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    
015    package org.apache.tapestry5.corelib.mixins;
016    
017    import org.apache.tapestry5.BindingConstants;
018    import org.apache.tapestry5.ComponentResources;
019    import org.apache.tapestry5.EventConstants;
020    import org.apache.tapestry5.EventContext;
021    import org.apache.tapestry5.Link;
022    import org.apache.tapestry5.annotations.AfterRender;
023    import org.apache.tapestry5.annotations.Import;
024    import org.apache.tapestry5.annotations.InjectContainer;
025    import org.apache.tapestry5.annotations.Parameter;
026    import org.apache.tapestry5.corelib.components.Zone;
027    import org.apache.tapestry5.internal.util.CaptureResultCallback;
028    import org.apache.tapestry5.ioc.annotations.Inject;
029    import org.apache.tapestry5.json.JSONObject;
030    import org.apache.tapestry5.services.javascript.InitializationPriority;
031    import 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")
043    public 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    }