javafx，如何实现confirmHandler？

我正在使用 javafx 的网络引擎来显示网页。在页面上，有一个脚本调用window.confirm。我已经知道如何设置确认处理程序以及如何显示类似模式的对话框。

我的问题是如何在处理程序返回之前获得用户的选择？

webEngine.setConfirmHandler(new Callback<String, Boolean>() {
@Override
public Boolean call(String message) {
// Show the dialog
...
return true; // How can I get user's choice here?
}
});

如中所述javafx-jira.kenai.com/browse/RT-19783，我们可以使用 JavaFx 2.2 中提供的新方法 showAndWait 来实现此目的。

舞台等级：

/** 
 * Show the stage and wait for it to be closed before returning to the 
 * caller. This must be called on the FX Application thread. The stage 
 * must not already be visible prior to calling this method. This must not 
 * be called on the primary stage. 
 * 
 * @throws IllegalStateException if this method is called on a thread 
 * other than the JavaFX Application Thread. 
 * @throws IllegalStateException if this method is called on the 
 * primary stage. 
 * @throws IllegalStateException if this stage is already showing. 
 */ 
public void showAndWait();

@jewelsea 创建了一个示例https://gist.github.com/2992072。谢谢！