Remote procedure calls

Are you wondering how a widget can send a message to the related server component? If you have been curious, you might have noticed an addClickHandler method that you can use in your widget. That method seems to be appropriate. The problem is that by using this method you have to implement the click logic in the widget, which means that the click event will be handled in the client.

Remote Procedure Calls (RPC) will solve the problem. RPC are made through an interface that extends Vaadin's ServerRpc. For example:

public interface MarqueeLabelServerRpc extends ServerRpc {

  public void clicked();

}

Note

ServerRpc is used for communication from client to server. You have to extend ClientRpc if your communication is going from server to client though.

The previous interface declares a method that can be called from the client side. Normally, the call will be done from the connector (it makes sense to implement a connection feature in the connector, right?). To make the call...