitch error : Can't find layout '"
+ layout + "'." );
rd.include(request, response);
if(debug)
System.out.println( "Exit LayoutSwitchAction" );
return null;
}
/**
* Retrieve key associated to user.
* This key denote a definition in catalog.
* Return user selected key, or "default" if none is set.
*/
public static String getUserSetting( ComponentContext context, HttpServletRequest request )
{
HttpSession session = request.getSession( false );
if( session == null )
return null;
// Retrieve attribute name used to store settings.
String userSettingsName = (String)context.getAttribute( USER_SETTINGS_NAME_ATTRIBUTE );
if( userSettingsName == null )
userSettingsName = DEFAULT_USER_SETTINGS_NAME;
return (String)session.getAttribute(userSettingsName);
}
/**
* Set user setting value.
* This key denote a definition in catalog.
* Return user selected key, or "default" if none is set.
*/
public static void setUserSetting( ComponentContext context, HttpServletRequest request, String setting )
{
HttpSession session = request.getSession();
// Retrieve attribute name used to store settings.
String userSettingsName = (String)context.getAttribute( USER_SETTINGS_NAME_ATTRIBUTE );
if( userSettingsName == null )
userSettingsName = DEFAULT_USER_SETTINGS_NAME;
session.setAttribute(userSettingsName, setting);
}
/**
* Get currently selected skin definition.
*/
public static ComponentDefinition getCurrentDefinition( ComponentContext context, HttpServletRequest request, ServletContext servletContext )
throws ServletException
{
// Get selected key
String selected = getUserSetting(context, request);
DefinitionCatalog catalog = getCatalog( context, request, servletContext);
ComponentDefinition definition = (ComponentDefinition)catalog.get( selected );
if( definition == null )
definition = (ComponentDefinition)catalog.getDefault();
return definition;
}
/**
* Get catalog of available skins.
*/
public static DefinitionCatalog getCatalog( ComponentContext context, HttpServletRequest request, ServletContext servletContext )
throws ServletException
{
// Retrieve name used to store catalog in application context.
// If not found, use default name
String catalogName = (String)context.getAttribute( CATALOG_NAME_ATTRIBUTE );
if(catalogName == null)
catalogName = DEFAULT_CATALOG_NAME;
if(debug)
System.out.println( "Catalog name=" + catalogName );
try
{
DefinitionCatalog catalog = (DefinitionCatalog)servletContext.getAttribute( catalogName );
if(catalog == null)
{ // create catalog
if(debug)
System.out.println( "Create catalog" );
String catalogSettings = (String)context.getAttribute( CATALOG_SETTING_ATTRIBUTE );
if(catalogSettings == null)
throw new ServletException( "Error - CustomSkinAction : attribute '"
+ CATALOG_SETTING_ATTRIBUTE
+ "' not found in Tile's attributes. Need it to initialize catalog" );
catalog = new DefinitionCatalog( catalogSettings, request, servletContext );
if(debug)
System.out.println( "Catalog created" );
servletContext.setAttribute( catalogName, catalog );
} // end if
return catalog;
}
catch(DefinitionsFactoryException ex )
{
if(debug)
System.out.println( "Exception : " + ex.getMessage() );
throw new ServletException( ex.getMessage() );
}
}
}