Obsługa koszyka - bezpośrednio za pomocą HttpSession

PC30-SklepSpring/src/main/java/sklep/basket/Basket.java

+package sklep.basket;
+
+import java.math.BigDecimal;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+import sklep.model.Product;
+
+public class Basket {
+	private final Map<Integer, ProductInBasket> elementy = new HashMap<>();
+	
+	public synchronized void addProduct(Product product, int quantity) {
+		if(elementy.containsKey(product.getProductId())) {
+			// jeśli w słowniku jest już taki element, to tylko zwiększamy ilość
+			elementy.get(product.getProductId()).increaseQuantity(quantity);
+		} else {
+			// jeśli jeszcze nie ma, to tworzymy
+			elementy.put(product.getProductId(),
+					new ProductInBasket(product.getProductId(), product.getProductName(), product.getPrice(), quantity));
+		}
+	}
+
+	public synchronized void addProduct(Product product) {
+		// "domyślną ilością, o którą zwiększamy, jest 1"
+		addProduct(product, 1);
+	}
+
+	
+	public synchronized Collection<ProductInBasket> getElements() {
+		return Collections.unmodifiableCollection(elementy.values());
+	}
+
+	public synchronized BigDecimal getTotalValue() {
+		return getElements().stream()
+				.map(ProductInBasket::getValue)
+				.reduce(BigDecimal.ZERO, BigDecimal::add);
+	}
+	
+	@Override
+	public synchronized String toString() {
+		return "Koszyk o rozmiarze " + getElements().size()
+				+ " i wartości " + getTotalValue();
+	}
+	
+}

PC30-SklepSpring/src/main/java/sklep/basket/ProductInBasket.java

+package sklep.basket;
+
+import java.math.BigDecimal;
+import java.util.Objects;
+
+public class ProductInBasket {
+    private int productId;
+    private String productName;
+    private BigDecimal price;
+    private int quantity;
+    
+	public ProductInBasket(int productId, String productName, BigDecimal price, int quantity) {
+		this.productId = productId;
+		this.productName = productName;
+		this.price = price;
+		this.quantity = quantity;
+	}
+
+	public BigDecimal getPrice() {
+		return price;
+	}
+
+	public void setPrice(BigDecimal price) {
+		this.price = price;
+	}
+
+	public int getQuantity() {
+		return quantity;
+	}
+
+	public void setQuantity(int quantity) {
+		this.quantity = quantity;
+	}
+
+	public int getProductId() {
+		return productId;
+	}
+
+	public String getProductName() {
+		return productName;
+	}
+
+	@Override
+	public String toString() {
+		return "ElementKoszyka [productId=" + productId + ", productName=" + productName + ", price=" + price
+				+ ", quantity=" + quantity + "]";
+	}
+	
+	@Override
+	public int hashCode() {
+		return Objects.hash(price, productId, productName, quantity);
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj)
+			return true;
+		if (obj == null)
+			return false;
+		if (getClass() != obj.getClass())
+			return false;
+		ProductInBasket other = (ProductInBasket) obj;
+		return Objects.equals(price, other.price) && productId == other.productId
+				&& Objects.equals(productName, other.productName) && quantity == other.quantity;
+	}
+
+	public BigDecimal getValue() {
+		return price.multiply(BigDecimal.valueOf(quantity));
+	}
+
+	public void increaseQuantity(int change) {
+		quantity += change;
+	}
+    
+}

PC30-SklepSpring/src/main/java/sklep/controller/ProductController.java

@@ -4,6 +4,7 @@ import java.math.BigDecimal;
 import java.util.List;
 import java.util.Optional;
 
+import javax.servlet.http.HttpSession;
 import javax.validation.Valid;
 
 import org.springframework.beans.factory.annotation.Autowired;
@@ -16,6 +17,7 @@ import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.ResponseBody;
 
+import sklep.basket.Basket;
 import sklep.model.Product;
 import sklep.photo.PhotoUtil;
 import sklep.repository.ProductRepository;
@@ -131,4 +133,21 @@ public class ProductController {
 		return photoUtil.readBytes(productId);
 	}
 
+	@GetMapping("/{id}/add-to-basket")
+	public String addToBasket(
+			@PathVariable("id") int productId,
+			HttpSession sesja) {
+		Basket basket = (Basket) sesja.getAttribute("basket");
+		if(basket == null) {
+			basket = new Basket();
+			sesja.setAttribute("basket", basket);
+		}
+		Optional<Product> product = productRepository.findById(productId);
+		if(product.isPresent()) {
+			basket.addProduct(product.get());
+		}
+		
+		return "redirect:/products";
+	}
+	
 }