为什么Swing线程模型被认为是错误的，应该如何？ [英] Why is Swing threading model considered wrong and how should it be?

问题描述

我多次听说Java Swing线程模型是错误的。我不完全理解为什么，我知道这个问题与你可以从主UI线程以外的另一个线程中绘制 Drawable 的事实有关。我知道有一些实用功能，比如 SwingUtilities.invokeAndWait 和 SwingUtilities.invokeLater 可以让你在 Runnable ，它又由Event Dispatcher线程运行。我猜这种方式可以确保绘画是同步完成的，这不会使缓冲区处于不稳定的状态。

I heard many times that Java Swing threading model is wrong. I don't fully understand why, I know that the problem is related to the fact that you can draw on a Drawable from another thread other than the main UI thread. I know that there are utility functionalities like SwingUtilities.invokeAndWait and SwingUtilities.invokeLater that let you do your painting in a Runnable, that in turn is run by the Event Dispatcher thread. I guess that this way you ensure that painting is done synchronously and this doesn't leave the buffer in an incosistent state.

我的问题是：好的UI工具包的行为如何？采用了哪些解决方案？

My question is: how do "good" UI toolkits behave? What solutions are adopted?

推荐答案

Brian Goetz的 Java实践中的并发性，

Brian Goetz's Java Concurrency in Practice,

9.1为什么GUI是单线程的？：

...在过去，GUI应用程序是单线程的，GUI事件
是从主事件循环处理的。现代GUI框架使用的
模型略有不同：它们创建一个专用事件
调度线程（EDT）来处理GUI事件。单线程GUI
框架并不是Java独有的; Qt，NextStep，MacOS Cocoa，X
Windows以及许多其他人也是单线程的。这不是
缺乏尝试;已经有很多尝试编写多线程的
GUI框架，但由于种族
条件和死锁的持续问题，他们最终都到达了
单线程事件队列模型，其中有一个专用线程从队列中获取
事件并将它们分派给应用程序定义的事件
处理程序...

...In the old days, GUI applications were single-threaded and GUI events were processed from a "main event loop". Modern GUI frameworks use a model that is only slightly different: they create a dedicated event dispatch thread (EDT) for handling GUI events. Single-threaded GUI frameworks are not unique to Java; Qt, NextStep, MacOS Cocoa, X Windows, and many others are also single-threaded. This is not for lack of trying; there have been many attempts to write multithreaded GUI frameworks, but because of persistent problems with race conditions and deadlock, they all eventually arrived at the single-threaded event queue model in which a dedicated thread fetches events off a queue and dispatches them to application-defined event handlers...

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