// Copyright 2008 The Apache Software Foundation

 //

 // Licensed 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.tapestry5.corelib.mixins;

 import org.apache.tapestry5.BindingConstants;

 import org.apache.tapestry5.ClientElement;

 import org.apache.tapestry5.Field;

 import org.apache.tapestry5.RenderSupport;

 import org.apache.tapestry5.annotations.Environmental;

 import org.apache.tapestry5.annotations.InjectContainer;

 import org.apache.tapestry5.annotations.Parameter;

 import org.apache.tapestry5.json.JSONArray;

 import org.apache.tapestry5.services.Heartbeat;

 /**

  * A mixin that can be applied to a {@link org.apache.tapestry5.corelib.components.Checkbox} or {@link

  * org.apache.tapestry5.corelib.components.Radio} component that will link the input field and a {@link

  * org.apache.tapestry5.corelib.components.FormFragment}, making the field control the client-side visibility of the

  * FormFragment.

  */

 public class TriggerFragment

 {

     @InjectContainer

     private Field container;

     /**

      * The {@link org.apache.tapestry5.corelib.components.FormFragment} instance to make dynamically visible or hidden.

      */

     @Parameter(required = true, defaultPrefix = BindingConstants.COMPONENT, allowNull = false)

     private ClientElement fragment;

     @Environmental

     private RenderSupport renderSupport;

     @Environmental

     private Heartbeat heartbeat;

     void beginRender()

     {

         Runnable r = new Runnable()

         {

             public void run()

             {

                 JSONArray spec = new JSONArray();

                 spec.put(container.getClientId());

                 spec.put(fragment.getClientId());

                 renderSupport.addInit("linkTriggerToFormFragment", spec);

             }

         };

         // Defer generating the script to ensure that the FormFragment has rendered

         // and generated its client id.

         heartbeat.defer(r);

     }

 }