Worker Threads and SwingWorkerWorker线程和SwingWorker

When a Swing program needs to execute a long-running task, it usually uses one of the worker threads, also known as the background threads. 当Swing程序需要执行长时间运行的任务时，它通常使用一个工作线程，也称为后台线程。Each task running on a worker thread is represented by an instance of javax.swing.SwingWorker. 在工作线程上运行的每个任务都由javax.swing.SwingWorker例表示。SwingWorker itself is an abstract class; you must define a subclass in order to create a SwingWorker object; anonymous inner classes are often useful for creating very simple SwingWorker objects.SwingWorker本身是一个抽象类；您必须定义一个子类才能创建SwingWorker对象；匿名内部类通常用于创建非常简单的SwingWorker对象。

SwingWorker provides a number of communication and control features:提供了许多通信和控制功能：

• The SwingWorker subclass can define a method, done, which is automatically invoked on the event dispatch thread when the background task is finished.SwingWorker子类可以定义一个方法done，该方法在后台任务完成时在事件分派线程上自动调用。
• SwingWorker implements java.util.concurrent.Future. 实现java.util.concurrent.Future。This interface allows the background task to provide a return value to the other thread. 此接口允许后台任务向其他线程提供返回值。Other methods in this interface allow cancellation of the background task and discovering whether the background task has finished or been cancelled.此接口中的其他方法允许取消后台任务，并发现后台任务是已完成还是已取消。
• The background task can provide intermediate results by invoking SwingWorker.publish, causing SwingWorker.process to be invoked from the event dispatch thread.后台任务可以通过调用SwingWorker.publish来提供中间结果，从而从事件分派线程调用SwingWorker.process。
• The background task can define bound properties. 后台任务可以定义绑定属性。Changes to these properties trigger events, causing event-handling methods to be invoked on the event dispatch thread.对这些属性的更改会触发事件，导致在事件分派线程上调用事件处理方法。

These features are discussed in the following subsections.这些功能将在以下小节中讨论。