/*

  * 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;

 import javax.el.ELContext;

 import javax.el.ELException;

 import javax.el.ValueExpression;

 import javax.faces.application.Application;

 import javax.faces.context.FacesContext;

 import javax.faces.el.EvaluationException;

 import javax.faces.el.VariableResolver;

 import org.apache.myfaces.el.unified.resolver.FacesCompositeELResolver;

 import org.apache.myfaces.el.unified.resolver.FacesCompositeELResolver.Scope;

 /**

  * This variable resolver will be used for legacy variable resolvers which are registered through the faces config. If

  * it is invoked through the faces chain it will use the el resolver of {@link Application#getELResolver()}. If it is

  * invoked through the jsp chain it will create an value expression through {@link Application#getExpressionFactory()}

  * to resolve the variable.

  * 

  * @author Manfred Geiler (latest modification by $Author$)

  * @author Anton Koinov

  * @author Mathias Broekelmann

  * @version $Revision$ $Date$

  */

 @SuppressWarnings("deprecation")

 public final class VariableResolverImpl extends VariableResolver

 {

     @Override

     public Object resolveVariable(final FacesContext context, final String name) throws EvaluationException

     {

         if (context == null)

         {

             throw new NullPointerException("context must not be null");

         }

         if (name == null)

         {

             throw new NullPointerException("name must not be null");

         }

         try

         {

             final Scope scope = getScope(context);

             final ELContext elcontext = context.getELContext();

             final Application application = context.getApplication();

             if (Scope.Faces.equals(scope))

             {

                 return application.getELResolver().getValue(elcontext, null, name);

             }

             else if (Scope.JSP.equals(scope))

             {

                 ValueExpression expression = application.getExpressionFactory().createValueExpression(elcontext,

                         "#{" + name + "}", Object.class);

                 return expression.getValue(elcontext);

             }

             else

             {

                 throw new IllegalStateException("unknown scope defined: " + scope);

             }

         }

         catch (ELException e)

         {

             throw new EvaluationException(e.getMessage(), e);

         }

     }

     protected Scope getScope(final FacesContext context)

     {

         return (Scope) context.getAttributes().get(FacesCompositeELResolver.SCOPE);

     }

 }