/*
    * 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.taglib.core;
  
  import javax.el.ELContext;
  import javax.el.ValueExpression;
  import javax.faces.application.Application;
  import javax.faces.application.FacesMessage;
  import javax.faces.component.StateHolder;
  import javax.faces.component.UIComponent;
  import javax.faces.context.FacesContext;
  import javax.faces.validator.Validator;
  import javax.faces.validator.ValidatorException;
  
  /**
   * This class is used in conjunction with ValidatorImplTag. 
   * 
   * When a tag like this is in a jsp page:
   * 
   * <f:validator binding="#{mybean}"/>
   *  
   *  or
   *  
   * <f:validator validatorId="#{'anyid'}" binding="#{mybean}"/>
   * 
   * The value of mybean could be already on the context, so this
   * converter avoid creating a new variable and use the previous one.
   *
   * @author Leonardo Uribe (latest modification by $Author$)
   * @version $Revision$ $Date$
   *
   */
  public class DelegateValidator implements Validator, StateHolder
  {
  
      private ValueExpression _validatorId;
      private ValueExpression _binding;
      private String _validatorIdString = null;
      
      public DelegateValidator()
      {
          
      }
      
      public DelegateValidator(ValueExpression id, ValueExpression binding, String converterIdString)
      {
          super();
          _validatorId = id;
          _binding = binding;
          _validatorIdString = converterIdString;
      }
  
      public boolean isTransient()
      {
          return false;
      }
  
      public void restoreState(FacesContext facesContext, Object state)
      {
          Object[] values = (Object[]) state;
          _validatorId = (ValueExpression) values[0];
          _binding = (ValueExpression) values[1];
          _validatorIdString = (String) values[2];
      }
  
      public Object saveState(FacesContext facesContext)
      {
          Object[] values = new Object[3];
          values[0] = _validatorId;
          values[1] = _binding;
          values[2] = _validatorIdString;
          return values;
      }
  
      public void setTransient(boolean arg0)
      {
          // Do nothing        
      }
  
      private Validator _getDelegate()
      {
          return _createValidator();
      }
 
     private Validator _createValidator()
     {
         FacesContext facesContext = FacesContext.getCurrentInstance();
         ELContext elContext = facesContext.getELContext();
         if (null != _binding)
         {
             Object validator;
             try
             {
                 validator = _binding.getValue(elContext);
             }
             catch (Exception e)
             {
                 throw new ValidatorException(new FacesMessage("Error while creating the Validator"), e);
             }
             if (validator instanceof Validator)
             {
                 return (Validator) validator;
             }
         }
         Application application = facesContext.getApplication();
         Validator validator = null;
         try
         {
             // first check if an ValidatorId was set by a method
             if (null != _validatorIdString)
             {
                 validator = application.createValidator(_validatorIdString);
             }
             else if (null != _validatorId)
             {
                 String validatorId = (String) _validatorId.getValue(elContext);
                 validator = application.createValidator(validatorId);
             }
         }
         catch (Exception e)
         {
             throw new ValidatorException(new FacesMessage("Error while creating the Validator"), e);
         }
 
         if (null != validator)
         {
             if (null != _binding)
             {
                 _binding.setValue(elContext, validator);
             }
             return validator;
         }
         throw new ValidatorException(new FacesMessage("validatorId and/or binding must be specified"));
     }
 
     public void validate(FacesContext facesContext, UIComponent component, Object value)
             throws ValidatorException
     {
         _getDelegate().validate(facesContext, component, value);
     }
 
 }