Product Analysis using java streams

Beginner/ProductAnalysis.java

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+import java.util.*;
+import java.util.stream.Collectors;
+/**
+ * Program Title: Count how many products are in each category
+ * Author: [hirushi1999]
+ * Date: 2025-10-14
+ * Demonstrates how to use Java Streams to perform data analysis on a list of products.
+ * Time Complexity: O(n) (Linear time)
+ * Space Complexity: O(k) (Where k is the number of distinct categories)
+ * Scenario:
+ * - A store sells products in various categories (Fruits, Vegetables, Dairy, Meat).
+ * - Each product has a price, quantity sold, and availability status.
+ * Task:
+ * 1. Count how many products are in each category.
+ */
+class Product {
+    private String name;
+    private String category;
+    private double price;
+    private int quantitySold;
+    private boolean inStock;
+
+    public Product(String name, String category, double price, int quantitySold, boolean inStock) {
+        this.name = name;
+        this.category = category;
+        this.price = price;
+        this.quantitySold = quantitySold;
+        this.inStock = inStock;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getCategory() {
+        return category;
+    }
+
+    public void setCategory(String category) {
+        this.category = category;
+    }
+
+    public double getPrice() {
+        return price;
+    }
+
+    public void setPrice(double price) {
+        this.price = price;
+    }
+
+    public int getQuantitySold() {
+        return quantitySold;
+    }
+
+    public void setQuantitySold(int quantitySold) {
+        this.quantitySold = quantitySold;
+    }
+
+    public boolean isInStock() {
+        return inStock;
+    }
+
+    public void setInStock(boolean inStock) {
+        this.inStock = inStock;
+    }
+}
+
+public class ProductAnalysis {
+    public static void main(String[] args) {
+        List<Product> productList = Arrays.asList(
+                new Product("Apple", "Fruits", 120.0, 50, true),
+                new Product("Banana", "Fruits", 80.0, 80, true),
+                new Product("Carrot", "Vegetables", 60.0, 70, true),
+                new Product("Broccoli", "Vegetables", 90.0, 40, false),
+                new Product("Milk", "Dairy", 150.0, 30, true),
+                new Product("Cheese", "Dairy", 500.0, 15, true),
+                new Product("Yogurt", "Dairy", 200.0, 25, false),
+                new Product("Chicken", "Meat", 800.0, 20, true),
+                new Product("Beef", "Meat", 1200.0, 10, true),
+                new Product("Fish", "Meat", 950.0, 18, false));
+
+        System.out.println("1. Count how many products are in each category");
+        // Group products by category and count them
+        Map<String, Long> map = productList.stream().collect(Collectors.groupingBy(Product::getCategory,Collectors.counting()));
+        // Display results
+        map.forEach((cate, count) -> System.out.println(cate + ": " + count));
+    }
+}