/*
    * 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.custom.updateactionlistener;
  
  import java.io.IOException;
  
  import javax.el.ELException;
  import javax.faces.FacesException;
  import javax.faces.application.Application;
  import javax.faces.component.ActionSource;
  import javax.faces.component.UIComponent;
  import javax.faces.convert.Converter;
  import javax.faces.event.ActionListener;
  import javax.faces.view.facelets.ComponentConfig;
  import javax.faces.view.facelets.FaceletContext;
  import javax.faces.view.facelets.FaceletException;
  import javax.faces.view.facelets.TagAttribute;
  import javax.faces.view.facelets.TagConfig;
  import javax.faces.view.facelets.TagHandler;
  import javax.faces.webapp.UIComponentTag;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  /**
   * Tag handler for the Tomahawk UpdateActionListener tag
   * 
   * @since 1.1.7
   * @author arobinson74
   */
  public class UpdateActionListenerTagHandler extends TagHandler
  {
      private static Log logger = LogFactory
              .getLog(UpdateActionListenerTagHandler.class);
  
      private TagAttribute converterAttr;
      private TagAttribute propertyAttr;
      private TagAttribute valueAttr;
  
      /**
       * @param config
       */
      public UpdateActionListenerTagHandler(ComponentConfig config)
      {
          this((TagConfig) config);
      }
  
      /**
       * @param config
       */
      public UpdateActionListenerTagHandler(TagConfig config)
      {
          super(config);
          valueAttr = getRequiredAttribute("value");
          propertyAttr = getRequiredAttribute("property");
          converterAttr = getAttribute("converter");
      }
  
      /**
       * @see com.sun.facelets.FaceletHandler#apply(com.sun.facelets.FaceletContext, javax.faces.component.UIComponent)
       */
      public void apply(FaceletContext ctx, UIComponent parent)
              throws IOException, FacesException, FaceletException, ELException
      {
          logger.debug("Apply called. Component: " + parent);
          ActionSource actionSource = (ActionSource) parent;
  
          if (sourceHasProperty(actionSource))
              return;
  
          UpdateActionListener al = new UpdateActionListener();
  
          Application app = ctx.getFacesContext().getApplication();
          if (converterAttr != null)
          {
              Converter converter = app.createConverter(converterAttr
                      .getValue(ctx));
              al.setConverter(converter);
          }
  
          String value = valueAttr.getValue();
          if (UIComponentTag.isValueReference(value))
              al.setValueBinding(app.createValueBinding(valueAttr.getValue()));
         else
             al.setValue(value);
 
         al.setPropertyBinding(app.createValueBinding(propertyAttr.getValue()));
 
         actionSource.addActionListener(al);
     }
 
     private boolean sourceHasProperty(ActionSource source)
     {
         ActionListener[] listeners = source.getActionListeners();
         for (int i = 0; i < listeners.length; i++)
         {
             ActionListener listener = listeners[i];
             if (listener instanceof UpdateActionListener == false)
                 continue;
             UpdateActionListener al = (UpdateActionListener) listener;
             if (al.getPropertyBinding().getExpressionString().equals(
                     this.propertyAttr.getValue()))
             {
                 logger.debug("Action listener already has a listener for "
                         + this.propertyAttr.getValue());
                 return true;
             }
         }
         logger.debug("Action listener for property is not present. Property: "
                 + this.propertyAttr.getValue());
         return false;
     }
 }