I know it's illegal , but should this be controlled by application, insteand of throwing a exception?
>>java.lang.IllegalArgumentException: The workbook already contains a sheet of this name
>> at org.zkoss.poi.xssf.usermodel.XSSFWorkbook.setSheetName(XSSFWorkbook.java:1336)
>> at org.zkoss.zss.model.impl.XSSFBookImpl.setSheetName(XSSFBookImpl.java:246)
>> at org.zkoss.zss.model.impl.RangeImpl.setSheetName(RangeImpl.java:2374)
>> at org.zkoss.zss.ui.au.in.ActionCommand.processSheet(ActionCommand.java:87)
>> at org.zkoss.zss.ui.au.in.ActionCommand.process(ActionCommand.java:59)
>> at org.zkoss.zss.ui.Spreadsheet.service(Spreadsheet.java:4655)
>> at org.zkoss.zk.ui.impl.DesktopImpl.service(DesktopImpl.java:698)
>> at org.zkoss.zk.ui.impl.UiEngineImpl.execUpdate(UiEngineImpl.java:1194)
>> at org.zkoss.zk.au.http.DHtmlUpdateServlet.process(DHtmlUpdateServlet.java:583)
>> at org.zkoss.zk.au.http.DHtmlUpdateServlet.doGet(DHtmlUpdateServlet.java:481)
>> at org.zkoss.zk.au.http.DHtmlUpdateServlet.doPost(DHtmlUpdateServlet.java:489)
>> at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
>> at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
>> at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
>> at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:401)
>> at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
>> at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
>> at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:766)
>> at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:450)
>> at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
>> at org.mortbay.jetty.Server.handle(Server.java:326)
>> at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
>> at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:945)
>> at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:756)
>> at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218)
>> at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
>> at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:410)
>> at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)