/*

  * 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 javax.el.ValueExpression;

 import javax.faces.component.UIComponent;

 import javax.faces.component.behavior.Behavior;

 import javax.faces.component.behavior.ClientBehavior;

 import javax.faces.component.behavior.ClientBehaviorHolder;

 import javax.faces.context.FacesContext;

 import javax.faces.view.BehaviorHolderAttachedObjectHandler;

 import javax.faces.view.facelets.BehaviorHandler;

 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.TagAttributeException;

 import javax.faces.view.facelets.TagException;

 import javax.faces.view.facelets.TagHandlerDelegate;

 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;

 /**

  * @author Leonardo Uribe (latest modification by $Author$)

  * @version $Revision$ $Date$

  *

  * @since 2.0

  */

 public class BehaviorTagHandlerDelegate extends TagHandlerDelegate implements BehaviorHolderAttachedObjectHandler

 {

     private BehaviorHandler _delegate;

     public BehaviorTagHandlerDelegate(BehaviorHandler delegate)

     {

         _delegate = delegate;

     }

     @Override

     public void apply(FaceletContext ctx, UIComponent parent) throws IOException

     {

         if (!ComponentHandler.isNew(parent))

         {

             return;

         }

         // Note that the only contract defined at this moment based on behavior api

         // is client behavior, so it is enough to cast it here. In the future, new

         // implementations should be added here.

         if (parent instanceof ClientBehaviorHolder)

         {

             applyAttachedObject(ctx.getFacesContext(), parent);

         }

         else if (UIComponent.isCompositeComponent(parent))

         {

             FaceletCompositionContext mctx = FaceletCompositionContext.getCurrentInstance(ctx);

             // It is supposed that for composite components, this tag should

             // add itself as a target, but note that on whole api does not exists

             // some tag that expose client behaviors as targets for composite

             // components. In RI, there exists a tag called composite:clientBehavior,

             // but does not appear on spec or javadoc, maybe because this could be

             // understand as an implementation detail, after all there exists a key

             // called AttachedObjectTarget.ATTACHED_OBJECT_TARGETS_KEY that could be

             // used to create a tag outside jsf implementation to attach targets.

             mctx.addAttachedObjectHandler(parent, _delegate);

         }

         else

         {

             throw new TagException(_delegate.getTag(),

                     "Parent not composite component or an instance of ClientBehaviorHolder: " + parent);

         }

     }

     protected Behavior createBehavior(FaceletContext ctx)

     {

         if (_delegate.getBehaviorId() == null)

         {

             throw new TagException(

                                    _delegate.getTag(),

                                    "No behavior id defined");

         }

         return ctx.getFacesContext().getApplication().createBehavior(_delegate.getBehaviorId());

     }

     /**

      * This tag call _delegate.setAttributes, so the returned MetaRuleset

      * should ignore attributes that are not supposed to be there like

      * "binding" and "event"

      */

     @Override

     public MetaRuleset createMetaRuleset(Class type)

     {

         MetaRuleset ruleset = new MetaRulesetImpl(_delegate.getTag(), type);

         ruleset.ignore("binding");

         ruleset.ignore("event");

         return ruleset;

     }

     /**

      * Create a ClientBehavior and attach it to the component

      */

     public void applyAttachedObject(FacesContext context, UIComponent parent)

     {

         // Retrieve the current FaceletContext from FacesContext object

         FaceletContext faceletContext = (FaceletContext) context.getAttributes().get(

                 FaceletContext.FACELET_CONTEXT_KEY);

         ValueExpression ve = null;

         Behavior behavior = null;

         if (_delegate.getBinding() != null)

         {

             ve = _delegate.getBinding().getValueExpression(faceletContext, Behavior.class);

             behavior = (Behavior) ve.getValue(faceletContext);

         }

         if (behavior == null)

         {

             behavior = this.createBehavior(faceletContext);

             if (ve != null)

             {

                 ve.setValue(faceletContext, behavior);

             }

         }

         if (behavior == null)

         {

             throw new TagException(_delegate.getTag(), "No Validator was created");

         }

         _delegate.setAttributes(faceletContext, behavior);

         if (behavior instanceof ClientBehavior)

         {

             // cast to a ClientBehaviorHolder

             ClientBehaviorHolder cvh = (ClientBehaviorHolder) parent;

             // TODO: check if the behavior could be applied to the current parent

             // For run tests it is not necessary, so we let this one pending.

             // It is necessary to obtain a event name for add it, so we have to

             // look first to the defined event name, otherwise take the default from

             // the holder

             String eventName = getEventName();

             if (eventName == null)

             {

                 eventName = cvh.getDefaultEventName();

             }

             if (eventName == null)

             {

                 throw new TagAttributeException(_delegate.getEvent(),

                         "eventName could not be defined for client behavior "+ behavior.toString());

             }

             else if (!cvh.getEventNames().contains(eventName))

             {

                 throw new TagAttributeException(_delegate.getEvent(),

                         "eventName "+eventName+" not found on component instance");

             }

             else

             {

                 cvh.addClientBehavior(eventName, (ClientBehavior) behavior);

             }

             AjaxHandler.registerJsfAjaxDefaultResource(faceletContext, parent);

         }

     }

     public String getFor()

     {

         TagAttribute forAttribute = _delegate.getTagAttribute("for");

         if (forAttribute == null)

         {

             return null;

         }

         else

         {

             return forAttribute.getValue();

         }

     }

     public String getEventName()

     {

         return _delegate.getEventName();

     }

 }