/*
    * 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.jsf;
  
  import java.io.IOException;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import java.util.logging.Level;
  import java.util.logging.Logger;
  
  import javax.el.ValueExpression;
  import javax.faces.FacesWrapper;
  import javax.faces.application.Application;
  import javax.faces.application.ProjectStage;
  import javax.faces.component.ActionSource;
  import javax.faces.component.EditableValueHolder;
  import javax.faces.component.UIComponent;
  import javax.faces.component.UniqueIdVendor;
  import javax.faces.component.ValueHolder;
  import javax.faces.component.behavior.ClientBehaviorHolder;
  import javax.faces.context.FacesContext;
  import javax.faces.validator.BeanValidator;
  import javax.faces.validator.Validator;
  import javax.faces.view.EditableValueHolderAttachedObjectHandler;
  import javax.faces.view.facelets.ComponentConfig;
  import javax.faces.view.facelets.ComponentHandler;
  import javax.faces.view.facelets.FaceletContext;
  import javax.faces.view.facelets.MetaRuleset;
  import javax.faces.view.facelets.TagAttribute;
  import javax.faces.view.facelets.TagException;
  import javax.faces.view.facelets.TagHandlerDelegate;
  import javax.faces.view.facelets.ValidatorHandler;
  
  import org.apache.myfaces.util.ExternalSpecifications;
  import org.apache.myfaces.view.facelets.AbstractFaceletContext;
  import org.apache.myfaces.view.facelets.FaceletCompositionContext;
  import org.apache.myfaces.view.facelets.tag.MetaRulesetImpl;
  import org.apache.myfaces.view.facelets.tag.jsf.core.AjaxHandler;
  import org.apache.myfaces.view.facelets.tag.jsf.core.FacetHandler;
  
  /**
   *  
   * Implementation of the tag logic used in the JSF specification. 
   * 
   * @see org.apache.myfaces.view.facelets.tag.jsf.ComponentHandler
   * @author Leonardo Uribe (latest modification by $Author: lu4242 $)
   * @version $Revision: 1346023 $ $Date: 2012-06-04 11:10:17 -0500 (Mon, 04 Jun 2012) $
   *
   * @since 2.0
   */
  public class ComponentTagHandlerDelegate extends TagHandlerDelegate
  {
      private final static Logger log = Logger.getLogger(ComponentTagHandlerDelegate.class.getName());
  
      private final ComponentHandler _delegate;
  
      private final String _componentType;
  
      private final TagAttribute _id;
  
      private final String _rendererType;
      
      private final ComponentBuilderHandler _componentBuilderHandlerDelegate;
      
      private final RelocatableResourceHandler _relocatableResourceHandler;
  
      @SuppressWarnings("unchecked")
      public ComponentTagHandlerDelegate(ComponentHandler delegate)
      {
          _delegate = delegate;
          
          ComponentHandler handler = _delegate;
          boolean found = false;
          while(handler != null && !found)
          {
              if (handler instanceof ComponentBuilderHandler)
              {
                  found = true;
              }
              else if (handler instanceof FacesWrapper)
              {
                  handler = ((FacesWrapper<? extends ComponentHandler>)handler).getWrapped();
             }
             else
             {
                 handler = null;
             }
         }
         if (found)
         {
             _componentBuilderHandlerDelegate = (ComponentBuilderHandler) handler;
         }
         else
         {
             _componentBuilderHandlerDelegate = null;
         }
         
         //Check if this component is instance of RelocatableResourceHandler
         handler = _delegate;
         found = false;
         while(handler != null && !found)
         {
             if (handler instanceof RelocatableResourceHandler)
             {
                 found = true;
             }
             else if (handler instanceof FacesWrapper)
             {
                 handler = ((FacesWrapper<? extends ComponentHandler>)handler).getWrapped();
             }
             else
             {
                 handler = null;
             }
         }
         if (found)
         {
             _relocatableResourceHandler = (RelocatableResourceHandler) handler;
         }
         else
         {
             _relocatableResourceHandler = null;
         }
         
         ComponentConfig delegateComponentConfig = delegate.getComponentConfig();
         _componentType = delegateComponentConfig.getComponentType();
         _rendererType = delegateComponentConfig.getRendererType();
         _id = delegate.getTagAttribute("id");
     }
 
     /**
      * Method handles UIComponent tree creation in accordance with the JSF 1.2 spec.
      * <ol>
      * <li>First determines this UIComponent's id by calling {@link #getId(FaceletContext) getId(FaceletContext)}.</li>
      * <li>Search the parent for an existing UIComponent of the id we just grabbed</li>
      * <li>If found, {@link FaceletCompositionContext#markForDeletion(UIComponent) mark} its children for deletion.</li>
      * <li>If <i>not</i> found, call {@link #createComponent(FaceletContext) createComponent}.
      * <ol>
      * <li>Only here do we apply
      * {@link javax.faces.view.facelets.TagHandler#setAttributes(FaceletCompositionContext, Object) attributes}</li>
      * <li>Set the UIComponent's id</li>
      * <li>Set the RendererType of this instance</li>
      * </ol>
      * </li>
      * <li>Now apply the nextHandler, passing the UIComponent we've created/found.</li>
      * <li>Now add the UIComponent to the passed parent</li>
      * <li>Lastly, if the UIComponent already existed (found),
      * then {@link #finalizeForDeletion(FaceletCompositionContext, UIComponent) finalize}
      * for deletion.</li>
      * </ol>
      * 
      * @see javax.faces.view.facelets.FaceletHandler#apply(javax.faces.view.facelets.FaceletContext,
      * javax.faces.component.UIComponent)
      * 
      * @throws TagException
      *             if the UIComponent parent is null
      */
     @SuppressWarnings("unchecked")
     @Override
     public void apply(FaceletContext ctx, UIComponent parent) throws IOException
     {
         // make sure our parent is not null
         if (parent == null)
         {
             throw new TagException(_delegate.getTag(), "Parent UIComponent was null");
         }
         
         FacesContext facesContext = ctx.getFacesContext();
 
         // possible facet scoped
         String facetName = this.getFacetName(ctx, parent);
 
         // our id
         String id = ctx.generateUniqueId(_delegate.getTagId());
 
         // Cast to use UniqueIdVendor stuff
         FaceletCompositionContext mctx = (FaceletCompositionContext) FaceletCompositionContext.getCurrentInstance(ctx);
                 
         // grab our component
         UIComponent c = null;
         //boolean componentFoundInserted = false;
 
         //Used to preserve the original parent. Note when the view is being refreshed, the real parent could be
         //another component.
         UIComponent oldParent = parent;
         
         if (mctx.isRefreshingSection())
         {
             if (_relocatableResourceHandler != null)
             {
                 c = _relocatableResourceHandler.findChildByTagId(ctx, parent, id);
             }
             else
             {
                 c = ComponentSupport.findChildByTagId(parent, id); 
             }
         }
         boolean componentFound = false;
         if (c != null)
         {
             componentFound = true;
             
             mctx.incrementUniqueComponentId();
             
             // mark all children for cleaning
             if (log.isLoggable(Level.FINE))
             {
                 log.fine(_delegate.getTag() + " Component[" + id + "] Found, marking children for cleanup");
             }
             mctx.markForDeletion(c);
         }
         else
         {
             c = this.createComponent(ctx);
             if (log.isLoggable(Level.FINE))
             {
                 log.fine(_delegate.getTag() + " Component[" + id + "] Created: " + c.getClass().getName());
             }
             
             _delegate.setAttributes(ctx, c);
 
             // mark it owned by a facelet instance
             c.getAttributes().put(ComponentSupport.MARK_CREATED, id);
 
             if (facesContext.isProjectStage(ProjectStage.Development))
             {
                 c.getAttributes().put(UIComponent.VIEW_LOCATION_KEY,
                         _delegate.getTag().getLocation());
             }
 
             // assign our unique id
             if (this._id != null)
             {
                 mctx.incrementUniqueComponentId();
                 c.setId(this._id.getValue(ctx));
             }
             else
             {
                 String componentId = mctx.generateUniqueComponentId();
                 UniqueIdVendor uniqueIdVendor = mctx.getUniqueIdVendorFromStack();
                 if (uniqueIdVendor == null)
                 {
                     uniqueIdVendor = facesContext.getViewRoot();
                     
                     if (uniqueIdVendor == null)
                     {
                         // facesContext.getViewRoot() returns null here if we are in
                         // phase restore view, so we have to try to get the view root
                         // via the method in ComponentSupport and our parent
                         uniqueIdVendor = ComponentSupport.getViewRoot(ctx, parent);
                     }
                 }
                 if (uniqueIdVendor != null)
                 {
                     // UIViewRoot implements UniqueIdVendor, so there is no need to cast to UIViewRoot
                     // and call createUniqueId()
                     String uid = uniqueIdVendor.createUniqueId(facesContext, componentId);
                     c.setId(uid);
                 }
             }
 
             if (this._rendererType != null)
             {
                 c.setRendererType(this._rendererType);
             }
 
             // hook method
             _delegate.onComponentCreated(ctx, c, parent);
         }
         c.pushComponentToEL(facesContext, c);
 
         if (c instanceof UniqueIdVendor)
         {
             mctx.pushUniqueIdVendorToStack((UniqueIdVendor)c);
         }
         // first allow c to get populated
         _delegate.applyNextHandler(ctx, c);
 
         boolean oldProcessingEvents = facesContext.isProcessingEvents();
         // finish cleaning up orphaned children
         if (componentFound)
         {
             mctx.finalizeForDeletion(c);
 
             //if (!componentFoundInserted)
             //{
                 if (mctx.isRefreshingSection())
                 {
                     facesContext.setProcessingEvents(false);
                     if (_relocatableResourceHandler != null &&
                         parent != null && !parent.equals(c.getParent()))
                     {
                         // Replace parent with the relocated parent.
                         parent = c.getParent();
                     }
                 }
                 if (facetName == null)
                 {
                     parent.getChildren().remove(c);
                 }
                 else
                 {
                     ComponentSupport.removeFacet(ctx, parent, c, facetName);
                 }
                 if (mctx.isRefreshingSection())
                 {
                     facesContext.setProcessingEvents(oldProcessingEvents);
                 }
             //}
         }
 
 
         if (!componentFound)
         {
             if (c instanceof ClientBehaviorHolder && !UIComponent.isCompositeComponent(c))
             {
                 Iterator<AjaxHandler> it = ((AbstractFaceletContext) ctx).getAjaxHandlers();
                 if (it != null)
                 {
                     while(it.hasNext())
                     {
                         it.next().applyAttachedObject(facesContext, c);
                     }
                 }
             }
             
             if (c instanceof EditableValueHolder)
             {
                 // add default validators here, because this feature 
                 // is only available in facelets (see MYFACES-2362 for details)
                 addEnclosingAndDefaultValidators(ctx, mctx, facesContext, (EditableValueHolder) c);
             }
         }
         
         _delegate.onComponentPopulated(ctx, c, oldParent);
 
         if (componentFound && mctx.isRefreshingSection())
         {
             facesContext.setProcessingEvents(false);
         }
         if (facetName == null)
         {
             parent.getChildren().add(c);
         }
         else
         {
             ComponentSupport.addFacet(ctx, parent, c, facetName);
         }
         if (componentFound && mctx.isRefreshingSection())
         {
             facesContext.setProcessingEvents(oldProcessingEvents);
         }
 
         if (c instanceof UniqueIdVendor)
         {
             mctx.popUniqueIdVendorToStack();
         }
 
         c.popComponentFromEL(facesContext);
         
         if (mctx.isMarkInitialState())
         {
             //Call it only if we are using partial state saving
             c.markInitialState();
         }
     }
     
     /**
      * Return the Facet name we are scoped in, otherwise null
      * 
      * @param ctx
      * @return
      */
     protected final String getFacetName(FaceletContext ctx, UIComponent parent)
     {
         return (String) parent.getAttributes().get(FacetHandler.KEY);
     }
 
     /**
      * If the binding attribute was specified, use that in conjuction with our componentType String variable to call
      * createComponent on the Application, otherwise just pass the componentType String. <p /> If the binding was used,
      * then set the ValueExpression "binding" on the created UIComponent.
      * 
      * @see Application#createComponent(javax.faces.el.ValueBinding, javax.faces.context.FacesContext, java.lang.String)
      * @see Application#createComponent(java.lang.String)
      * @param ctx
      *            FaceletContext to use in creating a component
      * @return
      */
     protected UIComponent createComponent(FaceletContext ctx)
     {
         if (_componentBuilderHandlerDelegate != null)
         {
             // the call to Application.createComponent(FacesContext, Resource)
             // is delegated because we don't have here the required Resource instance
             return _componentBuilderHandlerDelegate.createComponent(ctx);
         }
         UIComponent c = null;
         FacesContext faces = ctx.getFacesContext();
         Application app = faces.getApplication();
         if (_delegate.getBinding() != null)
         {
             ValueExpression ve = _delegate.getBinding().getValueExpression(ctx, Object.class);
             if (this._rendererType == null)
             {
                 c = app.createComponent(ve, faces, this._componentType);
             }
             else
             {
                 c = app.createComponent(ve, faces, this._componentType, this._rendererType);
             }
             if (c != null)
             {
                 c.setValueExpression("binding", ve);
                 
                 if (!ve.isReadOnly(faces.getELContext()))
                 {
                     ComponentSupport.getViewRoot(ctx, c).getAttributes().put("oam.CALL_PRE_DISPOSE_VIEW", Boolean.TRUE);
                     c.subscribeToEvent(PreDisposeViewEvent.class, new ClearBindingValueExpressionListener());
                 }
             }
         }
         else
         {
             // According to the, spec call the second alternative with null rendererType gives
             // the same result, but without the unnecesary call for FacesContext.getCurrentInstance().
             // Saves 1 call per component without rendererType (f:viewParam, h:column, f:selectItem, ...)
             // and it does not have any side effects (the spec javadoc mentions in a explicit way
             // that rendererType can be null!).
             /*
             if (this._rendererType == null)
             {
                 c = app.createComponent(this._componentType);
             }
             else
             {*/
                 c = app.createComponent(faces, this._componentType, this._rendererType);
             //}
         }
         return c;
     }
 
     /**
      * If the id TagAttribute was specified, get it's value, otherwise generate a unique id from our tagId.
      * 
      * @see TagAttribute#getValue(FaceletContext)
      * @param ctx
      *            FaceletContext to use
      * @return what should be a unique Id
      */
     protected String getId(FaceletContext ctx)
     {
         if (this._id != null)
         {
             return this._id.getValue(ctx);
         }
         return ctx.generateUniqueId(_delegate.getTagId());
     }
 
     @Override
     public MetaRuleset createMetaRuleset(Class type)
     {
         MetaRuleset m = new MetaRulesetImpl(_delegate.getTag(), type);
         // ignore standard component attributes
         m.ignore("binding").ignore("id");
 
         // add auto wiring for attributes
         m.addRule(ComponentRule.INSTANCE);
 
         // if it's an ActionSource
         if (ActionSource.class.isAssignableFrom(type))
         {
             m.addRule(ActionSourceRule.INSTANCE);
         }
 
         // if it's a ValueHolder
         if (ValueHolder.class.isAssignableFrom(type))
         {
             m.addRule(ValueHolderRule.INSTANCE);
 
             // if it's an EditableValueHolder
             if (EditableValueHolder.class.isAssignableFrom(type))
             {
                 m.ignore("submittedValue");
                 m.ignore("valid");
                 m.addRule(EditableValueHolderRule.INSTANCE);
             }
         }
         
         return m;
     }
     
     /**
      * Add the default Validators to the component.
      * Also adds all validators specified by enclosing <f:validateBean> tags
      * (e.g. the BeanValidator if it is not a default validator).
      *
      * @param context The FacesContext.
      * @param mctx the AbstractFaceletContext
      * @param component The EditableValueHolder to which the validators should be added
      */
     private void addEnclosingAndDefaultValidators(FaceletContext ctx, 
                                       FaceletCompositionContext mctx, 
                                       FacesContext context, 
                                       EditableValueHolder component)
     {
         // add all enclosing validators, because they have precedence over default validators.
         Iterator<Map.Entry<String, EditableValueHolderAttachedObjectHandler>> enclosingValidatorIds =
             mctx.getEnclosingValidatorIdsAndHandlers();
         if (enclosingValidatorIds != null)
         {
             while (enclosingValidatorIds.hasNext())
             {
                 Map.Entry<String, EditableValueHolderAttachedObjectHandler> entry = enclosingValidatorIds.next();
                 addEnclosingValidator(ctx, mctx, context, component, entry.getKey(), entry.getValue());
             }
         }
         // add all defaultValidators
         Map<String, String> defaultValidators = context.getApplication().getDefaultValidatorInfo();
         if (defaultValidators != null && defaultValidators.size() != 0)
         {
             for (Map.Entry<String, String> entry : defaultValidators.entrySet())
             {
                 if (!mctx.containsEnclosingValidatorId(entry.getKey()))
                 {
                     addDefaultValidator(ctx, mctx, context, component, entry.getKey(), entry.getValue());
                 }
             }
         }
     }
 
     private void addDefaultValidator(FaceletContext ctx, FaceletCompositionContext mctx, FacesContext context, 
             EditableValueHolder component, String validatorId, String validatorClassName)
     {
         Validator enclosingValidator = null;
         
         if (validatorClassName == null)
         {
             // we have no class name for validators of enclosing <f:validateBean> tags
             // --> we have to create it to get the class name
             // note that normally we can use this instance later anyway!
             enclosingValidator = context.getApplication().createValidator(validatorId);
             validatorClassName = enclosingValidator.getClass().getName();
         }
         
         // check if the validator is already registered for the given component
         // this happens if <f:validateBean /> is nested inside the component on the view
         Validator validator = null;
         for (Validator v : component.getValidators())
         {
             if (v.getClass().getName().equals(validatorClassName))
             {
                 // found
                 validator = v;
                 break;
             }
         }
         
         if (validator == null)
         {
             if (shouldAddDefaultValidator(ctx, mctx, context, component, validatorId))
             {
                 if (enclosingValidator != null)
                 {
                     // we can use the instance from before
                     validator = enclosingValidator;
                 }
                 else
                 {
                     // create it
                     validator = context.getApplication().createValidator(validatorId);
                 }
                 // add the validator to the component
                 component.addValidator(validator);
             }
             else
             {
                 // we should not add the validator
                 return;
             }
         }
         
         // special things to configure for a BeanValidator
         if (validator instanceof BeanValidator)
         {
             BeanValidator beanValidator = (BeanValidator) validator;
             
             // check the validationGroups
             String validationGroups =  beanValidator.getValidationGroups();
             if (validationGroups == null 
                     || validationGroups.matches(BeanValidator.EMPTY_VALIDATION_GROUPS_PATTERN))
             {
                 // no validationGroups available
                 // --> get the validationGroups from the stack
                 //String stackGroup = mctx.getFirstValidationGroupFromStack();
                 //if (stackGroup != null)
                 //{
                 //    validationGroups = stackGroup;
                 //}
                 //else
                 //{
                     // no validationGroups on the stack
                     // --> set the default validationGroup
                     validationGroups = javax.validation.groups.Default.class.getName();
                 //}
                 beanValidator.setValidationGroups(validationGroups);
             }
         }
     }
 
     /**
      * Determine if the validator with the given validatorId should be added.
      *
      * @param validatorId The validatorId.
      * @param facesContext The FacesContext.
      * @param mctx the AbstractFaceletContext
      * @param component The EditableValueHolder to which the validator should be added.
      * @return true if the Validator should be added, false otherwise.
      */
     @SuppressWarnings("unchecked")
     private boolean shouldAddDefaultValidator(FaceletContext ctx, FaceletCompositionContext mctx,
                                               FacesContext facesContext,
                                               EditableValueHolder component, 
                                               String validatorId)
     {
         // check if the validatorId is on the exclusion list on the component
         List<String> exclusionList 
                 = (List<String>) ((UIComponent) component).getAttributes()
                         .get(ValidatorTagHandlerDelegate.VALIDATOR_ID_EXCLUSION_LIST_KEY);
         if (exclusionList != null)
         {
             for (String excludedId : exclusionList)
             {
                 if (excludedId.equals(validatorId))
                 {
                     return false;
                 }
             }
         }
         
         // check if the validatorId is on the exclusion list on the stack
         /*
         Iterator<String> it = mctx.getExcludedValidatorIds();
         if (it != null)
         {            
             while (it.hasNext())
             {
                 String excludedId = it.next();
                 if (excludedId.equals(validatorId))
                 {
                     return false;
                 }
             }
         }*/
         Iterator<Map.Entry<String, EditableValueHolderAttachedObjectHandler>> enclosingValidatorIds =
             mctx.getEnclosingValidatorIdsAndHandlers();
         if (enclosingValidatorIds != null)
         {
             while (enclosingValidatorIds.hasNext())
             {
                 Map.Entry<String, EditableValueHolderAttachedObjectHandler> entry = enclosingValidatorIds.next();
                 boolean validatorIdAvailable = entry.getKey() != null && !"".equals(entry.getKey());
                 if (validatorIdAvailable && entry.getKey().equals(validatorId))
                 {
                     if (((ValidatorHandler)((FacesWrapper<ValidatorHandler>)entry.getValue()).getWrapped())
                             .isDisabled(ctx))
                     {
                         return false;
                     }
                 }
             }
         }
         
         // Some extra rules are required for Bean Validation.
         if (validatorId.equals(BeanValidator.VALIDATOR_ID))
         {
             if (!ExternalSpecifications.isBeanValidationAvailable())
             {
                 // the BeanValidator was added as a default-validator, but
                 // bean validation is not available on the classpath.
                 // --> log a warning about this scenario.
                 log.log(Level.WARNING, "Bean validation is not available on the " +
                         "classpath, thus the BeanValidator will not be added for " +
                         "the component " + component);
                 return false;
             }
         }
 
         // By default, all default validators should be added
         return true;
     }
 
     private void addEnclosingValidator(FaceletContext ctx, FaceletCompositionContext mctx, FacesContext context, 
             EditableValueHolder component, String validatorId, 
             EditableValueHolderAttachedObjectHandler attachedObjectHandler)
     {
         if (shouldAddEnclosingValidator(mctx, context, component, validatorId))
         {
             if (attachedObjectHandler != null)
             {
                 attachedObjectHandler.applyAttachedObject(context, (UIComponent) component);
             }
             else
             {
                 Validator validator = null;
                 // create it
                 validator = context.getApplication().createValidator(validatorId);
 
                 // special things to configure for a BeanValidator
                 if (validator instanceof BeanValidator)
                 {
                     BeanValidator beanValidator = (BeanValidator) validator;
                     
                     // check the validationGroups
                     String validationGroups =  beanValidator.getValidationGroups();
                     if (validationGroups == null 
                             || validationGroups.matches(BeanValidator.EMPTY_VALIDATION_GROUPS_PATTERN))
                     {
                         // no validationGroups available
                         // --> get the validationGroups from the stack
                         //String stackGroup = mctx.getFirstValidationGroupFromStack();
                         //if (stackGroup != null)
                         //{
                         //    validationGroups = stackGroup;
                         //}
                         //else
                         //{
                             // no validationGroups on the stack
                             // --> set the default validationGroup
                             validationGroups = javax.validation.groups.Default.class.getName();
                         //}
                         beanValidator.setValidationGroups(validationGroups);
                     }
                 }
                 
                 // add the validator to the component
                 component.addValidator(validator);
             }
         }
     }
 
     /**
      * Determine if the validator with the given validatorId should be added.
      * 
      * The difference here with shouldAddEnclosingValidator is the inner one has
      * precedence over the outer one, so a disable="true" over the same outer 
      * validator, the inner one should ignore this condition. 
      * 
      * @param mctx
      * @param facesContext
      * @param component
      * @param validatorId
      * @return
      */
     @SuppressWarnings("unchecked")
     private boolean shouldAddEnclosingValidator(FaceletCompositionContext mctx,
             FacesContext facesContext,
             EditableValueHolder component, 
             String validatorId)
     {
         // check if the validatorId is on the exclusion list on the component
         List<String> exclusionList = (List<String>) ((UIComponent) component)
                 .getAttributes()
                 .get(ValidatorTagHandlerDelegate.VALIDATOR_ID_EXCLUSION_LIST_KEY);
         if (exclusionList != null)
         {
             for (String excludedId : exclusionList)
             {
                 if (excludedId.equals(validatorId))
                 {
                     return false;
                 }
             }
         }
 
         // Some extra rules are required for Bean Validation.
         if (validatorId.equals(BeanValidator.VALIDATOR_ID))
         {
             if (!ExternalSpecifications.isBeanValidationAvailable())
             {
                 // the BeanValidator was added as a default-validator, but
                 // bean validation is not available on the classpath.
                 // --> log a warning about this scenario.
                 log.log(Level.WARNING,
                         "Bean validation is not available on the "
                                 + "classpath, thus the BeanValidator will not be added for "
                                 + "the component " + component);
                 return false;
             }
         }
 
         // By default, all default validators should be added
         return true;
     }
 }