gradevisitor.java

《Java案例开发》源代码252KB大小

/*
 * GradeVisitor.java
 *
 * Created on 2003年11月6日, 下午12:29
 */

package romulus;

import java.sql.*;
import java.util.*;

/**
 * The class for grade the score of a test.
 * Such visitor has two tasks.
 * The first is adding the correct answer and feedback.
 * And the other is set the score of the test.
 * @author  Romulus
 * @version 1.0
 */
public class GradeVisitor implements Visitor {

    private Connection con = null;

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

    /** Visit the Content. */
    public void VisitContent(Content cont) throws SQLException, RomulusException{
        //content will not be graded but should be added to the initial test (feedback will use it)
        //task 1
        //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{
        //feedback will not be graded but the feedback should be added to the initial test
        //task 1
        //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{
        //objectives have already added to the initial test
    }
    
    /** Visit the Question. */
    public void VisitQuestion(Question que) throws SQLException, RomulusException{
        //prepare the select sql
        int q_s_ident = RomulusToolSet.getSIdent(con, "Question", que.getIdent());
        String fb_sql = "select ident, can_view, title from feedback where s_ident in "
            +"(select  f_s_ident from feedbacklist where q_s_ident =?)";
        //get the feedback
        //task 1
        PreparedStatement pre =con.prepareStatement(fb_sql);
        pre.setInt(1, q_s_ident);
        ResultSet res = pre.executeQuery();
        Feedback fb = null;
        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
        //We will not get the items out but only visit them to get the correct answer
        QuestionItem qitem = que.getItem();
        qitem.Accept(this);
    }
    
    /** Visit the QuestionItem. */
    public void VisitQuestionItem(QuestionItem qitem) throws SQLException, RomulusException{
        //get correct only
        //task 1
        if(qitem instanceof FIB){
            int fib_s_ident = RomulusToolSet.getSIdent(con, "FIB", ((FIB)qitem).getIdent());
            String fib_sql = "select correctanswer from fib where s_ident = ? ";
            PreparedStatement pre_qitem = con.prepareStatement(fib_sql);
            pre_qitem.setInt(1, fib_s_ident);
            ResultSet res_qitem = pre_qitem.executeQuery();
            if(res_qitem.next()){
                ((FIB)qitem).setCorrectAnswer(res_qitem.getString(1));
            }
            res_qitem.close();
            pre_qitem.close();
       }
       else if(qitem instanceof Choice){
           //just let the choiceitem to get the correctness
           for(Iterator i = ((Choice)qitem).choiceitemIterator(); i.hasNext(); ){
               ((ChoiceItem)i.next()).Accept(this);
           }
       }
       else{
           throw new RomulusException(RomulusException.TypeError);
       }
    }
    
    /** Visit Test. */
    public void VisitTest(Test test) throws SQLException, RomulusException{
        for(Iterator i = test.questionIterator(); i.hasNext(); ){
            ((Question)i.next()).Accept(this);
        }
    }
    
    /** Visit the ContentItem. */
    public void VisitChoiceItem(ChoiceItem citem) throws SQLException, RomulusException {
        //just get the correct flag
        //task 1
        int ci_s_ident = RomulusToolSet.getSIdent(con, "choiceitem", citem.getIdent());
        String citem_sql = "select iscorrect from choiceitem where s_ident = ?";
        //get content
        PreparedStatement pre = con.prepareStatement(citem_sql);
        pre.setInt(1, ci_s_ident);
        ResultSet res = pre.executeQuery();
        if(res.next()){
            citem.setCorrect(res.getInt(1)==1?true:false);
        }
        res.close();
        pre.close();
    }
    
    /**Visit the ContentItem.*/
    public void VisitContentItem(ContentItem citem) throws SQLException, RomulusException{
        //leaf node, no more content
    }
    
    /**Get the score of the test.*/
    public static double VisitTestGetScore(Connection con, Test t) throws SQLException, RomulusException{
        t.Accept(new GradeVisitor(con));
        double corrnumber = 0;
        for(Iterator i = t.questionIterator(); i.hasNext(); ){
            if(((Question)i.next()).getItem().isCorrect()){
                corrnumber++;
            }
        }
        System.out.println(corrnumber/(t.size()));
        return corrnumber/(t.size());
    }
}