how to use MessageBox to show on the time of transfering a method

[jerome1985]

final MessageBox box = MessageBox.wait("Progress", "Saving your data, please wait...",
"Saving...");
Timer t = new Timer() {
@Override
public void run() {
Info.display("Message", "Your fake data was saved", "");
box.close();
}
};
t.schedule(5000);

wcmServiceAsync.revertContentList(list, false, new AsyncCallback<Boolean>() {
public void onFailure(Throwable throwable) {
com.google.gwt.user.client.Window.alert("移除文章到垃圾箱异步调用失败");
}

public void onSuccess(Boolean aBoolean) {
if (aBoolean == true) {
AppEvent evt = new AppEvent(AppEvents.CONTENT_PUBLISH_SUC);
forwardToView(contentPublishView, evt);
} else {
com.google.gwt.user.client.Window.alert("移除文章到垃圾箱失败");
}
}
});

when i want to get the time of wcmServiceAsync.revertContentList(),so let MessageBox to show on ,how to do with this?
thanks