JAVA Programming help

This assignment is built using the code from Assignment 5.

In this assignment create a separate serialized file using ObjectOutputStream for each student.

File should contain student's score and statistics for entire class.

Using debug mode (with Debug flag) print the contents of the serialized file.

Create and implement an interface to:

Print student statistics.

Print scores for a given student id.

implement the Debug flag globally

Use an abstract class to implement all the methods declared in an interface.

Tips: --

package model;

public class Student implements Serializable {

}

package model;

public class Statistics implements Serializable{

}

package model;

public class StudentReport implements Serializable{

//we will serialize instances of Student Report.

private Student x; //for one student

private Statistics y; //for entire class.

//no default constructor as it will not make sense.

StudentReport(Student x, Statistics y)

{

this.x = x;

this.y = y;

}

//getter and setters

//print()

}

Student and Statistics are free of any static variables or methods - cannot be serialized.

//main

//stu is from student array - read from text file.

//stat object is from Statistics class.

public class Driver {

//run lab5 so data in student [] is loaded and statistics are computed.

//How to write one StudentReport to disk using serialization?

//StudentReport a1 = new StudentReport(stu, stat);

//FileIO f = new FileIO();

//f.writetodisk(a1);

//How to write n objects of StudentReport to disk using serialization?

//Assumption - u already have an array of students from lab5 from readdata()

//Build an array of StudentReport

StudentReport arr[] = new StudentReport[40];

//stu[] array is populated using lab5 read method (that reads from the file).

//building studentreport array

for(int i=0;i<40;i++)

{

if(stu[i]!=null) //avoiding NPE.

arr[i] = new StudentReport(stu[i], stat);

}

for(int i=0;i<40;i++)

{

if(arr[i]!=null)

{

StudentReport temp = arr[i];

Student temp2 = temp.getStudent();

int sid = temp2.getid();

String fname = sid + ".ser"; //this may not work???

f.writetodisk(arr[i],fname);

//f.writetodisk(arr[i],(arr[i].getStudent().getid().toString())+".ser"));

}

}

}

import java.io.*;

package util;

public class FileIO { //or Util or whatever name of class you are using in util package.

public void writetodisk(StudentReport a1, String fname)

{

try {

FileOutputStream p = new FileOutputStream(fname);

ObjectOutputStream p1 = new ObjectOutputStream(p);

p1.writeObject(a1);

}

catch(Exception e)

{

//exception message

}

}

public StudentReport readfromdisk(String fname)

{

StudentReport a= null;

try {

FileInputStream p = new FileInputStream(fname);

ObjectInputStream p1 = new ObjectInputStream(p);

a = (StudentReport )p1.readObject();

}

catch(Exception e)

{

//exception message

}

return a;

}

}

Using debug mode (with Debug flag) print the contents of the serialized file.

Create and implement an interface to:

..Print student statistics.

..Print scores for a given student id.

..implement the Debug flag globally

//....Use an abstract class to implement all the methods declared in an interface.

Interface -

face - input/output

inter - communication

Adding a face to software for communication.

public interface Faceable {

public final boolean DEBUG=false; //global variables.

public void smile();

}

public class Human implements Faceable {

//enforces a contract to Human to implement smile() method.

//if Human does not implement methods in Faceable interface - then compiler error.

public void smile() {

System.out.println("..smile from human");

}

}

public class Ape implements Faceable {

public void smile() {

System.out.println("..smile from ape");

}

}

Human a1 = new Human();

a1.smile();

Ape a2 = new Ape();

a2.smile();

Faceable a3;

a3 = a1;

a3.smile();

a3 = a2;

a3.smile();

Making a face for software -

Using debug mode (with Debug flag) print the contents of the serialized file.

Create and implement an interface to:

..Print student statistics.

..Print scores for a given student id.

..implement the Debug flag globally

package adapter;

public interface Printable{

public final boolean DEBUG = false;

public void getStats(); //prints students statistics.

public void printstudentscores(int id);

}

import model.*;

import util.*;

package adapter;

public class Print implements Printable {

//use debug flag for printing. if debug = true then print other no printing.

public void getStats() {

//print stats from any object - read one object from disk and print stats.

}

public void printstudentscores(int id) {

//use the serialized life so your life is easy.

//pl. don't use search in studentreport array. long way. no good.

}

}

//how to use an interface in main()

Printable p1 = new Print();

p1.getStats();

p1.printstudentscores(1234);

p1.printstudentscores(9111); //invalid student id shld print a friendly message - no such student.

____________________________________________________________________________________________________

ASSIGNMENT 5 CODE

import fileIO.Util;

import model.Statistics;

import model.Student;

public class Driver

{

public static void main(String[] args)

{

Student arrStudent[] = new Student[40];

int studentCount=0;

arrStudent = Util.readFile("C:\\Users\\JamesJr\\eclipse-workspace\\Assignment 5\\src\\Scores.txt", arrStudent);

// find number of lines from file. which will show number of students in array.

studentCount= Util.studentCount;

Statistics s = new Statistics();

System.out.printf("\t\t\t\tStud\tQu1\tQu2\tQu3\tQu4\tQu5 ");

// print student data fetched from file

for(int i = 0; i

{

arrStudent[i].printData();

}

// print statistics of students

s.printStatistics(arrStudent,studentCount);

}

}

------------------------------------------------------------------------------------------------------

package fileIO;

import java.io.BufferedReader;

import java.io.FileReader;

import java.io.IOException;

import java.util.StringTokenizer;

import model.Student;

public class Util

{

public static int studentCount;

public static Student[] readFile(String filename, Student[] stu)

{

int i = 0;

try

{

FileReader file = new FileReader(filename);

BufferedReader buff = new BufferedReader(file);

boolean eof = false;

boolean firstLineSkipped = false;

while (!eof)

{

String line = buff.readLine();

if (line == null)

{

eof = true;

}

else

{

if (!firstLineSkipped)

{

firstLineSkipped = true;

continue;

}

stu[i] = new Student();

StringTokenizer st = new StringTokenizer(line);

while (st.hasMoreTokens())

{

stu[i].setSID(Integer.parseInt(st.nextToken()));

int[] arr = new int[5];

for (int j = 0; j < 5; j++)

{

arr[j] = Integer.parseInt(st.nextToken());

}

stu[i].setScores(arr);

}

}

i++;

}

buff.close();

}

catch (IOException e)

{

System.out.printf("Error -- " + e.toString());

}

studentCount = i-1;

return stu;

}

}

-------------------------------------------------------------------------------------------------------

package model;

public class Statistics implements Serializable

{

private int[] lowscores= new int[5];

private int[] highscores= new int[5];

private float[] avgscores= new float[5];

void findlow(Student[] a, int c)

{

// finds low score.

int i=0;

for(i=0;i<5; i++)

{

int[] temp= a[0].getScores();

int min = temp[i];

for(int j=0; j< c; j++)

{

int[] s= a[j].getScores();

if(min > s[i])

{

min = s[i];

}

}

lowscores[i]= min;

}

}

//find high score

void findhigh(Student[] a, int c)

{

int i=0;

for(i=0;i<5; i++)

{

int[] temp= a[0].getScores();

int max = temp[i];

for(int j=0; j< c; j++)

{

int[] s= a[j].getScores();

if(max < s[i])

{

max = s[i];

}

}

highscores[i]= max;

}

}

//find average score.

void findavg(Student[] a, int c)

{

int i=0;

for(i=0;i<5; i++)

{

int sum =0;

for(int j=0; j

{

int[] s= a[j].getScores();

sum= sum + s[i];

}

avgscores[i]= sum/c;

}

}

//print statistics for all students and all quizes

public void printStatistics(Student[] a, int c)

{

findlow(a,c);

findhigh(a,c);

findavg(a,c);

System.out.printf("\t\t\tLowest score :\t" + lowscores[0] + "\t" + lowscores[1] + "\t" + lowscores[2] + "\t" + lowscores[3] + "\t" + lowscores[4] + " ");

System.out.printf("\t\t\tHigh score :\t" + highscores[0] + "\t" + highscores[1] + "\t" + highscores[2] + "\t" + highscores[3] + "\t" + highscores[4] + " ");

System.out.printf("\t\t\tAverage score :\t" + avgscores[0] + "\t" + avgscores[1] + "\t" + avgscores[2] + "\t" + avgscores[3] + "\t" + avgscores[4] + " ");

}

}

------------------------------------------------------------------------------------------------------

package model;

public class Student implements Serializable

{

private int SID;

private int scores[] = new int[5];

//getter and setter functions

public int getSID()

{

return this.SID;

}

public void setSID(int id)

{

this.SID= id;

}

public int[] getScores()

{

return this.scores;

}

public void setScores(int[] s)

{

this.scores= s;

}

//print all data of a student

public void printData()

{

System.out.printf("\t\t\t\t"+ SID +"\t"+ scores[0] +"\t"+ scores[1] +"\t"+ scores[2] + "\t"+ scores[3] +"\t"+ scores[4] +" ");

}

}

------------------------------------------------------------------------------------------------------

Assignment 5 prompt

Object Relationship and File IO

Write a program to perform statistical analysis of scores for a class of students.The class may have up to 40 students.

There are five quizzes during the term. Each student is identified by a four-digit student ID number.

The program is to print the student scores and calculate and print the statistics for each quiz. The output is in

the same order as the input; no sorting is needed. The input is to be read from a text file. The output from the

program should be similar to the following:

Here is some sample data (not to be used) for calculations:

Stud Q1 Q2 Q3 Q4 Q5

1234 78 83 87 91 86

2134 67 77 84 82 79

1852 77 89 93 87 71

High Score 78 89 93 91 86

Low Score 67 77 84 82 71

Average 73.4 83.0 88.2 86.6 78.6

The program should print the lowest and highest scores for each quiz.

Plan of Attack

Learning Objectives

You will apply the following topics in this assignment:

File Input operations.

Working and populating an array of objects.

Wrapper Classes.

Object Oriented Design and Programming.

Understanding Requirements

Here is a copy of actual data to be used for input.

Stud Qu1 Qu2 Qu3 Qu4 Qu5

1234 052 007 100 078 034

2134 090 036 090 077 030

3124 100 045 020 090 070

4532 011 017 081 032 077

5678 020 012 045 078 034

6134 034 080 055 078 045

7874 060 100 056 078 078

8026 070 010 066 078 056

9893 034 009 077 078 020

1947 045 040 088 078 055

2877 055 050 099 078 080

3189 022 070 100 078 077

4602 089 050 091 078 060

5405 011 011 000 078 010

6999 000 098 089 078 020

Essentially, you have to do the following:

Read Student data from a text file.

Compute High, Low and Average for each quiz.

Print the Student data and display statistical information like High/Low/Average..

Design

This program can be written in one class. But dividing the code into simple and modular classes based on functionality, is

at the heart of Object Oriented Design.

You must learn the concepts covered in the class and find a way to apply.

Please make sure that you put each class in its own .java file.

package lab2;

class Student {

private int SID;

private int scores[] = new int[5];

//write public get and set methods for

//SID and scores

//add methods to print values of instance variables.

}

/************************************************************************************/

package lab2;

class Statistics

{

int [] lowscores = new int [5];

int [] highscores = new int [5];

float [] avgscores = new float [5];

void findlow(Student [] a) {

/* This method will find the lowest score and store it in an array names lowscores. */

}

void findhigh(Student [] a) {

/* This method will find the highest score and store it in an array names highscores. */

}

void findavg(Student [] a) {

/* This method will find avg score for each quiz and store it in an array names avgscores. */

}

//add methods to print values of instance variables.

}

************************************************************************************/

package lab2;

class Util {

Student [] readFile(String filename, Student [] stu) {

//Reads the file and builds student array.

//Open the file using FileReader Object.

//In a loop read a line using readLine method.

//Tokenize each line using StringTokenizer Object

//Each token is converted from String to Integer using parseInt method

//Value is then saved in the right property of Student Object.

}

}

************************************************************************************/

//Putting it together in driver class:

public static void main(String [] args) {

Student lab2 [] = new Student[40];

//Populate the student array

lab2 = Util.readFile("filename.txt", lab2);

Statistics statlab2 = new Statistics();

statlab2.findlow(lab2);

//add calls to findhigh and find average

//Print the data and statistics

}

Topics to Learn

Working with Text Files

//ReadSource.java -- shows how to work with readLine and FileReader

public class ReadSource {

public static void main(String[] arguments) {

try {

FileReader file = new FileReader("ReadSource.java");

BufferedReader buff = new BufferedReader(file);

boolean eof = false;

while (!eof) {

String line = buff.readLine();

if (line == null)

eof = true;

else

System.out.println(line);

}

buff.close();

} catch (IOException e) {

System.out.println("Error -- " + e.toString());

}

}

}

//How do you tokenize a String? You can use other ways of doing this, if you like.

StringTokenizer st = new StringTokenizer("this is a test");

while (st.hasMoreTokens()) {

System.out.println(st.nextToken());

}

//How to convert a String to an Integer

int x = Integer.parseInt(String) ;