www.pudn.com > SRS.rar > Student.java
// Student.java - Chapter 16 version.
// Copyright 2000 by Jacquie Barker - all rights reserved.
// A MODEL class.
import java.io.*;
import java.util.*;
public class Student extends Person {
//------------
// Attributes.
//------------
private String major;
private String degree;
private Transcript transcript;
private Vector attends; // of Sections
// This next attribute was added for use with the GUI.
private String password;
//----------------
// Constructor(s).
//----------------
public Student(String ssn) {
// First, construct a "dummy" Student object. Then,
// attempt to pull this Student's information from the
// appropriate file (ssn.dat: e.g., 111-11-1111.dat).
// The file consists of a header record, containing
// the student's basic info. (ssn, name, etc.), and
// 0 or more subsequent records representing a list of
// the sections that he/she is currently registered for.
this();
String line = null;
BufferedReader bIn = null;
boolean outcome = true;
String pathToFile = ssn + ".dat";
try {
// Open the file.
bIn = new BufferedReader(new FileReader(pathToFile));
// The first line in the file contains the header info.
line = bIn.readLine();
if (line != null) parseData(line);
// Any remaining lines contain section references.
// Note that we must instantiate an empty vector
// so that the parseData2() method may insert
// items into the Vector.
attends = new Vector();
line = bIn.readLine();
while (line != null) {
parseData2(line);
line = bIn.readLine();
}
bIn.close();
}
catch (FileNotFoundException f) {
// Since we are encoding a "dummy" Student to begin
// with, the fact that his/her name will be equal
// to "???" flags an error. We have included
// a boolean method successfullyInitialized()
// which allows client code to verify the success
// or failure of this constructor (see code below).
}
catch (IOException i) {
// See comments for FileNotFoundException above.
}
// Initialize the password to be the first three digits
// of the student's ssn.
setPassword(getSsn().substring(0, 3)); // added for GUI purposes
// Create a brand new Transcript.
// (Ideally, we'd read in an existing Transcript from
// a file, but we're not bothering to do so in this
// example).
setTranscript(new Transcript(this));
}
// A second form of constructor, used when a Student's data
// file cannot be found for some reason.
public Student() {
// Reuse the code of the parent's constructor.
// Question marks indicate that something went wrong!
super("???", "???");
setMajor("???");
setDegree("???");
// Placeholders for the remaining attributes (this
// Student is invalid anyway).
setPassword("???"); // added for GUI purposes
setTranscript(new Transcript(this));
attends = new Vector();
}
//-----------------
// Get/set methods.
//-----------------
public void setMajor(String major) {
this.major = major;
}
public String getMajor() {
return major;
}
public void setDegree(String degree) {
this.degree = degree;
}
public String getDegree() {
return degree;
}
public void setTranscript(Transcript t) {
transcript = t;
}
public Transcript getTranscript() {
return transcript;
}
// This next method was added for use with the GUI.
public void setPassword(String pw) {
password = pw;
}
// This next method was added for use with the GUI.
public String getPassword() {
return password;
}
//-----------------------------
// Miscellaneous other methods.
//-----------------------------
// Used for testing purposes.
public void display() {
// First, let's display the generic Person info.
super.display();
// Then, display Student-specific info.
System.out.println("Student-Specific Information:");
System.out.println("\tMajor: " + getMajor());
System.out.println("\tDegree: " + getDegree());
displayCourseSchedule();
printTranscript();
}
// We are forced to program this method because it is specified
// as an abstract method in our parent class (Person); failing to
// do so would render the Student class abstract, as well.
//
// For a Student, we wish to return a String as follows:
//
// Joe Blow (123-45-6789) [Master of Science - Math]
public String toString() {
return getName() + " (" + getSsn() + ") [" + getDegree() +
" - " + getMajor() + "]";
}
public void displayCourseSchedule() {
// Display a title first.
System.out.println("Course Schedule for " + getName());
// Step through the Vector of Section objects,
// processing these one by one.
if (attends.size() == 0)
System.out.println("\t(none)");
else for (int i = 0; i < attends.size(); i++) {
Section s = (Section) attends.elementAt(i);
// Since the attends Vector contains Sections that the
// Student took in the past as well as those for which
// the Student is currently enrolled, we only want to
// report on those for which a grade has not yet been
// assigned.
if (s.getGrade(this) == null) {
System.out.println("\tCourse No.: " +
s.getRepresentedCourse().getCourseNo());
System.out.println("\tSection No.: " +
s.getSectionNo());
System.out.println("\tCourse Name: " +
s.getRepresentedCourse().getCourseName());
System.out.println("\tMeeting Day and Time Held: " +
s.getDayOfWeek() + " - " +
s.getTimeOfDay());
System.out.println("\tRoom Location: " +
s.getRoom());
System.out.println("\tProfessor's Name: " +
s.getInstructor().getName());
System.out.println("\t-----");
}
}
}
public void addSection(Section s) {
attends.addElement(s);
}
public void dropSection(Section s) {
attends.remove(s);
}
// Determine whether the Student is already enrolled in THIS
// EXACT Section.
public boolean isEnrolledIn(Section s) {
if (attends.contains(s)) return true;
else return false;
}
// This next method was added for use with the GUI.
// Determine whether the Student is already enrolled in ANOTHER
// Section of this SAME Course.
public boolean isCurrentlyEnrolledInSimilar(Section s1) {
boolean foundMatch = false;
Course c1 = s1.getRepresentedCourse();
Enumeration e = getEnrolledSections();
while (e.hasMoreElements()) {
Section s2 = (Section) e.nextElement();
Course c2 = s2.getRepresentedCourse();
if (c1 == c2) {
// There is indeed a Section in the attends()
// Vector representing the same Course.
// Check to see if the Student is CURRENTLY
// ENROLLED (i.e., whether or not he has
// yet received a grade). If there is no
// grade, he/she is currently enrolled; if
// there is a grade, then he/she completed
// the course some time in the past.
if (s2.getGrade(this) == null) {
// No grade was assigned! This means
// that the Student is currently
// enrolled in a Section of this
// same Course.
foundMatch = true;
break;
}
}
}
return foundMatch;
}
public void printTranscript() {
getTranscript().display();
}
public void parseData(String line) {
// We're going to parse tab-delimited records into
// four attributes -- ssn, name, major, and degree.
// First, make a copy of the record.
String restOfLine = line;
int index = restOfLine.indexOf("\t");
setSsn(restOfLine.substring(0, index));
restOfLine = restOfLine.substring(index+1);
index = restOfLine.indexOf("\t");
setName(restOfLine.substring(0, index));
restOfLine = restOfLine.substring(index+1);
index = restOfLine.indexOf("\t");
setMajor(restOfLine.substring(0, index));
setDegree(restOfLine.substring(index+1));
}
public void parseData2(String line) {
// The full section number is a concatenation of the
// course no. and section no., separated by a hyphen;
// e.g., "ART101 - 1".
String fullSectionNo = line.trim();
Section s = SRS.scheduleOfClasses.findSection(fullSectionNo);
// Note that we are using the Section class's enroll()
// method to ensure that bidirectionality is established
// between the Student and the Section.
s.enroll(this);
}
// Used after the constructor is called to verify whether or not
// there were any file access errors.
public boolean successfullyInitialized() {
if (getName().equals("???")) return false;
else return true;
}
// This method writes out all of the student's information to
// his/her ssn.dat file when he/she logs off.
public boolean persist() {
FileOutputStream fos = null;
PrintWriter pw = null;
try {
// Attempt to create the ssn.dat file. Note that
// it will overwrite one if it already exists.
fos = new FileOutputStream(getSsn() + ".dat");
pw = new PrintWriter(fos);
// First, we output the header record as a tab-delimited
// record.
pw.println(getSsn() + "\t" + getName() + "\t" +
getMajor() + "\t" + getDegree());
// Then, we output one record for every Section that
// the Student is enrolled in.
for (int i = 0; i < attends.size(); i++) {
Section s = (Section) attends.elementAt(i);
pw.println(s.getFullSectionNo());
}
pw.close();
fos.close(); //? needed?
}
catch (IOException e) {
// Signal that an error has occurred.
return false;
}
// All is well!
return true;
}
public Enumeration getEnrolledSections() {
return attends.elements();
}
// This next method was added for use with the GUI.
public Vector getSectionsEnrolled() {
return attends;
}
// This next method was added for use with the GUI.
public int getCourseTotal() {
return attends.size();
}
// This next method was added for use with the GUI.
public boolean validatePassword(String pw) {
if (pw == null) return false;
if (pw.equals(password)) return true;
else return false;
}
}