Prerequisite problem

Question

I have a JSP form which list modules that student can take. Some of these modules have prerequisite and some do not.
In order to successfully register a student, I have a number of requirements e.g. must not be already register; the registration date must not have passed etc.
My problem is in my code logic. For example, when a student selects a module, which does not have a prerequisite, and a module, which has a prerequisite and click on the Register button, an Error.jsp page is displayed because he has not satisfied the prerequisite for the second module.
What the program does is that it registers the first module which dose not has a prerequisite and display the Error.jsp page.
This is confusing for the user because they expect to do the process again and do not know that the first module has been register successfully.
Here is my code
private int enroll()throws SQLException,
IOException, ServletException
// Get the check box values
String checkboxNames[] = request.getParameterValues( "checkbox" );
moduleVector = (Vector) session.getAttribute( "moduleVector" );
//Get the student bean
studentBean = (StudentBean) session.getAttribute( "studentBean" );
boolean isEnrolled = false;
String studentId = studentBean.getStudentId();
int maxModule = Integer.parseInt(studentBean.getMaxModule());
for (int i = 0; i < checkboxNames.length; i++) {
String moduleId = checkboxNames;
// First, make sure that this student is not already
// enrolled for this module, and he/she has never
// taken and passed the module before.
isEnrolled = srsBean.isEnrolledIn( moduleId, studentId );
if (isEnrolled){
session.setAttribute("pre_enrolled", moduleId);
return PREVIOUSLY_ENROLLED;
// Now we make sure that the registration date has not
// already passed
Calendar rightNow = Calendar.getInstance();
int rightNowMonth = rightNow.MONTH;
int rightNowDay = rightNow.DAY_OF_MONTH;
if ( rightNowMonth > Constants.REGISTER_DATE_MONTH ) {
return PASSED_REGISTER_DATE;
}else if( rightNowMonth == Constants.REGISTER_DATE_MONTH ) {
if ( rightNowDay > Constants.REGISTER_DATE_DAY ) {
return PASSED_REGISTER_DATE;
int noModule = srsBean.noModuleEnrolledIn( studentId );
// Now we make sure we don't erroll student on more
// modules that the are allowed to do.
if (!(noModule < maxModule)){
// convert maxModule into string so we can use setAttribute
String max = String.valueOf(maxModule);
session.setAttribute("exceed_max_no", max);
return EXCEEDED_MAX_NO_MODULE;
// if there are any prerequisites for this module, check
// to ensure that the student has completed them.
if ( srsBean.hasPrerequisites(moduleId)) {
Enumeration e = srsBean.getPrerequisites(moduleId);
while ( e.hasMoreElements() ) {
String pre = (String) e.nextElement();
// See if the Student's Transcript reflects
// successful completion of the prerequisite.
if (!srsBean.verifyCompletion(moduleId, studentId)){
session.setAttribute("prereq_not_sat", moduleId);
return PREREQ_NOT_SATISFIED;
// if we made it to here in the code, we're ready to
// officially enroll the student.
srsBean.enroll( studentId, moduleId );
return SUCCESSFULLY_ENROLLED;
How can i fix this problem ?

Answer 1

If you repost the code with &#91;code] tags, and wait more than half an hour, you have reasonable chances of getting help.