KeyboardFocusManager.java 文件源码

/**
 * Sets the active Window. Only a Frame or a Dialog can be the active
 * Window. The native windowing system may denote the active Window or its
 * children with special decorations, such as a highlighted title bar. The
 * active Window is always either the focused Window, or the first Frame or
 * Dialog that is an owner of the focused Window.
 * <p>
 * This method does not actually change the active Window as far as the
 * native windowing system is concerned. It merely stores the value to be
 * subsequently returned by {@code getActiveWindow()}. Use
 * {@code Component.requestFocus()} or
 * {@code Component.requestFocusInWindow()} to change the active
 * Window, subject to platform limitations.
 *
 * @param activeWindow the active Window
 * @see #getActiveWindow
 * @see #getGlobalActiveWindow
 * @see Component#requestFocus()
 * @see Component#requestFocusInWindow()
 * @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
 */
protected void setGlobalActiveWindow(Window activeWindow)
    throws SecurityException
{
    Window oldActiveWindow;
    synchronized (KeyboardFocusManager.class) {
        checkKFMSecurity();

        oldActiveWindow = getActiveWindow();
        if (focusLog.isLoggable(PlatformLogger.Level.FINER)) {
            focusLog.finer("Setting global active window to " + activeWindow + ", old active " + oldActiveWindow);
        }

        try {
            fireVetoableChange("activeWindow", oldActiveWindow,
                               activeWindow);
        } catch (PropertyVetoException e) {
            // rejected
            return;
        }

        KeyboardFocusManager.activeWindow = activeWindow;
    }

    firePropertyChange("activeWindow", oldActiveWindow, activeWindow);
}