java - Vaadin 7.1.0 推送

Question

我是 Vaadin 的新手，只是实现了一个原型(prototype)来测试功能。目前我正在尝试 Vaadin 服务器推送功能。 我喜欢做一个简单的计数器，可以通过按钮增加。之后，我喜欢从不同的浏览器打开这一面，当我计数时，我喜欢更新所有浏览器。

现在我已经知道当前浏览器是由一个单独的线程更新的。

public class PushTestView extends VerticalLayout implements View {

   private static final long serialVersionUID = -8056849522760207972L;
   private Label counter;

   public void enter(ViewChangeEvent event) {
      removeAllComponents();
      PushTestController controller = PushTestController.getInstance();
      counter = new Label("" + controller.getCounter());
      Button button = new Button("Count up");

      button.addClickListener(new ClickListener() {
         private static final long serialVersionUID = -1437136914245802675L;

         @Override
         public void buttonClick(ClickEvent event) {
            InitializerThread thread = new InitializerThread();
            thread.run();
         }
      });

      addComponent(counter);
      addComponent(button);

   }

   class InitializerThread extends Thread {
      @Override
      public void run() {
         // Init done, update the UI after doing locking
         UI.getCurrent().access(new Runnable() {
            @Override
            public void run() {
               // Here the UI is locked and can be updated
               PushTestController.getInstance().countUp();
               counter.setValue("" + PushTestController.getInstance().getCounter());
               UI.getCurrent().notifyAll();
            }
         });
      }
   }
}

我将此 View 嵌入到我的 UI 中，并用 @Push 进行注释。 这是我的 Controller :

public class PushTestController {

   private static PushTestController instance = new PushTestController();
   private int counter = 0;

   private PushTestController() {
      //Private Constructor for Singleton 
   }

   public static PushTestController getInstance() {
      return instance;
   }

   public int getCounter() {
      return counter;
   }

   public String getCounterString() {
      return "" + counter;
   }

   public void countUp() {
      counter++;
   }
}

我如何扩展此示例以使其能够在不同浏览器中更新 UI？

Answer 1

看看这个，第 11.16.3 节:https://vaadin.com/book/vaadin7/-/page/advanced.push.html