checkmultianswersaction.java

老外的在线考试

/*
 * CyberTester - J2EE Web application for creating, delivering and managing tests/exams/surveys. 
 * Copyright (C) 2004 CyberDemia Research and Services Pty Ltd
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program (see the file COPYING); if not, write to the
 * Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * See the COPYING file located in the top-level-directory of
 * the archive of this program for complete text of license.
 */
package com.cyberdemia.cybertester.testee.test;

import javax.servlet.ServletException;
import javax.servlet.http.*;
import org.apache.struts.action.*;

import com.cyberdemia.school.*;
import com.cyberdemia.cybertester.*;
import com.cyberdemia.cybertester.testee.TesteeConstants;
import java.util.logging.*;

/**
 * 
 * CheckMultiAnswersAction is a Struts action to receive and check the user's answers
 * to all the questions. It is called once for a test that has its
 * "multiQuestionsMode" enabled.
 *  
 * @version $Revision: 1.6 $ at $Date: 2004/06/26 17:14:52 $ by $Author: alexycyap $
 * @author Alexander Yap
 */
public final class CheckMultiAnswersAction extends AbstractUserAction
{
	protected ActionForward doPerform(
		ActionMapping mapping, ActionForm form,
		HttpServletRequest request, HttpServletResponse response,
		HttpSession session) throws Exception
	{

		// Was this transaction cancelled?
		if (request.getParameter(org.apache.struts.taglib.html.Constants.CANCEL_PROPERTY)!=null)
		{
			cleanup( session );
			return mapping.findForward(Constants.CANCELLED);
		}

		ActionErrors errors = new ActionErrors();
		
		// If submitted out of order, go to error page immediately.
		if (!isTokenValid(request))
		{
			errors.add(ActionErrors.GLOBAL_ERROR, new ActionError("error.transaction.token"));
		}
		
		resetToken(request);

		boolean endOfTest = true;
		AnswerStatus status = null;
		Integer testId = (Integer)session.getAttribute(TesteeConstants.TEST_ID_KEY);
		QuestionData[] questions = (QuestionData[])session.getAttribute( TesteeConstants.QUESTION_LIST_KEY);
		Integer userId = (Integer)session.getAttribute(Constants.USER_ID_KEY);
		Integer questionOffset = (Integer)session.getAttribute(TesteeConstants.QUESTION_LIST_OFFSET_KEY);
		int nextOffset = 0;
		if (errors.isEmpty())
		{
			if ( questions==null )
			{
				throw new ServletException("Missing session attribute "+TesteeConstants.QUESTION_LIST_KEY);
			}
					
			if ( testId==null )
			{
				throw new ServletException("Missing session attribute "+TesteeConstants.TEST_ID_KEY);
			}
			
			if ( userId==null )
			{
				throw new ServletException("Missing session attribute "+Constants.USER_ID_KEY);
			}
			
			if ( questionOffset==null )
			{
				throw new ServletException("Missing session attribute "+TesteeConstants.QUESTION_LIST_OFFSET_KEY);
			}
					
			final int offset = questionOffset.intValue();
			nextOffset = offset + TesteeConstants.QUESTION_LIST_BLOCK_SIZE;
			endOfTest = (questions.length <= nextOffset);
			
			try
			{
								
				TestManagerHome testMgrHome = CyberTesterUtils.getTestManagerHome();
				TestManager testMgr = (TestManager)testMgrHome.create();
				if ((offset > 0) || !testMgr.getTestScoreForUser(testId, userId, false).isTestTaken())
				{
					int endPos = Math.min(questions.length, nextOffset);
					Integer[] quesIds = new Integer[endPos-offset];
					String[] answerStrs = new String[quesIds.length];
					for (int q=offset, i=0; q<endPos; q++, i++)
					{
						QuestionData quesData = questions[q];
						quesIds[i] = quesData.getId();
						String answerStr = null;
						if (quesData.isMultipleChoiceType())
						{
							StringBuffer answerBuf = new StringBuffer();
							int choiceCnt = quesData.getAnswerChoices().length;
							boolean anyTicked = false;
							for (int c=0; c<choiceCnt; c++)
							{
								boolean ticked = Boolean.valueOf(request.getParameter("answer_"+q+"_"+c)).booleanValue();
								if (ticked)
								{
									if (anyTicked)
									{
										answerBuf.append(",");
									}
									else
									{
										anyTicked = true;										
									}
									answerBuf.append(c);
								}
							}	
							
							if (!anyTicked)
							{
								errors.add("MissingAnswer"+q, new ActionError("error.form.missingParam.selectMultiple","Answer "+q));
							}
							answerStr = answerBuf.toString();
						}
						else
						{
							answerStr = request.getParameter("answer_"+q);
							if ((answerStr==null) || (answerStr.trim().length()==0) )
							{
								if (quesData.isSingleChoiceType())
								{
									errors.add("MissingAnswer"+q, new ActionError("error.form.missingParam.select","Answer "+q));
								}
								else
								{
									errors.add("MissingAnswer"+q, new ActionError("error.form.missingParam.enter","Answer "+q));
								}
							}
						}
						
						answerStrs[i] = answerStr;
						
					} // end of for...
					
					if (errors.isEmpty())
					{
						// Skip time check if test is not ended yet.
						int timeSecs = (endOfTest) ? (int)(TesteeTestUtils.checkTestTimeToken(session,testId)/1000) : 0;
						status = testMgr.checkMultiQuestionAnswers(testId, quesIds, userId, offset, answerStrs, timeSecs, endOfTest);
					}
				}
				else
				{
					CyberTesterUtils.getLogger().log( Level.WARNING, "User "+userId+" already taken test "+testId);
					errors.add(ActionErrors.GLOBAL_ERROR, new ActionError("error.test.taken"));
				}
			}
			catch (Exception ex)
			{
				CyberTesterUtils.getLogger().log( Level.SEVERE, "Error checking answers.", ex);
				errors.add(ActionErrors.GLOBAL_ERROR, new ActionError("error.checking.answers",ex.getMessage()));
			}

		}

		if (!errors.isEmpty())
		{
			// Force cleanup even if test not ended yet when there is an error.
			cleanup(session);			
			saveErrors(request, errors);
			return mapping.findForward(Constants.ERROR);
		}

		// End of the test, clean up the session
		if (endOfTest)
		{
			cleanup(session);
		}
		else
		{	// Test not yet ended, go to next offset.
			session.setAttribute(TesteeConstants.QUESTION_LIST_OFFSET_KEY, new Integer(nextOffset));
			request.setAttribute(TesteeConstants.QUESTION_LIST_BLOCK_END_INDEX_KEY, new Integer(Math.min( nextOffset+TesteeConstants.QUESTION_LIST_BLOCK_SIZE, questions.length )-1));
			// Set a transactional control token to prevent double posting
			saveToken(request);
		}

		request.setAttribute( TesteeConstants.TEST_ID_KEY,testId);
		if (status.isTestTimedOut())
		{
			request.setAttribute(TesteeConstants.TEST_TIMED_OUT_KEY, Boolean.TRUE);
		}
		return mapping.findForward( endOfTest ? Constants.SUCCESS : "nextPage");
		
	}

	private void cleanup(HttpSession session)
	{
		session.removeAttribute(TesteeConstants.TEST_ID_KEY);
		session.removeAttribute(TesteeConstants.TEST_DATA_KEY);
		session.removeAttribute(TesteeConstants.QUESTION_LIST_KEY);
		session.removeAttribute(TesteeConstants.QUESTION_COUNT_KEY);
		session.removeAttribute(TesteeConstants.QUESTION_LIST_OFFSET_KEY);

		TesteeTestUtils.removeTestTimeToken(session);
	}

}