/*
    * 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;
  
  import java.lang.reflect.InvocationTargetException;
  import java.lang.reflect.Method;
  
  import javax.el.MethodExpression;
  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;
  import javax.faces.view.facelets.TagAttributeException;
  
  /**
   * Optional Rule for binding Method[Binding|Expression] properties
   * 
   * @author Mike Kienenberger
   * @author Jacob Hookom
   */
  public final class MethodRule extends MetaRule
  {
  
      private final String methodName;
  
      private final Class<?> returnTypeClass;
  
      private final Class<?>[] params;
  
      public MethodRule(String methodName, Class<?> returnTypeClass, Class<?>[] params)
      {
          this.methodName = methodName;
          this.returnTypeClass = returnTypeClass;
          this.params = params;
      }
  
      public Metadata applyRule(String name, TagAttribute attribute, MetadataTarget meta)
      {
          if (false == name.equals(this.methodName))
          {
              return null;
          }
  
          if (MethodExpression.class.equals(meta.getPropertyType(name)))
          {
              Method method = meta.getWriteMethod(name);
              if (method != null)
              {
                  return new MethodExpressionMetadata(method, attribute, this.returnTypeClass, this.params);
              }
          }
  
          return null;
      }
  
      private class MethodExpressionMetadata extends Metadata
      {
          private final Method _method;
  
          private final TagAttribute _attribute;
  
          private Class<?>[] _paramList;
  
          private Class<?> _returnType;
  
          public MethodExpressionMetadata(Method method, TagAttribute attribute, Class<?> returnType, 
                                          Class<?>[] paramList)
          {
              _method = method;
              _attribute = attribute;
              _paramList = paramList;
              _returnType = returnType;
          }
  
          public void applyMetadata(FaceletContext ctx, Object instance)
          {
              MethodExpression expr = _attribute.getMethodExpression(ctx, _returnType, _paramList);
  
              try
              {
                  _method.invoke(instance, new Object[] { expr });
              }
             catch (InvocationTargetException e)
             {
                 throw new TagAttributeException(_attribute, e.getCause());
             }
             catch (Exception e)
             {
                 throw new TagAttributeException(_attribute, e);
             }
         }
     }
 }