XScrollBar getScrollValue and setScrollValue

Hi,

 I have being implemented A Visual Navigator for Open Office write as my
induvidual project under CS 3200 course module. I want to set  and get
scroolbar value of the currently viewing writer document. Referring
developer guide i found that i need to get
com.sun.star.awt.UnoControlScrollBarModel of the document but i don't know
hove to get this :( .As my project dead line also coming close please let me
know how to do this. my code sample is mentioned below


i am using Netbeans to implement Open Office add on with Open Office SDK


                                private final XComponentContext m_xContext;
                                private XDesktop xDesktop;
                                private Object desktop;
                                private XMultiComponentFactory xmcf;
                                private XComponent xDoc;
                                private XModel xModel;

                                xmcf = m_xContext.getServiceManager();

                                desktop =
xmcf.createInstanceWithContext("com.sun.star.frame.Desktop", m_xContext);
                               xDesktop = (XDesktop)
UnoRuntime.queryInterface(com.sun.star.frame.XDesktop.class, desktop);
                               xDoc = xDesktop.getCurrentComponent();

                             xModel =
(XModel)UnoRuntime.queryInterface(XModel.class, xDoc);
                             xController = xModel.getCurrentController();

                                      // trying to get ScrollBar
                             xScrollBar = (XScrollBar)
UnoRuntime.queryInterface(XScrollBar.class, xController);

                                      // try to control Scrollbar
                             System.out.println("ScrollValue id
"+xScrollBar.getValue());      // this gives null pointer exception when i
run this code

xScrollBar.setOrientation(xScrollBar.getMaximum());




-- 
Shameera Rathnayaka
Undergraduate
Department of Computer Science and Engineering
University of Moratuwa.
Sri Lanka.
T.P.  0719221454