/*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you under the Apache License, Version 2.0 (the

  * "License"); you may not use this file except in compliance

  * with the License.  You may obtain a copy of the License at

  *

  *   http://www.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing,

  * software distributed under the License is distributed on an

  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY

  * KIND, either express or implied.  See the License for the

  * specific language governing permissions and limitations

  * under the License.

  */

 package org.apache.myfaces.spi;

 import java.security.AccessController;

 import java.security.PrivilegedActionException;

 import java.security.PrivilegedExceptionAction;

 import javax.faces.FacesException;

 import javax.faces.context.ExternalContext;

 import org.apache.myfaces.spi.impl.DefaultFacesConfigResourceProviderFactory;

 import org.apache.myfaces.spi.impl.SpiUtils;

 /**

  * Factory that provide FacesConfigResourceProvider instances

  * 

  * @since 2.0.2

  * @author Leonardo Uribe

  */

 public abstract class FacesConfigResourceProviderFactory

 {

     protected static final String FACTORY_DEFAULT = DefaultFacesConfigResourceProviderFactory.class.getName();

     private static final String FACTORY_KEY = FacesConfigResourceProviderFactory.class.getName();

     public static FacesConfigResourceProviderFactory getFacesConfigResourceProviderFactory(ExternalContext ctx)

     {

         FacesConfigResourceProviderFactory instance

                 = (FacesConfigResourceProviderFactory) ctx.getApplicationMap().get(FACTORY_KEY);

         if (instance != null)

         {

             return instance;

         }

         FacesConfigResourceProviderFactory lpf = null;

         try

         {

             if (System.getSecurityManager() != null)

             {

                 final ExternalContext ectx = ctx;

                 lpf = (FacesConfigResourceProviderFactory)

                         AccessController.doPrivileged(new PrivilegedExceptionAction<Object>()

                         {

                             public Object run() throws PrivilegedActionException

                             {

                                 return SpiUtils.build(ectx,

                                         FacesConfigResourceProviderFactory.class,

                                         FACTORY_DEFAULT);

                             }

                         });

             }

             else

             {

                 lpf = (FacesConfigResourceProviderFactory)

                         SpiUtils.build(ctx, FacesConfigResourceProviderFactory.class, FACTORY_DEFAULT);

             }

         }

         catch (PrivilegedActionException pae)

         {

             throw new FacesException(pae);

         }

         if (lpf != null)

         {

             setFacesConfigResourceProviderFactory(ctx, lpf);

         }

         return lpf;

     }

     public static void setFacesConfigResourceProviderFactory(ExternalContext ctx,

                                                              FacesConfigResourceProviderFactory instance)

     {

         ctx.getApplicationMap().put(FACTORY_KEY, instance);

     }

     public abstract FacesConfigResourceProvider createFacesConfigResourceProvider(ExternalContext externalContext);

 }