anchor.diff:           if( wiki.pageExists( pagereq ) )
            {
                %>
  -             Difference between revision <%=ver1%> and <%=ver2%>
  +             Difference between revision <%=versionDescription1%> and <%=versionDescription2%>
                <P>
                <PRE>
   <%=wiki.getDiff( pagereq, ver2, ver1 )%>
  
positive.code: 
      String pageurl = wiki.encodeName( pagereq );    
  
      String srev1 = request.getParameter("r1");
      String srev2 = request.getParameter("r2");
  
      if( srev1 == null || srev2 == null )
      {
          throw new ServletException("Empty parameters given to Diff.jsp");
      }    
  
      int ver1 = Integer.parseInt( srev1 );
      int ver2 = Integer.parseInt( srev2 );
  
      log.debug("Request for page diff for '"+pagereq+"' from "+request.getRemoteHost()+" by "+request.getRemoteUser()+".  R1="+ver1+", R2="+ver2 );
  
  
negative.code:     {
          wiki = WikiEngine.getInstance( getServletConfig() );
      }
  
      String getVersionText( int ver )
      {
          return ver > 0 ? ("version "+ver) : "current version";
      }
  
      Category log = Category.getInstance("JSPWiki"); 
      WikiEngine wiki;
  %>
  