/*
    * 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.el.unified;
  
  import java.lang.reflect.InvocationTargetException;
  import java.lang.reflect.Method;
  import java.util.ArrayList;
  import java.util.List;
  
  import javax.el.ArrayELResolver;
  import javax.el.BeanELResolver;
  import javax.el.CompositeELResolver;
  import javax.el.ELResolver;
  import javax.el.ExpressionFactory;
  import javax.el.ListELResolver;
  import javax.el.MapELResolver;
  import javax.el.ResourceBundleELResolver;
  import javax.faces.context.FacesContext;
  
  import org.apache.myfaces.config.RuntimeConfig;
  import org.apache.myfaces.el.FlashELResolver;
  import org.apache.myfaces.el.unified.resolver.CompositeComponentELResolver;
  import org.apache.myfaces.el.unified.resolver.FacesCompositeELResolver.Scope;
  import org.apache.myfaces.el.unified.resolver.ImportHandlerResolver;
  import org.apache.myfaces.el.unified.resolver.ManagedBeanResolver;
  import org.apache.myfaces.el.unified.resolver.ResourceBundleResolver;
  import org.apache.myfaces.el.unified.resolver.ResourceResolver;
  import org.apache.myfaces.el.unified.resolver.ScopedAttributeResolver;
  import org.apache.myfaces.el.unified.resolver.implicitobject.ImplicitObjectResolver;
  import org.apache.myfaces.shared.config.MyfacesConfig;
  import org.apache.myfaces.shared.util.ClassUtils;
  
  /**
   * Create the el resolver for faces. see 1.2 spec section 5.6.2
   * 
   * @author Mathias Broekelmann (latest modification by $Author$)
   * @version $Revision$ $Date$
   */
  public class ResolverBuilderForFaces extends ResolverBuilderBase implements ELResolverBuilder
  {
      private static final Class STATIC_FIELD_EL_RESOLVER_CLASS;
      private static final Method GET_STREAM_EL_RESOLVER_METHOD;
      
      static
      {
          Class staticFieldELResolverClass = null;
          Method getStreamELResolverMethod = null;
          try
          {
              staticFieldELResolverClass = ClassUtils.classForName("javax.el.StaticFieldELResolver");
              getStreamELResolverMethod = ExpressionFactory.class.getMethod("getStreamELResolver");
          }
          catch (NoSuchMethodException ex)
          {
              //No op
          }
          catch (SecurityException ex)
          {
              //No op
          }
          catch (ClassNotFoundException ex)
          {
              //No op
          }
          STATIC_FIELD_EL_RESOLVER_CLASS = staticFieldELResolverClass;
          GET_STREAM_EL_RESOLVER_METHOD = getStreamELResolverMethod;
      }
      
      public ResolverBuilderForFaces(RuntimeConfig config)
      {
          super(config);
      }
  
      public void build(CompositeELResolver compositeElResolver)
      {
          // add the ELResolvers to a List first to be able to sort them
          List<ELResolver> list = new ArrayList<ELResolver>();
          
          list.add(ImplicitObjectResolver.makeResolverForFaces());
          list.add(new CompositeComponentELResolver());
  
          addFromRuntimeConfig(list);
  
         //Flash object is instanceof Map, so it is necessary to resolve
         //before MapELResolver. Better to put this one before
         list.add(new FlashELResolver());
         list.add(new ManagedBeanResolver());
         list.add(new ResourceResolver());
         list.add(new ResourceBundleELResolver());
         list.add(new ResourceBundleResolver());
         
         if (STATIC_FIELD_EL_RESOLVER_CLASS != null &&
             GET_STREAM_EL_RESOLVER_METHOD != null)
         {
             try
             {
                 ELResolver streamElResolver = (ELResolver) GET_STREAM_EL_RESOLVER_METHOD.invoke(
                         getRuntimeConfig().getExpressionFactory());
                 if (streamElResolver != null)
                 {
                     // By default return null, but in a EL 3 implementation it should be there,
                     // this is just to avoid exceptions in junit testing
                     list.add(streamElResolver);
                 }
                 list.add((ELResolver) STATIC_FIELD_EL_RESOLVER_CLASS.newInstance());
             } 
             catch (IllegalAccessException ex)
             {
             }
             catch (IllegalArgumentException ex)
             {
             }
             catch (InvocationTargetException ex)
             {
             }
             catch (InstantiationException ex)
             {
             }
         }
         
         list.add(new MapELResolver());
         list.add(new ListELResolver());
         list.add(new ArrayELResolver());
         list.add(new BeanELResolver());
         
         // give the user a chance to sort the resolvers
         sortELResolvers(list, Scope.Faces);
         
         // give the user a chance to filter the resolvers
         Iterable<ELResolver> filteredELResolvers = filterELResolvers(list, Scope.Faces);
         
         // add the resolvers from the list to the CompositeELResolver
         for (ELResolver resolver : filteredELResolvers)
         {
             compositeElResolver.add(resolver);
         }
         
         // Only add this resolver if the user wants to use the EL ImportHandler
         if (MyfacesConfig.getCurrentInstance(
              FacesContext.getCurrentInstance().getExternalContext()).isSupportEL3ImportHandler())
         {
             compositeElResolver.add(new ImportHandlerResolver());
         }
         
         // the ScopedAttributeResolver has to be the last one in every
         // case, because it always sets propertyResolved to true (per the spec)
         compositeElResolver.add(new ScopedAttributeResolver());
     }
 
 }