Question

CS 2050 – Programming Project # 1

Due Date: Session 3 (that is, in one week!). Can be resubmitted up to two times until Session 6 if your first version is submitted by session 3.

In this project, you create two classes for tracking students. One class is the Student class that holds student data; the other is the GradeItem class that holds data about grades that students earned in various courses.

Note: the next three projects build on this one. To keep pace in the course, you should complete this project in full by the due date. Ask questions if you’re stuck!

Use Javadoc parameters @author, @version, @param and @return, as needed.

Problem Scenario

State University needs a Java programmer to assist it with creating a grade book application. You have graciously volunteered to help. The university wants to track their students and their grades in various courses. For each student, the university wants to track this information:

1. Student id (String – a unique value for each student)
2. Student first name (String)
3. Student last name (String)
4. Student email address (String – a unique value for each student)

The university wants to make sure that they have a correct email address for each student. They want you to verify there is an “@” in the email address.

For each grade item, the university wants to track this information:

1. Student id (String – should match a student in the student list)
2. GradeItem id (Integer – a unique value for each grade item)
3. Course id (String)
4. Item type (String – must be one of the following: HW, Quiz, Class Work, Test, Final)
5. Date (String – format yyyymmdd)
6. Maximum score (Integer – must be greater than 0)
7. Actual score (Integer – must be in the range of 0 to maximum score)

Program Requirements

Create two classes for the problem scenario given above. The classes are:

1. A Student class
2. A GradeItem class

These two classes are used in subsequent projects to instantiate the Student and GradeItem objects, and do not contain a main method or any input/output code. After declaring your instance variables, your Student and GradeItem classes should each contain these methods in this order:

1. Constructor
2. Get methods for each private variable (“getters”)
3. An equals method to determine whether two instances of an object contain exactly the same data
4. A toString method to display an instance of an object

Note: We assume that our objects are immutable (unchanged once an object is instantiated) so we don’t need any set (“setter”) methods.

Constructors in each class should validate the data as follows:

1. In the Student class
   • Ensure all values for String fields are not blank. These are the student id, first name, last name and email address.
   • Ensure the student email address contains the “@” character. Hint: Use the contains method in the String class.
2. In the GradeItem class
   • Ensure all values for String fields are not blank. These are the student id, course id, item type and date.
   • All grade item types must be one of the following: HW, Quiz, Class Work, Test, or Final. Use an array to store the types and search that array for a valid type. The entries are case‑sensitive (“HW” does not equal “Hw”). Do not hard-code the grade item types.
   • GradeItem class: Maximum score must be greater than 0.
   • GradeItem class: Actual score must be in the range of 0 to maximum score.

If any of the data in either class is invalid, the constructor in which the error was detected must throw the IllegalArgumentException exception with a message that is meaningful to a non-technical user.

Note: The data required to initialize the fields is passed by a method (defined in a subsequent project) to the constructor using arguments. In the Student and GradeItem classes, do not display any error messages on the console or in a window, or use the Scanner class to ask users for input.

Testing

We will write code to test the data in the Student and GradeItem classes in Programming Project # 2. Other than the testing described above, there is no additional testing now.

What to Submit

Submit printed copies of the Student class on top of the GradeItem class and staple them together. Write your name and Project #1 in the upper right-hand corner of the first page. Resubmitting? Place the earlier submission(s) at the end and indicate on the top page of the new submission that you are resubmitting.

Answer 1

/**
* @author Author Name
* @version Version Number
*/
class Student
{
// Private Instance variables of the class Student
private String StudentId;
private String FirstName;
private String LastName;
private String EmailId;
  
// Constructor - to validate all the fields of the class when an object gets instantiated
public Student(String studentid,String firstname,String lastname,String emailid){
  
// Try..catch block is used to handle the IllegalArgumentException
try{
  
// the first four If conditions check if the fields StudentId, Firstname, Lastname, EmailId are blank.
// If so, it raises an exception.
if(studentid.equals(" "))
throw new IllegalArgumentException("Student ID is blank");
if(firstname.equals(" "))
throw new IllegalArgumentException("First Name is blank");
if(lastname.equals(" "))
throw new IllegalArgumentException("Last Name is blank");
if(emailid.equals(" "))
throw new IllegalArgumentException("Email ID is blank");
  
// the condition checks if the @ symbol is present in the email address to validate the same.
if(emailid.contains("@")==false)
throw new IllegalArgumentException("Email ID is invalid");
  
// if all the above conditions are valid, the object gets created and the values are assigned to the variables
else
{
StudentId = studentid;
FirstName = firstname;
LastName = lastname;
EmailId = emailid;
}
  
}catch(IllegalArgumentException ex) {} // the excpetion must be caught or it will result in compilation error
}
  
//public getters for the private instance variables
public String getStudentId(){
return StudentId;
}
public String getFirstName(){
return FirstName;
}
public String getLastName(){
return LastName;
}
public String getEmailId(){
return EmailId;
}
/**
* @param s1 the first Student object to compare with
* @param s2 the second Student object to compare with
* @return true/false indicating if the objects are equal or not.
*/
public boolean equals(Student s1,Student s2)
{
if(s1.equals(s2))
return true;
else
return false;
}
  
//Method toString() is to print the student record in neat format
public String toString(){

String s = "STUDENT INFORMATION \n";
s = s + "First Name : " + FirstName + "\n";
s = s + "Last Name : " + LastName + "\n";
s = s + "Student Id : " + StudentId + "\n";
s = s + "Email Id : " + EmailId + "\n";
  
return s;
}
  
}
class GradeItem
{
// Private Instance variables of the class GradeItem
private String StudentId;
private int ItemId;
private String CourseId;
private String ItemType;
private String GradeDate;
private int MaxScore;
private int ActualScore;
  
// Constructor - to validate all the fields of the class when an object gets instantiated
public GradeItem(String studentid,int itemid,String courseid,String itemtype,String gradedate,int maxscore,int actualscore){
try{
String[] gradetypes = {"HW","Quiz","Class Work","Test","Final"};
  
// the first four If conditions check if the fields StudentId, CourseId, ItemType, GradeDate are blank.
// If so, it raises an exception.
if(studentid.equals(" "))
throw new IllegalArgumentException("Student ID is blank");
if(courseid.equals(" "))
throw new IllegalArgumentException("Course ID is blank");
if(itemtype.equals(" "))
throw new IllegalArgumentException("Item Type is blank");
if(gradedate.equals(" "))
throw new IllegalArgumentException("Date is blank");
  
// the for loop checks each valid type with the GradeType and raises an exception if it is invalid.   
// a variable found is set to false..if a match is identified in the for loop , it sets found variable to true and quits
// if found is false, then an exception is raised.
boolean found=false;
for(String type: gradetypes){
if(type.equals(itemtype))
{
found=true;
break;
}
else
found=false;
}
if (found==false)
throw new IllegalArgumentException("The Item Type is invalid");
  
// raising exception if MaxScore is less or equal to zero.
if(maxscore<=0)
throw new IllegalArgumentException("Max Score must be greater than zero");

// raising exception if ActualScore must be between 0 and maxscore.
if((actualscore<0)||(actualscore>maxscore))
throw new IllegalArgumentException("Max Score must be between 0 and " + maxscore);
  
// if all the above conditions are valid, the object gets created and the values are assigned to the variables
else
{
StudentId = studentid;
ItemId = itemid;
CourseId = courseid;
ItemType = itemtype;
GradeDate = gradedate;
MaxScore = maxscore;
ActualScore = actualscore;
}   
}catch(IllegalArgumentException ex) {}
}
  
//public getters for the private instance variables
public String getStudentId(){
return StudentId;
}
public String getCourseId(){
return CourseId;
}
public String getItemType(){
return ItemType;
}
public String getGradeDate(){
return GradeDate;
}
public int getItemId(){
return ItemId;
}
public int getMaxScore(){
return MaxScore;
}
public int getActualScore(){
return ActualScore;
}
  
/**
* @param g1 the first GradeItem object to compare with
* @param g2 the second GradeItem object to compare with
* @return true/false indicating if the objects are equal or not.
*/
public boolean equals(GradeItem g1,GradeItem g2)
{
if(g1.equals(g2))
return true;
else
return false;
}
  
//Method toString() is to print the Grade record in neat format
public String toString(){

String s = "GRADE INFORMATION \n";
s = s + "Student Id : " + StudentId + "\n";
s = s + "Item Id : " + ItemId + "\n";
s = s + "Course Id : " + CourseId + "\n";
s = s + "Item Type : " + ItemType + "\n";
s = s + "Date : " + GradeDate + "\n";
s = s + "Max. Score : " + MaxScore + "\n";
s = s + "Actual Score : " + ActualScore + "\n";
return s;
}
}

//To customize the displayed message , the IllegalArgumentException is implemented.
class IllegalArgumentException extends Exception
{
public IllegalArgumentException(String s)
{
super(s);
}
}

===============================================================================

Sample output: ( hint : used System.out.println() in toString() method just to show sample output here

STUDENT INFORMATION
First Name : aaa
Last Name : laaa
Student Id : s01
Email Id : [email protected]

GRADE INFORMATION
Student Id : s01
Item Id : 45
Course Id : c87
Item Type : HW
Date : 20190202
Max. Score : 100
Actual Score : 78

=================================================================================

Best Wishes....