/*
    * $Id: TilesContextVariableResolverFactory.java 1049688 2010-12-15 20:15:41Z apetrelli $
    *
    * 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.tiles.mvel;
  
  import java.beans.PropertyDescriptor;
  import java.lang.reflect.InvocationTargetException;
  import java.lang.reflect.Method;
  
  import org.apache.tiles.context.TilesRequestContextHolder;
  import org.apache.tiles.request.ApplicationContext;
  import org.apache.tiles.request.Request;
  import org.apache.tiles.request.reflect.CannotAccessMethodException;
  import org.apache.tiles.util.CombinedBeanInfo;
  import org.mvel2.integration.VariableResolver;
  
  /**
   * Resolves {@link org.apache.tiles.request.Request} and
   * {@link org.apache.tiles.request.ApplicationContext} properties as variables.
   *
   * @version $Rev: 1049688 $ $Date: 2010-12-16 07:15:41 +1100 (Thu, 16 Dec 2010) $
   * @since 2.2.0
   */
  public class TilesContextVariableResolverFactory extends
          ReadOnlyVariableResolverFactory {
  
      /**
       * Beaninfo about {@link org.apache.tiles.request.Request} and
       * {@link org.apache.tiles.request.ApplicationContext}.
       */
      private CombinedBeanInfo requestBeanInfo = new CombinedBeanInfo(
              Request.class, ApplicationContext.class);
  
      /**
       * Constructor.
       *
       * @param requestHolder The Tiles request holder.
       * @since 2.2.0
       */
      public TilesContextVariableResolverFactory(TilesRequestContextHolder requestHolder) {
          super(requestHolder);
      }
  
      /** {@inheritDoc} */
      public boolean isTarget(String name) {
          return requestBeanInfo.getMappedDescriptors(Request.class).containsKey(
                  name)
                  || requestBeanInfo.getMappedDescriptors(
                          ApplicationContext.class).containsKey(name);
      }
  
      /** {@inheritDoc} */
      @Override
      public VariableResolver createVariableResolver(String name) {
          VariableResolver resolver = null;
          PropertyDescriptor descriptor = requestBeanInfo.getMappedDescriptors(Request.class).get(name);
          if (descriptor != null) {
              resolver = new RequestVariableResolver(name, descriptor);
          } else {
              descriptor = requestBeanInfo.getMappedDescriptors(ApplicationContext.class).get(name);
              if (descriptor != null) {
                  resolver = new ApplicationVariableResolver(name, descriptor);
              }
          }
          return resolver;
      }
  
      /**
       * Resolves a {@link org.apache.tiles.request.Request} property as a variable.
       *
       * @version $Rev: 1049688 $ $Date: 2010-12-16 07:15:41 +1100 (Thu, 16 Dec 2010) $
       * @since 2.2.0
       */
      private class RequestVariableResolver extends ReadOnlyVariableResolver {
  
          /**
           * The property descriptor.
           */
          private PropertyDescriptor descriptor;
  
          /**
          * Constructor.
          *
          * @param name The name of the property.
          * @param descriptor The property descriptor.
          * @since 2.2.0
          */
         public RequestVariableResolver(String name, PropertyDescriptor descriptor) {
             super(name);
             this.descriptor = descriptor;
         }
 
         /** {@inheritDoc} */
         @SuppressWarnings("rawtypes")
         public Class getType() {
             return descriptor.getPropertyType();
         }
 
         /** {@inheritDoc} */
         public Object getValue() {
             Method method = descriptor.getReadMethod();
             try {
                 return method.invoke(requestHolder.getTilesRequestContext());
             } catch (IllegalArgumentException e) {
                 throw new CannotAccessMethodException(
                         "Arguments are wrong for property '"
                                 + descriptor.getName() + "'", e);
             } catch (IllegalAccessException e) {
                 throw new CannotAccessMethodException(
                         "Cannot access getter method for property '"
                                 + descriptor.getName() + "'", e);
             } catch (InvocationTargetException e) {
                 throw new CannotAccessMethodException(
                         "The getter method for property '"
                                 + descriptor.getName() + "' threw an exception",
                         e);
             }
         }
     }
 
     /**
      * Resolves a {@link org.apache.tiles.request.ApplicationContext} property as a
      * variable.
      *
      * @version $Rev: 1049688 $ $Date: 2010-12-16 07:15:41 +1100 (Thu, 16 Dec 2010) $
      * @since 2.2.0
      */
     private class ApplicationVariableResolver extends ReadOnlyVariableResolver {
 
         /**
          * The property descriptor.
          *
          * @since 2.2.0
          */
         private PropertyDescriptor descriptor;
 
         /**
          * Constructor.
          *
          * @param name The name of the property.
          * @param descriptor The property descriptor.
          * @since 2.2.0
          */
         public ApplicationVariableResolver(String name, PropertyDescriptor descriptor) {
             super(name);
             this.descriptor = descriptor;
         }
 
         /** {@inheritDoc} */
         @SuppressWarnings("rawtypes")
         public Class getType() {
             return descriptor.getPropertyType();
         }
 
         /** {@inheritDoc} */
         public Object getValue() {
             Method method = descriptor.getReadMethod();
             try {
                 return method.invoke(requestHolder.getTilesRequestContext()
                         .getApplicationContext());
             } catch (IllegalArgumentException e) {
                 throw new CannotAccessMethodException(
                         "Arguments are wrong for property '"
                                 + descriptor.getName() + "'", e);
             } catch (IllegalAccessException e) {
                 throw new CannotAccessMethodException(
                         "Cannot access getter method for property '"
                                 + descriptor.getName() + "'", e);
             } catch (InvocationTargetException e) {
                 throw new CannotAccessMethodException(
                         "The getter method for property '"
                                 + descriptor.getName() + "' threw an exception",
                         e);
             }
         }
     }
 }