/*
    * 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.view.facelets.tag.composite;
  
  import java.beans.PropertyDescriptor;
  
  import javax.el.ValueExpression;
  import javax.faces.component.UIComponent;
  import javax.faces.view.facelets.FaceletContext;
  import javax.faces.view.facelets.MetaRule;
  import javax.faces.view.facelets.Metadata;
  import javax.faces.view.facelets.MetadataTarget;
  import javax.faces.view.facelets.TagAttribute;
  
  /**
   * Rule used to wire ValueExpressions retrieved by ViewDeclarationLanguage.retargetMethodExpressions 
   * 
   * @author Leonardo Uribe (latest modification by $Author$)
   * @version $Revision$ $Date$
   */
  final class RetargetMethodExpressionRule extends MetaRule
  {
      final static class RetargetValueExpressionMapper extends Metadata
      {
          private final TagAttribute _attr;
          
          private final String _name;
  
          public RetargetValueExpressionMapper(TagAttribute attr, String name)
          {
              this._attr = attr;
              this._name = name;
          }
  
          public void applyMetadata(FaceletContext ctx, Object instance)
          {
              ValueExpression expr = _attr.getValueExpression(ctx, Object.class);
              ((UIComponent) instance).getAttributes().put(_name, expr);
          }
      }
  
      public final static RetargetMethodExpressionRule INSTANCE = new RetargetMethodExpressionRule();
  
      public RetargetMethodExpressionRule()
      {
          super();
      }
  
      public Metadata applyRule(String name, TagAttribute attribute, MetadataTarget meta)
      {
          // ViewDeclarationLanguage.retargetMethodExpressions only works when a method-signature 
          // is defined, so we just have to apply this rule on that case. 
          if ("action".equals(name) || 
              "actionListener".equals(name) ||
              "validator".equals(name) ||
              "valueChangeListener".equals(name))
          {
              return new RetargetValueExpressionMapper(attribute, name);
          }
          else
          {
              PropertyDescriptor propertyDescriptor = meta.getProperty(name);
              //Type takes precedence over method-signature
              if (propertyDescriptor != null && 
                      propertyDescriptor.getValue("type") == null)
              {
                  ValueExpression methodSignatureExpression = 
                      (ValueExpression) propertyDescriptor.getValue("method-signature");
                  
                  if (methodSignatureExpression != null)
                  {
                      return new RetargetValueExpressionMapper(attribute, name);
                  }
                  
                  ValueExpression targetAttributeNameVE = 
                      (ValueExpression)propertyDescriptor.getValue("targetAttributeName");
                  if (targetAttributeNameVE != null)
                  {
                      return new RetargetValueExpressionMapper(attribute, name);
                  }
                  
                  //if there is a targets declaration, is a retarget without doubt
                  ValueExpression targets = 
                     (ValueExpression)propertyDescriptor.getValue("targets");
                 
                 if (targets != null)
                 {
                     return new RetargetValueExpressionMapper(attribute, name);
                 }
             }
         }
         return null;
     }
 }