Proper way to Module Code for Problem

Question

Hi I am looking solution for this problem If any one can help me out .....
At ACME a "job" is a group of print items.
JOB For example, a job can be a run of business cards, envelopes, and letterhead together.
Some items qualify as being sales tax free, whereas, by default, others
are not. Sales tax is 7%.
ACME also applies a margin, which is the percentage above printing cost that is charged to the customer.
For example, an item that costs $100 to print that has a margin of 11% will cost:
item: $100 -> $7 sales tax = $107
job: $100 -> $11 margin
total: $100 + $7 + $11 = $118
The base margin is 11% for all jobs this problem. Some jobs have an "extra margin" of 5%. These jobs that are flagged as extra margin have an additional 5% margin (16% total) applied.
The final cost is rounded to the nearest even cent. Individual items are rounded to the nearest cent.
Write a program in Java that calculates the total charge to a customer for a job. The program should accept the inputs below and output the total bill for the customer.
Include this problem statement with your solution.
Job 1:
extra-margin
envelopes 520.00
letterhead 1983.37 exempt
should output:
envelopes: $556.40
letterhead: $1983.37
total: $2940.30
Job 2:
t-shirts 294.04
output:
t-shirts: $314.62
total: $346.96
Job 3:
extra-margin
frisbees 19385.38 exempt
yo-yos 1829 exempt
output:
frisbees: $19385.38
yo-yos: $1829.00
total: $24608.68
Thanks

Answer 1

I want to make best use of OOPS concepts to modularize this problem, like using interface, abstract class, etc. What to keep in mind (steps) before modularizing such a problem. If some one can focus some light on it , that would be of great use.
I had solution as under, But what else could be best way.
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
public class Job {
     private List itemList; //Job contains a list of Item objects
     //Job object can contain any number of Item objects, as given by user at runtime
     private boolean extraMarginApplied;
     private double totalCostforJob;
     //Following three variables will be provided by user
     //For each input, construct one item object and add it to the Job-ItemList
     private String itemName;
     private double itemCost;
     private boolean itemTaxExempted;
     private static final double SALESTAX = 0.07; //Sales tax applied
     private static final double MARGIN = 0.11;
     private static final double EXTRAMARGIN = 0.05;
     public Job() {
          itemList = new ArrayList();
     public String getItemName() {
          return itemName;
     public void setItemName(String itemName) {
          this.itemName = itemName;
     public double getItemCost() {
          return itemCost;
     public void setItemCost(double itemCost) {
          this.itemCost = itemCost;
     public boolean isItemTaxExempted() {
          return itemTaxExempted;
     public void setItemTaxExempted(boolean itemTaxExempted) {
          this.itemTaxExempted = itemTaxExempted;
     public List getItemList() {
          return itemList;
     public void setItemList(List itemList) {
          this.itemList = itemList;
     public boolean isExtraMarginApplied() {
          return extraMarginApplied;
     public void setExtraMarginApplied(boolean extraMargin) {
          this.extraMarginApplied = extraMargin;
     public double isTotalCostforJob() {
          return totalCostforJob;
     public void setTotalCostforJob(double totalCostforJob) {
          this.totalCostforJob = totalCostforJob;
     public Item getItemFromUser(InputStreamReader isr, BufferedReader br)
               throws IOException {
          System.out.println("Enter Item Name: ");
          setItemName(br.readLine());
          System.out.println("Enter Item Cost: ");
          setItemCost(Double.parseDouble(br.readLine()));
          System.out.println("Item Tax Exempted(Y/N)?: ");
          String input = br.readLine();
          if (input.equals("Y") || input.equals("y")) {
               setItemTaxExempted(true);
          } else {
               setItemTaxExempted(false);
          //Now construct an Item object and return it
          return new Item(itemName, itemCost, itemTaxExempted);
     public static String getSystemExit() throws IOException {
          System.out.println("\nDo you want to add more items(Y/N)?: ");
          InputStreamReader isr = new InputStreamReader(System.in);
          BufferedReader br = new BufferedReader(isr);
          return br.readLine();
     public void addItemToJob(InputStreamReader isr, BufferedReader br)
               throws IOException {
          itemList.add(getItemFromUser(isr, br));
     public static void main(String agr[]) throws IOException {
          String proceed;
          InputStreamReader isr = new InputStreamReader(System.in);
          BufferedReader br = new BufferedReader(isr);
          Job job = new Job();
          job.getExtraMargin(isr, br);
          do {
               job.addItemToJob(isr, br);
               proceed = getSystemExit();
          } while (proceed.equals("Y") || proceed.equals("y"));
          job.calculateAndPrintTotalCostforJob();
          br.close();
          isr.close();
     private void getExtraMargin(InputStreamReader isr, BufferedReader br)
               throws IOException {
          System.out
                    .println("Is extra margin to be charged for this Job?(Y/N)?: ");
          String input = br.readLine();
          if (input.equals("Y") || input.equals("y")) {
               setExtraMarginApplied(true);
          } else {
               setExtraMarginApplied(false);
     private void calculateAndPrintTotalCostforJob() {
          Iterator itr = itemList.iterator();
          Item item;
          double totalCost = 0;
          double itemCostWithSalesTax;
          while (itr.hasNext()) {
               item = (Item) itr.next();
               if (item.isTaxExempted()) {
                    itemCostWithSalesTax = item.getCost(); //No sales tax applied, so cost is same
               } else {
                    itemCostWithSalesTax = item.getCost() * (1 + SALESTAX); //Add sales tax
               if (isExtraMarginApplied()) {
                    totalCost = totalCost + itemCostWithSalesTax + item.getCost()
                              * (MARGIN + EXTRAMARGIN);
               } else {
                    totalCost = totalCost + itemCostWithSalesTax + item.getCost()
                              * MARGIN;
               System.out.println(item.getItemName() + ":  "
                         + itemCostWithSalesTax);
          setTotalCostforJob(totalCost);
          System.out.println("Total: " + totalCostforJob);
}=================================================================================
public class Item {
    private String itemName;
    private double cost;
    private boolean taxExempted=false;
    public Item(String itemName, double cost, boolean taxExp) {
        this.itemName = itemName;
        this.cost = cost;
        this.taxExempted = taxExp;
    public String getItemName() {
        return itemName;
    public void setItemName(String itemName) {
        this.itemName = itemName;
    public double getCost() {
        return cost;
    public void setCost(int cost) {
        this.cost = cost;
    public boolean isTaxExempted() {
        return taxExempted;
    public void setTaxExempted(boolean b) {
        this.taxExempted = b;
}Thank you for your help and guideline.