HW-06-exceptions-and-file-handling #1
+14
-10
@@ -14,16 +14,20 @@ public class Main {
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throw new IOException("products.csv not found");
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}
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Scanner scanner = new Scanner(input);
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// TODO:
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// - Read each line from products.csv
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// - For each line, parse productId, name, and price
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// - The format of the file is like this:
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// [productId],[name],[price]
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// - Store Product objects in the productCatalog ArrayList
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// NOTE
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// - The data in products.csv is guaranteed to be valid.
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try{
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while(scanner.hasNextLine()){
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String line = scanner.nextLine();
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String [] parts = line.split(",",3);
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int productId = Integer.parseInt(parts[0]);
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String name = parts[1];
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double price = Double.parseDouble(parts[2]);
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Product product = new Product(productId , name , price);
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productCatalog.add(product);
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}
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}finally {
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scanner.close();
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input.close();
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}
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}
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public static void main(String[] args)
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@@ -1,4 +1,9 @@
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import java.io.File;
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import java.io.FileNotFoundException;
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import java.io.FileWriter;
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import java.io.IOException;
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import java.util.List;
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import java.util.Scanner;
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public class ReportGenerator {
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@@ -15,69 +20,105 @@ public class ReportGenerator {
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this.productList = productList;
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}
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public void processFile()
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{
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// TODO:
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// 1. Open the order details CSV file
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// 2. Read the file line by line
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// 3. Split each line using comma delimiter
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// (each line is guaranteed to contain exactly two commas)
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// 4. Each line contains exactly 3 values in the format:
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// [productId],[quantity],[discountPercent]
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// 5. Attempt to convert values:
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// - productId -> int
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// - quantity -> int
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// - discountPercent -> int
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// NOTE:
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// - quantity and discountPercent may contain invalid characters
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// (e.g., letters instead of numbers).
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// - If parsing any value fails (NumberFormatException),
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// the entire line must be considered invalid.
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// - Use try-catch blocks and exception handling to safely
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// handle parsing and validation errors without stopping
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// the processing of the remaining lines.
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// 6. Validate parsed values:
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// - productId must be greater than 0
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// - quantity must be greater than 0
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// - discountPercent must be between 0 and 99 inclusive
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// 7. Look for a Product in productList that matches productId
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// 8. If no Product with that ID exists in the catalog,
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// the entire line is considered invalid
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// 9. If all values are valid and the product exists, calculate:
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// subtotal = quantity * product price
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// discountValue = subtotal * discountPercent / 100
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// finalCost = subtotal - discountValue
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// 10. Update report totals:
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// - totalQuantity += quantity
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// - totalFinalCost += finalCost
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// - totalDiscountValue += discountValue
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// 11. If any parsing error, validation failure, or missing product occurs:
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// - increment totalInvalidLines
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// - skip the line and continue processing the next line
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// 12. Close all file resources
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public void processFile(){
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File file = new File(ordersFilePath);
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try (Scanner scanner = new Scanner(file)){
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while (scanner.hasNextLine()){
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String line = scanner.nextLine();
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if (line.trim().isEmpty()){
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continue;
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}
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String [] parts = line.split(",",3);
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if(parts.length !=3){
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totalInvalidLines++;
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continue;
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}
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int productId = 0;
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int quantity = 0;
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int discountPercent = 0;
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boolean lineValid = true;
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try{
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productId = Integer.parseInt(parts[0].trim());
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}catch (NumberFormatException e){
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lineValid = false;
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}
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try{
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quantity = Integer.parseInt(parts[1].trim());
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}catch (NumberFormatException e){
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lineValid = false;
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}
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try{
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discountPercent = Integer.parseInt(parts[2].trim());
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}catch (NumberFormatException e){
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lineValid = false;
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}
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if (lineValid){
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if (productId <= 0 || quantity <=0 || discountPercent <0 ||discountPercent >99){
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lineValid = false;
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}
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}
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Product matchingProduct = null;
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if(lineValid){
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for(Product product : productList){
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if(product.getProductID() == productId){
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matchingProduct = product;
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break;
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}
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}
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if(matchingProduct == null){
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lineValid = false;
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}
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}
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if(lineValid){
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double subtotal = quantity * matchingProduct.getPrice();
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double discountValue = subtotal * discountPercent / 100.0;
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double finalCost = subtotal - discountValue;
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totalQuantity += quantity;
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totalFinalCost += finalCost;
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totalDiscountValue += discountValue;
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}else{
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totalInvalidLines ++;
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}
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}
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} catch (FileNotFoundException e) {
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System.out.println("Orders file not found: " + e.getMessage());
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}
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}
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public void saveReport()
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{
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// TODO:
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// 1. Build a formatted report string
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// 2. Include:
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// - total quantity
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// - total final cost
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// - total discount value
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// - total invalid lines
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// 3. Create/open output report file (name it report.txt)
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// 4. Write report string into file
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// 5. Handle file writing exceptions
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// 6. Close writer resources
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public void saveReport(){
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StringBuilder report = new StringBuilder();
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/* Example Structure
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========= SALES REPORT =========
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Total Quantity Sold: 42
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Total Final Cost: $1520.75
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Total Discount Value: $230.50
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Invalid Rows: 3
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================================
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*/
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report.append("========= SALES REPORT =========\n");
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report.append(String.format(java.util.Locale.US, "Total Quantity Sold: %d\n", totalQuantity));
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report.append(String.format(java.util.Locale.US, "Total Final Cost: $%.2f\n", totalFinalCost));
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report.append(String.format(java.util.Locale.US, "Total Discount Value: $%.2f\n", totalDiscountValue));
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report.append(String.format(java.util.Locale.US, "Invalid Rows: %d\n", totalInvalidLines));
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report.append("================================\n");
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FileWriter writer = null;
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try {
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writer = new FileWriter("report.txt");
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writer.write(report.toString());
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} catch (IOException e) {
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System.err.println("Error writing report file.");
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} finally {
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if (writer != null) {
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try {
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writer.close();
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} catch (IOException e) {
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System.err.println("Error closing report file.");
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}
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}
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}
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}
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}
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