RCP中如何获取页面状态（最大/最小/restore）

       IWorkbenchPage ipage= PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage();
       IWorkbenchPartReference partRef=ipage.getActivePartReference();
       WorkbenchPage page=(WorkbenchPage)ipage;
       //获得页面状态 IStackPresentationSite.STATE_MINIMIZED
       //IStackPresentationSite.STATE_MAXIMIZED
       //IStackPresentationSite.STATE_RESTORED三种
       int state = getState(partRef, page.getActivePerspective());

    int getState(IWorkbenchPartReference ref,Perspective persp) {
   
        if (persp == null) {
   
            return IStackPresentationSite.STATE_RESTORED;
        }

        PartPane pane = ((WorkbenchPartReference) ref).getPane();

        if (ref instanceof IViewReference
                && persp.isFastView((IViewReference) ref)) {
   
            return persp.getFastViewState();
        }       

        PartStack parent = ((PartStack)pane.getContainer());

        if (parent != null) {
   
            return parent.getState();
        }

        return IStackPresentationSite.STATE_RESTORED;
    }

    public static int STATE_MINIMIZED = 0;

    public static int STATE_MAXIMIZED = 1;

    public static int STATE_RESTORED = 2;