KeyboardFocusManager.java 文件源码

/**
 * Sets the focused Window. The focused Window is the Window that is or
 * contains the focus owner. The operation will be cancelled if the
 * specified Window to focus is not a focusable Window.
 * <p>
 * This method does not actually change the focused Window as far as the
 * native windowing system is concerned. It merely stores the value to be
 * subsequently returned by <code>getFocusedWindow()</code>. Use
 * <code>Component.requestFocus()</code> or
 * <code>Component.requestFocusInWindow()</code> to change the focused
 * Window, subject to platform limitations.
 *
 * @param focusedWindow the focused Window
 * @see #getFocusedWindow
 * @see #getGlobalFocusedWindow
 * @see Component#requestFocus()
 * @see Component#requestFocusInWindow()
 * @see Window#isFocusableWindow
 * @throws SecurityException if this KeyboardFocusManager is not the
 *         current KeyboardFocusManager for the calling thread's context
 *         and if the calling thread does not have "replaceKeyboardFocusManager"
 *         permission
 * @beaninfo
 *       bound: true
 */
protected void setGlobalFocusedWindow(Window focusedWindow)
    throws SecurityException
{
    Window oldFocusedWindow = null;
    boolean shouldFire = false;

    if (focusedWindow == null || focusedWindow.isFocusableWindow()) {
        synchronized (KeyboardFocusManager.class) {
            checkKFMSecurity();

            oldFocusedWindow = getFocusedWindow();

            try {
                fireVetoableChange("focusedWindow", oldFocusedWindow,
                                   focusedWindow);
            } catch (PropertyVetoException e) {
                // rejected
                return;
            }

            KeyboardFocusManager.focusedWindow = focusedWindow;
            shouldFire = true;
        }
    }

    if (shouldFire) {
        firePropertyChange("focusedWindow", oldFocusedWindow,
                           focusedWindow);
    }
}