/*
** Luxor - XML User Interface Language (XUL) Toolkit
** Copyright (c) 2001, 2002 by Gerald Bauer
**
** This program is free software.
**
** You may redistribute it and/or modify it under the terms of the GNU
** General Public License as published by the Free Software Foundation.
** Version 2 of the license should be included with this distribution in
** the file LICENSE, as well as License.html. If the license is not
** included with this distribution, you may find a copy at the FSF web
** site at 'www.gnu.org' or 'www.fsf.org', or you may write to the
** Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139 USA.
**
** THIS SOFTWARE IS PROVIDED AS-IS WITHOUT WARRANTY OF ANY KIND,
** NOT EVEN THE IMPLIED WARRANTY OF MERCHANTABILITY. THE AUTHOR
** OF THIS SOFTWARE, ASSUMES _NO_ RESPONSIBILITY FOR ANY
** CONSEQUENCE RESULTING FROM THE USE, MODIFICATION, OR
** REDISTRIBUTION OF THIS SOFTWARE.
**
*/

package luxor.http.loader;

import java.util.*;
import luxor.core.*;
import luxor.http.resource.*;
import luxor.spi.*;
import luxor.status.*;

public class WebResourceManager implements WebResourceLoader
{
   static Logger T = Logger.getLogger( WebResourceManager.class );

   private static WebResourceManager __instance;

   /**
    *  The List of templateLoaders that the Runtime will use to locate the
    *  InputStream source of a template.
    */
   private static ArrayList _resourceLoaders = new ArrayList();

   /**
    *  WebResourceManager is a singleton, don't allow creation of any instances
    *  outside this class.
    */
   private WebResourceManager() { }

   public static WebResourceManager getWebResourceManager()
   {
      if( __instance == null )
         __instance = new WebResourceManager();

      return __instance;
   }

   public WebResource getResource( String name )
   {
      for( int i = 0; i < _resourceLoaders.size(); i++ )
      {
         WebResourceLoader resourceLoader = ( WebResourceLoader ) _resourceLoaders.get( i );
         WebResource res = resourceLoader.getResource( name );
         if( res != null )
            // bingo!
            return res;
      }

      Xul.error( "failed to retrieve resource '" + name + "'" );

      // resource not found
      return new Error404Resource( name );
   }


   public void addResourceLoader( WebResourceLoader newLoader )
   {
      // todo: make this hack for one class more generic

      // remove previous resource loaders with same context
      if( newLoader instanceof FileContextResourceLoader )
      {
         FileContextResourceLoader newCtxLoader = ( FileContextResourceLoader ) newLoader;
         Iterator it = _resourceLoaders.iterator();
         while( it.hasNext() )
         {
            WebResourceLoader loader = ( WebResourceLoader ) it.next();
            if( loader instanceof FileContextResourceLoader )
            {
               FileContextResourceLoader ctxLoader = ( FileContextResourceLoader ) loader;
               if( ctxLoader.getContext().equalsIgnoreCase( newCtxLoader.getContext() ) )
                  it.remove();
            }
         }
      }

      _resourceLoaders.add( newLoader );
   }

}