CS320 S05 Lab1

Lab 1. Beans, EL, and JSTL
CS320, Spring 2005

[Q&A] (5pt) Please write down your answers to the following questions on a piece of paper, and show it to the instructor before you proceed to the Programming section.

1. In which directory should you put your JSP files

on your own computer?
on the CS server?

2. Suppose a bean belongs to the package cs320.stuxx. In which directory on the CS server should you put the .class file of the bean so your JSP pages can use it?

3. A bean is said to have a write-only property foo, a read-only property bar, and a read/write property fooBar. All properties are of String type. What are the headers of the getter and/or setter methods for these properties?

4. What's the difference between the following two lines of code:

<jsp:setProperty name="fb" property="user" value="user" />
<jsp:setProperty name="fb" property="user" param="user" />

5. How do you access the value of a bean property user in a JSP using EL?

6. How do you access the value of a request parameter user in a JSP using EL? and how do you check whether the parameter value is null or an empty string?

7. What is the URL to the JSTL Tag Reference documentation?

8. Give an example of using <c:forTokens>.

[Programming] (5pt) Please upload your files using the online turnin server. The files should include all the source code, documentation, and an HTML file lab1.html, which contains a link to your JSP page on the CS server. Note that file uploading will be disabled automatically after 7:40PM, so please turn in your work on time.

Problem Description. For this problem you are going to implement an simple course planner using JSP. The course planner works as follows:

Read a list of courses and their prerequisites from a text file courses.txt (compiled from CS Undergraduate Course Flow Chart). Each line in the file shows a course and its prerequisites in the format "course prereq1 prereq2 ...". Note that some courses like CS101 or CS120 do not have prerequisites.
Read a list of courses that will be offered by quarter from another text file offerings.txt (compiled from CS Course Scheduling Pattern). Each line in the file shows the list of courses that are offered in a quarter. There are four lines in the file, representing fall, winter, spring, and summer quarter, respectively.
Display a list of all the courses, and let a user to choose the courses he or she has taken.
Based on the prerequisites and the courses that will be offered, display the courses the user can take in the next quarter (the summer quarter).

Implementation Details.

1. Implement a CoursePlanner class which consists of at least the following methods:

public CoursePlanner()
public List<String> getCourses() or public Set<String> getCourses()
public void setCoursesTaken( String[] coursesTaken )
public List<String> getCoursesToTake() or public Set<String> getCoursesToTake()

2. Create a JSP page which uses a session scope bean of the CoursePlanner class. When the page is requested without any parameter, it displays the list of all courses and let a user to choose which courses he or she has taken. After the user makes the selection and hit the Submit button, the JSP page displays the list of courses the user can take in the summer quarter, as shown below (for simplicity, only a few courses are listed):

When the page is requested without any parameter:	The user selects CS120, CS202, and MATH207:	After the user clicks Submit:
Please select the courses you have taken: CS101 CS120 CS122 CS201 CS202 MATH207 ...	Please select the courses you have taken: CS101 CS120 CS122 CS201 CS202 MATH207 ...	You may take the following courses in the summer quarter: CS101 CS122 CS203

Note that in the example above, although the student has fulfilled the prerequisite for CS245, they cannot take the course because it is not offered in the summer.

No scripting elements are allowed in the JSP page.

[HINTS]

Make good use of the collection classes in Java such as maps, lists, and sets. Methods such as contains() and containsAll() in the collection classes can greatly reduce the complexity of your code.
You can test whether the bean works correctly without the JSP page. e.g.

public class CoursePlanner {

// constructors and methods

// test code

public static void main( String args[] )

{
CoursePlanner cp = new CoursePlanner();

// some tests

}

}

Note that the time of the lab is limited so don't go overboard with the testing.

Both courses.txt and offerings.txt are available under /tmp on the CS server.

[Discussion]

Our simple course planner does not validate user input, e.g. in our example above, the user indicates that he or she has taken CS202 but not CS201, which supposedly should not happen. How do you modify your code to deal with this problem?
How do you extend the simple course planner so that it not only plans for the next quarter, but also quarters ahead until all courses are planned or the unit requirement is met?