創建自定義工具包時，為什么createFrame在OSX上失敗？

Question

我們正在嘗試擴展UISpec4j測試框架以在運行測試時顯示用戶界面。 因此，我們有一個自定義工具包，該工具包包裝了相關平台的本機工具包。 我們設法在Windows XP上使一切正常運行，但是在OSX上測試更改時，我們的createFrame擴展似乎表現得很奇怪：

 public FramePeer createFrame(Frame target) {
   FramePeer resultc = new UISpecFramePeer(target);
   //super.createFrame(target);

   return resultc;
 }

從本質上講，我們想創建一個UISpecFramePeer作為攔截類...，以便UISpec4j可以詢問UI中發生的事情。 但是在我們的更改中，我們還希望顯示UI。 因此，我們嘗試通過使用本機工具包創建框架並將其包裝在UISpecFramePeer中（上面的代碼未顯示）來進行嘗試。

當我們運行上面的代碼時，測試將運行（正如我們期望的那樣），但是顯然沒有顯示任何內容。 但是，當我們包含super.createFrame（target）時。 我們得到以下異常：

SEVERE: Application class org.openshapa.OpenSHAPA failed to launch
java.lang.ClassCastException: org.uispec4j.interception.toolkit.UISpecFramePeer
    at apple.awt.CWindow$8.convertJComponentToTarget(CWindow.java:236)
    at apple.awt.CWindow$8.convertJComponentToTarget(CWindow.java:233)
    at apple.awt.ClientPropertyApplicator.attachAndApplyClientProperties(ClientPropertyApplicator.java:24)
    at apple.awt.CWindow$1.propertyChange(CWindow.java:190)
    at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:333)
    at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:341)
    at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:270)
    at java.awt.Component.firePropertyChange(Component.java:7277)
    at javax.swing.JComponent.addNotify(JComponent.java:4479)
    at javax.swing.JRootPane.addNotify(JRootPane.java:680)
    at java.awt.Container.addNotify(Container.java:2544)
    at java.awt.Window.addNotify(Window.java:467)
    at java.awt.Frame.addNotify(Frame.java:501)
    at java.awt.Window.pack(Window.java:485)
    at org.jdesktop.application.SingleFrameApplication.initRootPaneContainer(SingleFrameApplication.java:216)
    at org.jdesktop.application.SingleFrameApplication.show(SingleFrameApplication.java:463)
    at org.openshapa.OpenSHAPA.startup(OpenSHAPA.java:444)
    at org.jdesktop.application.Application$1.run(Application.java:171)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:461)
    at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:269)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:190)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:184)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:176)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:110)
Exception in thread "AWT-EventQueue-2" java.lang.Error: Application class org.openshapa.OpenSHAPA failed to launch
    at org.jdesktop.application.Application$1.run(Application.java:177)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:461)
    at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:269)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:190)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:184)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:176)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:110)
Caused by: java.lang.ClassCastException: org.uispec4j.interception.toolkit.UISpecFramePeer
    at apple.awt.CWindow$8.convertJComponentToTarget(CWindow.java:236)
    at apple.awt.CWindow$8.convertJComponentToTarget(CWindow.java:233)
    at apple.awt.ClientPropertyApplicator.attachAndApplyClientProperties(ClientPropertyApplicator.java:24)
    at apple.awt.CWindow$1.propertyChange(CWindow.java:190)
    at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:333)
    at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:341)
    at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:270)
    at java.awt.Component.firePropertyChange(Component.java:7277)
    at javax.swing.JComponent.addNotify(JComponent.java:4479)
    at javax.swing.JRootPane.addNotify(JRootPane.java:680)
    at java.awt.Container.addNotify(Container.java:2544)
    at java.awt.Window.addNotify(Window.java:467)
    at java.awt.Frame.addNotify(Frame.java:501)
    at java.awt.Window.pack(Window.java:485)
    at org.jdesktop.application.SingleFrameApplication.initRootPaneContainer(SingleFrameApplication.java:216)
    at org.jdesktop.application.SingleFrameApplication.show(SingleFrameApplication.java:463)
    at org.openshapa.OpenSHAPA.startup(OpenSHAPA.java:444)
    at org.jdesktop.application.Application$1.run(Application.java:171)
    ... 7 more

為什么簡單地使用本機工具包創建框架（但不返回框架）會產生異常，而在對super.createFrame進行注釋時，框架會像正常情況一樣工作？

Answer 1

我沒有在OSX上工作，但同樣的問題也會在Windows上發生，原因是：

當您執行super.createFrame() ，實際上是在創建本機對等體，該對等體最終試圖顯示，因此調用了addNotify方法。 現在內部有很多直接將對等方轉換為WFramePeer的方法（在Windows中，OSX可能是CWindowPeer或其他任何方法），因此是ClassCastException。 就您而言，我的猜測是，類CWindow試圖將您的UISpecFramePeer to WFramePeer(or CFramePeer or whatever) 。 只需通過反編譯檢查CWindow代碼並檢查即可。 請不要忘記發表您的發現。