scheduler class的用法和樣例：
例句
- The plug-in utility class would listen for events from this button.
插件實(shí)用程序類(lèi)將偵聽(tīng)來(lái)自這個(gè)按鈕的事件。 - Our application class instantiates the Frame object we just designed, renders it to the screen, and sets it as the top-most window of our application.
我們的應用程序類(lèi)實(shí)例化了一個(gè)剛才設計的框架對象，把它繪制在屏幕上，并設置成程序的頂層窗口。
