Wicket FutureUpdateBehavior: allows asynchronous update of components.

FutureUpdateBehavior.java

import org.apache.wicket.ajax.AbstractAjaxTimerBehavior;
import org.apache.wicket.ajax.AjaxRequestTarget;
import org.apache.wicket.util.time.Duration;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;

/**
 * An Ajax timer behavior that polls a future waiting for it to be done and
 * once it is updates the component model, stops the timer and calls a callback function.
 *
 * @author Jonny Wray
 */
public abstract class FutureUpdateBehavior<T> extends AbstractAjaxTimerBehavior{
    private final Logger logger = LoggerFactory.getLogger(FutureUpdateBehavior.class);
    private transient Future<T> future;

    public FutureUpdateBehavior(Duration updateInterval, Future<T> future) {
        super(updateInterval);
        this.future = future;
    }

    protected abstract void onPostSuccess(AjaxRequestTarget target);

    protected abstract void onUpdateError(AjaxRequestTarget target, Exception e);

    protected void onTimer(final AjaxRequestTarget target){
        if(future.isDone()){
            try{
                T data = future.get();
                getComponent().setDefaultModelObject(data);
                stop(target);
                onPostSuccess(target);
            }
            catch(InterruptedException e){
                stop(target);
                String message = "Error occurred while fetching data: "+e.getMessage();
                logger.error(message, e);
                onUpdateError(target, e);
            }
            catch(ExecutionException e){
                stop(target);
                String message = "Error occurred while fetching data: "+e.getMessage();
                logger.error(message, e);
                onUpdateError(target, e);
            }
        }
    }
}

I like the idea of this panel.

I was wondering is it possible to have a Wicket component updated without polling? i.e. the server can send a message back to the browser to tell it to update a panel.

Is that what Wicket's Websocket impl is designed for.