/*
    * 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.tabbedpane;
  
  import javax.faces.component.UIComponent;
  import javax.faces.context.FacesContext;
  import javax.faces.el.ValueBinding;
  import javax.faces.webapp.UIComponentTag;
  import javax.servlet.jsp.JspException;
  import javax.servlet.jsp.tagext.Tag;
  import javax.servlet.jsp.tagext.TagSupport;
  
  import org.apache.myfaces.shared_tomahawk.util.ClassUtils;
  
  
  /**
   * Tag to add a tab change listeners to a {@link org.apache.myfaces.custom.tabbedpane.HtmlPanelTabbedPane}
   *
   * @JSFJspTag
   *   name="t:tabChangeListener"
   *   bodyContent="empty"
   *   tagHandler = "org.apache.myfaces.custom.tabbedpane.TabChangeListenerTagHandler"
   *   
   * @author <a href="mailto:oliver@rossmueller.com">Oliver Rossmueller</a>
   * @version $Revision: 692184 $ $Date: 2008-09-04 13:21:52 -0500 (Thu, 04 Sep 2008) $
   */
  public class TabChangeListenerTag extends TagSupport
  {
      private static final long serialVersionUID = -6903749011638483023L;
      private String type = null;
  
  
      public TabChangeListenerTag()
      {
      }
  
      /**
       * @JSFJspAttribute
       *   required = "true"
       */
      public void setType(String type)
      {
          this.type = type;
      }
  
  
      public int doStartTag() throws JspException
      {
          if (type == null)
          {
              throw new JspException("type attribute not set");
          }
  
          //Find parent UIComponentTag
          UIComponentTag componentTag = UIComponentTag.getParentUIComponentTag(pageContext);
          if (componentTag == null)
          {
              throw new JspException("TabChangeListenerTag has no UIComponentTag ancestor");
          }
  
          if (componentTag.getCreated())
          {
              //Component was just created, so we add the Listener
              UIComponent component = componentTag.getComponentInstance();
              if (component instanceof HtmlPanelTabbedPane)
              {
                  Object listenerRef = type;
                  if (UIComponentTag.isValueReference(type))
                  {
                      FacesContext facesContext = FacesContext.getCurrentInstance();
                      ValueBinding valueBinding = facesContext.getApplication().createValueBinding(type);
                      listenerRef = valueBinding.getValue(facesContext);
                  }
  
                  if(listenerRef instanceof String)
                  {
                      String className = (String) listenerRef;
                      TabChangeListener listener = (TabChangeListener) ClassUtils.newInstance(className);
                      ((HtmlPanelTabbedPane) component).addTabChangeListener(listener);
                  }
                  else if(listenerRef instanceof TabChangeListener)
                  {
                      TabChangeListener listener = (TabChangeListener) listenerRef;
                     ((HtmlPanelTabbedPane) component).addTabChangeListener(listener);
 
                 }
                 else
                     throw new JspException("type is neither a 'String' nor a value-binding to a 'String' or a 'TabChangeListener' instance.");
             }
             else
             {
                 throw new JspException("Component " + component.getId() + " is no HtmlPanelTabbedPane");
             }
         }
 
         return Tag.SKIP_BODY;
     }
 }