dbloadvisitor.java

《Java案例开发》源代码( 考勤系统的完整实现！） 包括数据库 网络通讯＆uml

/*
 * DBLoadVisitor.java
 *
 * Created on 2003年11月6日, 下午12:23
 */

package romulus;

import java.sql.*;

/**
 * The Visitor is used to load the full structure of the Romulus Node.
 * @author  Romulus
 * @version 1.0
 */
public class DBLoadVisitor implements Visitor {

    private Connection con = null;

    /** Creates new DBLoadVisitor */
    public DBLoadVisitor(Connection con) {
        this.con = con;
    }

    /** Visit the Content. */
    public void VisitContent(Content cont) throws SQLException, RomulusException{
        //prepare the basic structure
        int c_type = 0;
        //prepare the select sql
        int c_s_ident = RomulusToolSet.getSIdent(con, "Content", cont.getIdent());
        int c_i_s_ident = 0;
        String type_sql = "select  con_i_s_ident, con_type from contentlist where con_s_ident =?";
        String textcon_sql = "select ident, text from textcontent where s_ident =?";
        //content item type
        PreparedStatement pre = con.prepareStatement(type_sql);
        pre.setInt(1, c_s_ident);
        ResultSet res = pre.executeQuery();
        while(res.next()){
            c_i_s_ident = res.getInt(1);
            c_type = res.getInt(2);
            if(c_type == ContentItem.Int_Type_TextContent || c_type == ContentItem.Int_Type_EmTextContent){
                //text content only
                PreparedStatement pre_text = con.prepareStatement(textcon_sql);
                pre_text.setInt(1, c_i_s_ident);
                ResultSet res_text = pre_text.executeQuery();
                if(res_text.next()){
                    TextContent textcon = new TextContent(res_text.getString(1), res_text.getString(2), c_type == ContentItem.Int_Type_EmTextContent?true:false);
                    textcon.Accept(this);
                    cont.Add(textcon);
                }
            }
            else{
                throw new RomulusException(RomulusException.TypeError);
            }
        }
        res.close();
        pre.close();
    }
    
    /** Visit the Feedback. */
    public void VisitFeedback(Feedback fb) throws SQLException, RomulusException{
        //prepare the basic structure
        Content cont = null;
        //prepare the select sql
        int f_s_ident = RomulusToolSet.getSIdent(con, "Feedback", fb.getIdent());
        int con_s_ident = 0;
        String con_sql = "select ident, label from content where s_ident in "
            +"(select con_s_ident from feedback where s_ident = ?)";
        //get content
        PreparedStatement pre = con.prepareStatement(con_sql);
        pre.setInt(1, f_s_ident);
        ResultSet res = pre.executeQuery();
        if(res.next()){
            cont = new Content(res.getString(1), res.getString(2));
            cont.Accept(this);
            fb.setContent(cont);
        }
        res.close();
        pre.close();
    }
    
    /** Visit the Objective. */
    public void VisitObjective(Objective obj) throws SQLException, RomulusException{
        //prepare the basic structure
        Content cont = null;
        //prepare the select sql
        int o_s_ident = RomulusToolSet.getSIdent(con, "Objective", obj.getIdent());
        int con_s_ident = 0;
        String con_sql = "select ident, label from content where s_ident in "
            +"(select con_s_ident from objective where s_ident = ?)";
        //get content
        PreparedStatement pre = con.prepareStatement(con_sql);
        pre.setInt(1, o_s_ident);
        ResultSet res = pre.executeQuery();
        if(res.next()){
            cont = new Content(res.getString(1), res.getString(2));
            cont.Accept(this);
            obj.setContent(cont);
        }
        res.close();
        pre.close();
    }
    
    /** Visit the Question. */
    public void VisitQuestion(Question que) throws SQLException, RomulusException{
        //prepare the basic structure
        Objective obj = null;
        Feedback fb = null;
        //prepare the select sql
        int q_s_ident = RomulusToolSet.getSIdent(con, "Question", que.getIdent());
        int qitem_s_ident = 0;
        int q_type = QuestionItem.CHOICE_TYPE;
        String obj_sql = "select ident, can_view from objective where s_ident in "
            +"(select  o_s_ident from objectlist where q_s_ident =?)";
        String fb_sql = "select ident, can_view, title from feedback where s_ident in "
            +"(select  f_s_ident from feedbacklist where q_s_ident =?)";
        //objective
        PreparedStatement pre = con.prepareStatement(obj_sql);
        pre.setInt(1, q_s_ident);
        ResultSet res = pre.executeQuery();
        while(res.next()){
            obj = new Objective(res.getString(1), res.getInt(2));
            obj.Accept(this);
            que.addObjective(obj);
        }
        res.close();
        pre.close();
        //feedback
        pre =con.prepareStatement(fb_sql);
        pre.setInt(1, q_s_ident);
        res = pre.executeQuery();
        while(res.next()){
            fb = new Feedback(res.getString(1), res.getInt(2), res.getString(3));
            fb.Accept(this);
            que.addFeedback(fb);
        }
        res.close();
        pre.close();
        //get item type
        String type_sql = "select  i_s_ident, type from itemlist where q_s_ident =?";
        pre = con.prepareStatement(type_sql);
        pre.setInt(1, q_s_ident);
        res = pre.executeQuery();
        if(res.next()){
            qitem_s_ident = res.getInt(1);
            q_type = res.getInt(2);
            if(q_type == QuestionItem.FIB_TYPE){
                //fib
                String fib_sql = "select ident, maxchars, correctanswer from fib where s_ident = ? ";
                PreparedStatement pre_qitem = con.prepareStatement(fib_sql);
                pre_qitem.setInt(1, qitem_s_ident);
                ResultSet res_qitem = pre_qitem.executeQuery();
                if(res_qitem.next()){
                    FIB fib = new FIB(res_qitem.getString(1), res_qitem.getInt(2), res_qitem.getString(3));
                    fib.Accept(this);
                    que.setQuestionItem(fib);
                }
            }
            else if(q_type == QuestionItem.CHOICE_TYPE){
                //choice
                String choice_sql = "select ident, rcardinality, shuffle from choice where s_ident = ? ";
                PreparedStatement pre_qitem = con.prepareStatement(choice_sql);
                pre_qitem.setInt(1, qitem_s_ident);
                ResultSet res_qitem = pre_qitem.executeQuery();
                if(res_qitem.next()){
                    Choice ch = new Choice(res_qitem.getString(1), res_qitem.getInt(2), (res_qitem.getInt(3) == 0)?false:true);
                    ch.Accept(this);
                    que.setQuestionItem(ch);
                }
            }
            else{
                throw new RomulusException(RomulusException.TypeError);
            }
        }
        res.close();
        pre.close();
   }
    
    /** Visit the QuestionItem. */
   public void VisitQuestionItem(QuestionItem qitem) throws SQLException, RomulusException{
       if(qitem instanceof FIB){
           int fib_s_ident = RomulusToolSet.getSIdent(con, "FIB", ((FIB)qitem).getIdent());
           String con_sql = "select ident, label from content where s_ident in "
           +"(select con_s_ident from FIB where s_ident = ?)";
           //get content
           PreparedStatement pre = con.prepareStatement(con_sql);
           pre.setInt(1, fib_s_ident);
           ResultSet res = pre.executeQuery();
           if(res.next()){
               Content cont = new Content(res.getString(1), res.getString(2));
               cont.Accept(this);
               ((FIB)qitem).setContent(cont);
           }
           res.close();
           pre.close();
       }
       else if(qitem instanceof Choice){
           int choice_s_ident = RomulusToolSet.getSIdent(con, "choice", ((Choice)qitem).getIdent());
           String con_sql = "select ident, label from content where s_ident in "
           +"(select con_s_ident from choice where s_ident = ?)";
           //get content
           PreparedStatement pre = con.prepareStatement(con_sql);
           pre.setInt(1, choice_s_ident);
           ResultSet res = pre.executeQuery();
           if(res.next()){
               Content cont = new Content(res.getString(1), res.getString(2));
               cont.Accept(this);
               ((Choice)qitem).setContent(cont);
           }
           //get choiceitem
           String citem_sql = "select ident, label, iscorrect from choiceitem where s_ident in "
           +"(select ci_s_ident from choiceitemlist where c_s_ident = ?)";
           pre = con.prepareStatement(citem_sql);
           pre.setInt(1, choice_s_ident);
           res = pre.executeQuery();
           ChoiceItem citem = null;
           while(res.next()){
               citem = new ChoiceItem(res.getString(1), res.getString(2), res.getInt(3)==1?true:false);
               citem.Accept(this);
               ((Choice)qitem).addChoiceItem(citem);
           }
           res.close();
           pre.close();
       }
       else{
           throw new RomulusException(RomulusException.TypeError);
       }
   }
    
    /** Visit Test. */
    public void VisitTest(Test test) throws SQLException, RomulusException{
       //prepare the select param
        int t_s_ident = RomulusToolSet.getSIdent(con, "Test", test.getIdent());
        String sql = "select ident, title, timing from question where s_ident in "
            +"(select q_s_ident from questionlist where t_s_ident =?)";
        //search the question and add to test
        PreparedStatement pre = con.prepareStatement(sql);
        pre.setInt(1, t_s_ident);
        ResultSet res = pre.executeQuery();
        Question que = null;
         while(res.next()){
            que = new Question(res.getString(1), res.getInt(3), res.getString(2));
            que.Accept(this);
            test.add(que);
        }
        res.close();
        pre.close();
    }
    
    /** Visit the ChoiceItem. */
    public void VisitChoiceItem(ChoiceItem citem) throws SQLException, RomulusException {
        int ci_s_ident = RomulusToolSet.getSIdent(con, "choiceitem", citem.getIdent());
        String con_sql = "select ident, label from content where s_ident in "
        +"(select con_s_ident from choiceitem where s_ident = ?)";
        //get content
        PreparedStatement pre = con.prepareStatement(con_sql);
        pre.setInt(1, ci_s_ident);
        ResultSet res = pre.executeQuery();
        if(res.next()){
            Content cont = new Content(res.getString(1), res.getString(2));
            cont.Accept(this);
            citem.setContent(cont);
        }
        res.close();
        pre.close();
    }
    
    /**Visit the ContentItem.*/
    public void VisitContentItem(ContentItem citem) throws SQLException, RomulusException{
        //leaf node, no more content
    }
}