001// Copyright 2011 The Apache Software Foundation
002//
003// Licensed under the Apache License, Version 2.0 (the "License");
004// you may not use this file except in compliance with the License.
005// You may obtain a copy of the License at
006//
007//     http://www.apache.org/licenses/LICENSE-2.0
008//
009// Unless required by applicable law or agreed to in writing, software
010// distributed under the License is distributed on an "AS IS" BASIS,
011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012// See the License for the specific language governing permissions and
013// limitations under the License.
014
015package org.apache.tapestry5.corelib.mixins;
016
017import org.apache.tapestry5.BindingConstants;
018import org.apache.tapestry5.ComponentResources;
019import org.apache.tapestry5.EventConstants;
020import org.apache.tapestry5.EventContext;
021import org.apache.tapestry5.Link;
022import org.apache.tapestry5.annotations.AfterRender;
023import org.apache.tapestry5.annotations.Import;
024import org.apache.tapestry5.annotations.InjectContainer;
025import org.apache.tapestry5.annotations.Parameter;
026import org.apache.tapestry5.corelib.components.Zone;
027import org.apache.tapestry5.internal.util.CaptureResultCallback;
028import org.apache.tapestry5.ioc.annotations.Inject;
029import org.apache.tapestry5.json.JSONObject;
030import org.apache.tapestry5.services.javascript.InitializationPriority;
031import org.apache.tapestry5.services.javascript.JavaScriptSupport;
032
033/**
034 * <p>
035 * This mixin periodically refreshs a @{link org.apache.tapestry5.corelib.components.Zone zone}
036 * by triggering an event on the server using ajax requests. 
037 * </p>
038 * 
039 * <b>Note: </b> This mixin is only meant for a @{link org.apache.tapestry5.corelib.components.Zone zone}
040 * @tapestrydoc
041 */
042@Import(library = "zone-refresh.js")
043public class ZoneRefresh
044{
045   /**
046    *  Period between two consecutive refreshes (in seconds)  
047    */
048   @Parameter(required = true, defaultPrefix = BindingConstants.LITERAL)
049   private int period;
050   
051   /**
052    * Context passed to the event
053    */
054   @Parameter
055   private Object[] context;
056   
057   @InjectContainer
058   private Zone zone;
059
060   @Inject
061   private JavaScriptSupport javaScriptSupport;
062   
063   @Inject
064   private ComponentResources resources;
065   
066   public ZoneRefresh()
067   {
068   }
069   
070   //For testing purpose
071   ZoneRefresh(Object [] context, ComponentResources resources, JavaScriptSupport javaScriptSupport, Zone zone)
072   {
073      this.context = context;
074      this.resources = resources;
075      this.javaScriptSupport = javaScriptSupport;
076      this.zone = zone;
077   }
078
079   @AfterRender
080   void addJavaScript()
081   {
082      JSONObject params = new JSONObject();
083      
084      params.put("period", period);
085      params.put("id", zone.getClientId());
086      params.put("URL", createEventLink());
087      
088      javaScriptSupport.addInitializerCall(InitializationPriority.LATE, "zoneRefresh", params);
089   }
090
091   private Object createEventLink()
092   {
093      Link link = resources.createEventLink("zoneRefresh", context);
094      return link.toAbsoluteURI();
095   }
096   
097   Object onZoneRefresh(EventContext eventContext)
098   {
099      CaptureResultCallback<Object> callback = new CaptureResultCallback<Object>();
100      resources.triggerContextEvent(EventConstants.REFRESH, eventContext, callback);
101      
102      if(callback.getResult() != null){
103         return callback.getResult();
104      }
105      
106      return zone.getBody();
107   }
108
109}