Example usage of PageCallback:

The Home page ensure a user is authenticated in the validate(IRequestCycle) method. If the user is not authenticated, they are redirected to the Login page, after setting a callback in the Login page.

The Login page formSubmit() IActionListener authenticates the user and then invokes performCallback(IRequestCycle) to the Home page.

  public class Home extends BasePage {
 
      public void validate(IRequestCycle cycle) {            
          Visit visit = (Visit) getVisit();
      
          if (!visit.isAuthenticated()) {
              Login login = (Login) cycle.getPage("Login");

              login.setCallback(new PageCallback(this));
              
              throw new PageRedirectException(login);
          }            
      }
  }

  public Login extends BasePage {
 
      private ICallback _callback;

      public void setCallback(ICallback _callback) {
          _callback = callback;
      }

      public void formSubmit(IRequestCycle cycle) {
          // Authentication code
          ..
   
          Visit visit = (Visit) getVisit();

          visit.setAuthenticated(true);
  
          if (_callback != null) {
              _callback.performCallback(cycle);
          }
      }
  }