如何在事件接收后重新渲染 Wicket 组件

Question

我有一个 Wicket 组件正在侦听某个事件 (IEvent)。如果发生此类事件，我想使用更改后的模型重新渲染组件。页面上没有活动控件，例如AjaxLink，可以触发重新渲染。

有没有办法刷新这种组件？

我想以某种方式触发来自 onEvent 方法的 AJAX 请求，并向提到的组件添加一个 AjaxBehavior。但我不知道，如何触发 AJAX 请求。

public class PersonPanel extends Panel implements Observer {

    private WebMarkupContainer wrapper;

    public PersonPanel(String id) {
        super(id);

        setDefaultModel(new CompoundPropertyModel<PersonInfo>(getModel()));

        wrapper = new WebMarkupContainer("wrapper");
        wrapper.setOutputMarkupId(true);
        add(wrapper);

        wrapper.add(new Label("personID"));
        // some more content
    }

    private IModel<PersonInfo> getModel() {
        return new LoadableDetachableModel<PersonInfo>() {
            @Override
            protected PersonInfo load() {
                // model loading logic
            }
        };
    }

    @Override
    public void onEvent(IEvent<?> event) {
        logger.debug("\n   Person Panel received an Event: " + event.getPayload());

        // Re-rendering of "wrapper" should be triggered from here.
    }

    @Override
    public void update(Observable observable, Object o) {
        send(this, Broadcast.EXACT, "Observable cache has changed.");
    }
}

Answer 1

在send这边你可以通过AjaxRequestTarget和事件的payload。

send(getPage(), Broadcast.DEPTH, new MyPayload(target));

然后在接收端：

MyPayload payload = (MyPayload) event.getPayload();
payload.getTarget().add(this);

Answer 2

这是解决方案，感谢 martin-g 的提示，通过 WebSockets 解决。查看方法update和onEvent，加上组件上的WebSocketBehavior：

public class PersonPanel extends Panel implements Observer {

    private WebMarkupContainer wrapper;

    public PersonPanel(String id) {
        super(id);

        setDefaultModel(new CompoundPropertyModel<PersonInfo>(getModel()));

        wrapper = new WebMarkupContainer("wrapper");
        wrapper.setOutputMarkupId(true);
        add(wrapper);

        wrapper.add(new Label("personID"));
        // some more content

        add(new WebSocketBehavior() {
        });

        observableCache.addObserver(this);
    }

    private IModel<PersonInfo> getModel() {
        return new LoadableDetachableModel<PersonInfo>() {
            @Override
            protected PersonInfo load() {
                // model loading logic
            }
        };
    }

    @Override
    public void onEvent(IEvent<?> event) {
        if (event.getPayload() instanceof WebSocketPushPayload) {
            WebSocketPushPayload wsEvent = (WebSocketPushPayload) event.getPayload();
            wsEvent.getHandler().add(wrapper);
        }
    }

    @Override
    public void update(Observable observable, Object o) {
        WebSocketSettings webSocketSettings =
            WebSocketSettings.Holder.get(getApplication());
        WebSocketPushBroadcaster broadcaster =
            new WebSocketPushBroadcaster(webSocketSettings.getConnectionRegistry());
        broadcaster.broadcastAll(
                getApplication(),
                new WebSocketMessage("WebSocket message from the PersonPanel."));
    }

}

您可以在 Bitbucket 上的 Wicket 8 和 Gradle 中找到完整的运行示例项目:

sw-samuraj/blog-wicket-spring-rest

如何在事件接收后重新渲染 Wicket 组件

How to re-render Wicket component after the Event reception

ajax

wicket

websocket

java-websocket