package bookutil;
import javax.servlet.http.*;
/*This class is used to dispart page and elicit cookies .
 *current page is cur_page;total page is tatal_page;
 *The method :int divPage(int len,int pagesize,String curpage)
 *return the just position to be display.
 */
public class BookTools {
  public int cur_page=1;
  public int total_page=1;
  public int size_page=5;
  public BookTools() {
  }
  public int divPage(int len,int pagesize,String curpage){
    if(len<=0||pagesize<=0){
      return -1;
    }
    int rec_pos=0;
    size_page=pagesize;
    total_page=(len+pagesize-1)/pagesize;
    try{
      cur_page=Integer.parseInt(curpage);
    }catch(Exception e){
      cur_page=1;
    }
    if(cur_page<=0)cur_page=1;
    if(cur_page>total_page)cur_page=total_page;
    rec_pos=(cur_page-1)*pagesize;
    return rec_pos;
  }

  /**
   * elicitCookie
   *
   * @return Object
   */
  public static Object elicitCookie(HttpServletRequest request,String ckname)
  {
    if(request == null || ckname == null)return null;
    Cookie[] ckarray = null;
    ckarray = request.getCookies();
    for(int i = 0;i<ckarray.length;i++)
    {
       if(ckarray[i].getName().equals(ckname))
       {
          return ckarray[i].getValue();
       }
    }
    return null;
  }

}