/*
    * 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 javax.faces.FacesException;
  import javax.faces.component.StateHolder;
  import javax.faces.component.UIComponentBase;
  import javax.faces.component.ValueHolder;
  import javax.faces.context.FacesContext;
  import javax.faces.convert.Converter;
  import javax.faces.el.ValueBinding;
  import javax.faces.event.AbortProcessingException;
  import javax.faces.event.ActionEvent;
  import javax.faces.event.ActionListener;
  
  /**
   * Set an arbitrary property on a managed bean when an "action" component is
   * selected by the user.
   * <p>
   * An instance of this listener type can be attached to any UIComponent which
   * is an ActionSource (eg a link or button). When the associated component
   * fires its action event, this listener will read the value specified by
   * attribute "value" and assign it to the property specified by attribute
   * "property". The value attribute may be a literal value or may be a
   * value-binding; the property is always expected to be a value-binding.
   * <p>
   * An optional Converter may be associated with this listener, and if present
   * will be invoked to convert the value to the datatype expected by the
   * target property. When no converter is available, a default one will be
   * retrieved from the Application object.
   * <p>
   * A common use for this listener is to attach it to an HtmlCommandLink
   * component, storing some constant value into a managed bean property.
   * After the navigation associated with that link is done, components in
   * the new view can look at that property to determine which link was
   * clicked.
   * <p>
   * Both the fetching of "value" and the updating of "property" occur in
   * the invoke-application phase unless "immediate" is set on the ActionSource
   * component in which case they both occur in the apply-request-values phase.
   * The update is guaranteed to occur before the invocation of the method
   * specified by attribute "action" on the ActionSource (because all
   * actionListeners are executed before the action attribute).
   * <p>
   * JSF 1.2 introduces a "setPropertyActionListener" with the same functionality like this.
   * <p>
   * @author Manfred Geiler (latest modification by $Author: grantsmith $)
   * @version $Revision: 472638 $ $Date: 2006-11-08 15:54:13 -0500 (Wed, 08 Nov 2006) $
   */
  public class UpdateActionListener
          implements ActionListener, ValueHolder, StateHolder
  {
      //private static final Log log = LogFactory.getLog(UpdateActionListener.class);
  
      private ValueBinding _propertyBinding;
      private Object _value;
      private ValueBinding _valueBinding;
      private Converter _converter;
  
      public void setPropertyBinding(ValueBinding propertyBinding)
      {
          _propertyBinding = propertyBinding;
      }
  
      public ValueBinding getPropertyBinding()
      {
          return _propertyBinding;
      }
  
      public void setValue(Object value)
      {
          _value = value;
      }
  
      public Object getValue()
      {
          if (_value != null) return _value;
          ValueBinding vb = getValueBinding();
          if (vb != null)
          {
              FacesContext context = FacesContext.getCurrentInstance();
              return vb.getValue(context);
          }
         return null;
     }
 
     public Object getLocalValue()
     {
         return _value;
     }
 
     public ValueBinding getValueBinding()
     {
         return _valueBinding;
     }
 
     public void setValueBinding(ValueBinding valueBinding)
     {
         _valueBinding = valueBinding;
     }
 
     public Converter getConverter()
     {
         return _converter;
     }
 
     public void setConverter(Converter converter)
     {
         _converter = converter;
     }
 
     public void processAction(ActionEvent actionEvent) throws AbortProcessingException
     {
         FacesContext context = FacesContext.getCurrentInstance();
         ValueBinding updateBinding = getPropertyBinding();
         Object v = getValue();
         if (v != null &&
             v instanceof String)
         {
             Class type = updateBinding.getType(context);
             if (!type.equals(String.class) && ! type.equals(Object.class))
             {
                 String converterErrorMessage = "No Converter registered with UpdateActionListener and no appropriate standard converter found. Needed to convert String to " + type.getName();
                 Converter converter = getConverter();
                 if (converter == null)
                 {
                     try
                     {
                         converter = context.getApplication().createConverter(type);
                     }
                     catch (Exception e)
                     {
                         throw new FacesException(converterErrorMessage, e);
                     }
                 }
                 if (null == converter)
                 {
                     throw new FacesException(converterErrorMessage);
                 }
                 v = converter.getAsObject(context, context.getViewRoot(), (String)v);
             }
         }
         updateBinding.setValue(context, v);
     }
 
 
 
     // StateHolder methods
 
     public Object saveState(FacesContext context)
     {
         Object values[] = new Object[4];
         values[0] = UIComponentBase.saveAttachedState(context, _propertyBinding);
         values[1] = _value;
         values[2] = UIComponentBase.saveAttachedState(context, _valueBinding);
         values[3] = UIComponentBase.saveAttachedState(context, _converter);
         return ((Object) (values));
     }
 
     public void restoreState(FacesContext context, Object state)
     {
         Object values[] = (Object[])state;
         _propertyBinding = (ValueBinding)UIComponentBase.restoreAttachedState(context, values[0]);
         _value = values[1];
         _valueBinding = (ValueBinding)UIComponentBase.restoreAttachedState(context, values[2]);;
         _converter = (Converter)UIComponentBase.restoreAttachedState(context, values[3]);;
     }
 
     public boolean isTransient()
     {
         return false;
     }
 
     public void setTransient(boolean newTransientValue)
     {
         if (newTransientValue == true) throw new IllegalArgumentException();
     }
 
 }