Start Execution in Foreign Ajax Channel

Employment/Purpose

Here we describe how to start a ZK execution in a foreign Ajax channel. For example, JSF 2 allows developers to send back JavaScript code to update the browser in JSF's Ajax channel.

Bridge

Starting an execution in a foreign Ajax channel is straightforward: invoke Bridge.start(ServletContext, HttpServletRequest, HttpServletResponse, Desktop). Then, you are allowed to access the components, post events and do anything you like. At the end, you invoke Bridge.getResult() to retrieve the JavaScript code snippet and send it back to the client to execute. Finally, you invoke Bridge.close() to close the execution.

<syntax lang="java"> Bridge bridge = Bridge.start(svlctx, request, response, desktop); try {

   //execution started, do whatever you want

   String jscode = bridge.getResult();

   //send jscode back with the foreign Ajax channel.

} finally {

   bridge.close(); //end of execution and cleanup

} </syntax>

Example

Start Execution in JSF 2 ActionListener

In JSF 2.0 developers can initiate Ajax request using jsf.ajax.request For e.g. <syntax lang="xml"> ...

  <h:commandButton id="save" value="Save"
   onclick="jsf.ajax.request(this, event, {execute:'@all'}); return false;" actionListener="${myBean.saveDetails}">
  </h:commandButton>

... </syntax>

and in your ActionListener

<syntax lang="java" high="12,22,28"> @ManagedBean @SessionScoped public class MyBean {

  public void saveDetails(ActionEvent e)  throws IOException {

     ExternalContext ec = FacesContext.getCurrentInstance().getExternalContext();
     ServletContext svlctx = (ServletContext) ec.getContext();
     HttpServletRequest request = (HttpServletRequest) ec.getRequest();
     HttpServletResponse response = (HttpServletResponse) ec.getResponse();
     Component comp = getComponent();
     Bridge bridge = Bridge.start(svlctx, request, response,comp.getDesktop());
     try {
             // update ZK component(s) state here
             //comp.appendChild(new SomethingElse()); ...

             //Send back bridge.getResult() with the response writer (eval)
             PartialResponseWriter responseWriter =
               FacesContext.getCurrentInstance().getPartialViewContext().getPartialResponseWriter();
             responseWriter.startDocument();
             responseWriter.startEval();
             responseWriter.write(bridge.getResult());
             responseWriter.endEval();
             responseWriter.endDocument();
             responseWriter.flush();
             responseWriter.close();
     } finally {
             bridge.close();
     }
 }

 private Component getComponent() {
     //locate the component that you want to handle
 }

} </syntax>

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Version History

Version	Date	Content
5.0.5	September 2010	Bridge was introduced to simplify the starting of an execution in foreign Ajax channel