/*
    * $Id: AbstractBaseAttributeRenderer.java 791161 2009-07-04 18:53:36Z 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.renderer.impl;
  
  import java.io.IOException;
  import java.util.Iterator;
  import java.util.Set;
  
  import org.apache.tiles.Attribute;
  import org.apache.tiles.TilesApplicationContext;
  import org.apache.tiles.awareness.TilesApplicationContextAware;
  import org.apache.tiles.awareness.TilesRequestContextFactoryAware;
  import org.apache.tiles.context.TilesRequestContext;
  import org.apache.tiles.context.TilesRequestContextFactory;
  import org.apache.tiles.evaluator.AttributeEvaluator;
  import org.apache.tiles.evaluator.AttributeEvaluatorFactory;
  import org.apache.tiles.evaluator.AttributeEvaluatorFactoryAware;
  import org.apache.tiles.renderer.AttributeRenderer;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /***
   * Base abstract class that manages authorization to display the attribute.
   *
   * @version $Rev: 791161 $ $Date: 2009-07-04 20:53:36 +0200 (sab, 04 lug 2009) $
   * @since 2.1.0
   */
  public abstract class AbstractBaseAttributeRenderer implements
          AttributeRenderer, TilesRequestContextFactoryAware,
          TilesApplicationContextAware, AttributeEvaluatorFactoryAware {
  
      /***
       * The logging object.
       */
      private final Logger log = LoggerFactory
              .getLogger(AbstractBaseAttributeRenderer.class);
  
      /***
       * The Tiles request context factory.
       *
       * @since 2.1.1
       */
      protected TilesRequestContextFactory contextFactory;
  
      /***
       * The Tiles application context.
       *
       * @since 2.1.0
       */
      protected TilesApplicationContext applicationContext;
  
      /***
       * The attribute evaluator factory.
       *
       * @since 2.2.0
       */
      protected AttributeEvaluatorFactory attributeEvaluatorFactory;
  
      /*** {@inheritDoc} */
      public void setRequestContextFactory(TilesRequestContextFactory contextFactory) {
          this.contextFactory = contextFactory;
      }
  
      /*** {@inheritDoc} */
      public void setApplicationContext(TilesApplicationContext applicationContext) {
          this.applicationContext = applicationContext;
      }
  
      /*** {@inheritDoc} */
      public void setAttributeEvaluatorFactory(AttributeEvaluatorFactory attributeEvaluatorFactory) {
          this.attributeEvaluatorFactory = attributeEvaluatorFactory;
      }
  
      /*** {@inheritDoc} */
      public void render(Attribute attribute, TilesRequestContext request) throws IOException {
          if (!isPermitted(request, attribute.getRoles())) {
              if (log.isDebugEnabled()) {
                  log.debug("Access to attribute denied.  User not in role '"
                          + attribute.getRoles() + "'");
              }
              return;
         }
 
         AttributeEvaluator evaluator = attributeEvaluatorFactory
                 .getAttributeEvaluator(attribute);
         Object value = evaluator.evaluate(attribute, request);
 
         write(value, attribute, request);
     }
 
     /***
      * Implement this method knowing that the attribute won't be null and it
      * will be authorized.
      * @param value The value of the attribute to be rendered.
      * @param attribute The attribute to render.
      * @param request The Tiles request object.
      * @throws IOException If something goes wrong during rendition.
      * @since 2.1.2
      */
     public abstract void write(Object value, Attribute attribute,
             TilesRequestContext request)
             throws IOException;
 
     /***
      * Creates a Tiles request context from request items.
      *
      * @param requestItems The request items.
      * @return The created Tiles request context.
      * @since 2.1.0
      */
     protected TilesRequestContext getRequestContext(Object... requestItems) {
         return contextFactory.createRequestContext(applicationContext,
                 requestItems);
     }
 
     /***
      * Checks if the current user is in one of the comma-separated roles
      * specified in the <code>role</code> parameter.
      *
      * @param request The request context.
      * @param roles The list of roles.
      * @return <code>true</code> if the current user is in one of those roles.
      * @since 2.1.0
      */
     protected boolean isPermitted(TilesRequestContext request, Set<String> roles) {
         if (roles == null || roles.isEmpty()) {
             return true;
         }
 
         boolean retValue = false;
 
         for (Iterator<String> roleIt = roles.iterator(); roleIt.hasNext()
                 && !retValue;) {
             retValue = request.isUserInRole(roleIt.next());
         }
 
         return retValue;
     }
 }