/*
    * 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);
  }