Obsługa koszyka

PC24-SklepWeb/src/main/java/sklep/basket/AddToBasket.java

+package sklep.basket;
+
+import java.io.IOException;
+
+import jakarta.servlet.ServletException;
+import jakarta.servlet.annotation.WebServlet;
+import jakarta.servlet.http.HttpServlet;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import jakarta.servlet.http.HttpSession;
+import sklep.db.DBConnection;
+import sklep.db.ProductDAO;
+import sklep.model.Product;
+
+@WebServlet("/add_to_basket")
+public class AddToBasket extends HttpServlet {
+
+    @Override
+    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        try {
+            int productId = Integer.parseInt(request.getParameter("productId"));
+            try(DBConnection db = DBConnection.open()) {
+                ProductDAO productDAO = db.productDAO();
+                Product product = productDAO.findById(productId);
+                
+                HttpSession sesja = request.getSession();
+                Basket basket = (Basket)sesja.getAttribute("basket");
+                // Zakładamy, że obiekt basket został dodany do sesji przez BasketListener
+                basket.addProduct(product);
+            }
+        } catch(Exception e) {
+            // ignorujemy błędy
+        }
+        // Przekierowanie - każemy przeglądarce wejść pod ten adres.
+        response.sendRedirect("products8.jsp");
+    }
+
+}

PC24-SklepWeb/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 void removeProduct(int productId) {
+        ProductInBasket p = elementy.get(productId);
+        if(p != null) {
+            if(p.getQuantity() > 1) {
+                p.increaseQuantity(-1);
+            } else {
+                elementy.remove(productId);
+            }
+        }
+    }
+    
+    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();
+    }
+    
+}

PC24-SklepWeb/src/main/java/sklep/basket/BasketListener.java

+package sklep.basket;
+
+import jakarta.servlet.ServletContextEvent;
+import jakarta.servlet.ServletContextListener;
+import jakarta.servlet.annotation.WebListener;
+import jakarta.servlet.http.HttpSession;
+import jakarta.servlet.http.HttpSessionEvent;
+import jakarta.servlet.http.HttpSessionListener;
+
+@WebListener
+public class BasketListener implements HttpSessionListener, ServletContextListener {
+
+    public void sessionCreated(HttpSessionEvent se) {
+        HttpSession sesja = se.getSession();
+        sesja.setMaxInactiveInterval(30); // pół minuty i sesja wygasa
+        System.out.println("sessionCreated " + sesja.getId());
+        Basket basket = new Basket();
+        sesja.setAttribute("basket", basket);
+    }
+
+    public void sessionDestroyed(HttpSessionEvent se)  {
+        HttpSession sesja = se.getSession();
+        System.out.println("sessionDestroyed "  + sesja.getId());
+    }
+
+    public void contextInitialized(ServletContextEvent sce) {
+        System.out.println("contextInitialized");
+    }
+
+    public void contextDestroyed(ServletContextEvent sce) {
+        System.out.println("contextDestroyed");
+    }
+
+}

PC24-SklepWeb/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;
+    }
+
+}

PC24-SklepWeb/src/main/java/sklep/basket/RemoveFromBasket.java

+package sklep.basket;
+
+import java.io.IOException;
+
+import jakarta.servlet.ServletException;
+import jakarta.servlet.annotation.WebServlet;
+import jakarta.servlet.http.HttpServlet;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import jakarta.servlet.http.HttpSession;
+
+@WebServlet("/remove_from_basket")
+public class RemoveFromBasket extends HttpServlet {
+
+    @Override
+    protected void doGet(HttpServletRequest request, HttpServletResponse response)
+            throws ServletException, IOException {
+        try {
+            int productId = Integer.parseInt(request.getParameter("productId"));
+            HttpSession sesja = request.getSession();
+            Basket basket = (Basket) sesja.getAttribute("basket");
+            basket.removeProduct(productId);
+        } catch (Exception e) {
+            // ignorujemy błędy
+        }
+        // Przekierowanie - każemy przeglądarce wejść pod ten adres.
+        response.sendRedirect("products8.jsp");
+    }
+
+}

PC24-SklepWeb/src/main/webapp/products8.jsp

+<%@page contentType="text/html;charset=UTF-8" language="java" %>
+<%@taglib prefix="c" uri="jakarta.tags.core"%>
+<!DOCTYPE html>
+<html>
+<head>
+    <meta charset="UTF-8">
+    <title>Lista produktów 8</title>
+    <link rel="stylesheet" type="text/css" href="styl.css">
+</head>
+<body>
+<h1>Lista produktów - wersja 8</h1>
+
+<div class="koszyk">
+    <h4>Koszyk</h4>
+    <ul>
+        <%-- Zauważmy, że dla obiektu koszyk nie wykonujemy już useBean.
+             Po prostu zakładamy, że jest obecny (w sesji). Gdyby go nie było, to pętla się nie wykona. --%>
+        <c:forEach var="elm" items="${basket.elements}">
+            <li>${elm.productName} (${elm.quantity}) za <b>${elm.value}</b> <a href="remove_from_basket?productId=${elm.productId}">(–)</a></li>
+        </c:forEach>
+    </ul>
+    <p class="total">Do zapłaty: ${basket.totalValue}</p>
+</div>
+
+<form id="wyszukiwarka" method="get">
+    <h2>Filtr cen</h2>
+    <table class="formularz">
+        <tr><td><label for="min_price">Cena minimalna:</label></td>
+            <td><input id="min_price" name="min_price" type="number" value="${param.min_price}"></td></tr>
+        <tr><td><label for="max_price">Cena maksymalna:</label></td>
+            <td><input id="max_price" name="max_price" type="number" value="${param.max_price}"></td></tr>
+        <tr><td><button>Filtruj</button></td></tr>
+    </table>
+</form>
+
+<jsp:useBean id="bean" class="sklep.web.ProductBean"/>
+<jsp:setProperty name="bean" property="minPrice" param="min_price"/>
+<jsp:setProperty name="bean" property="maxPrice" param="max_price"/>
+
+<c:forEach var="product" items="${bean.filteredProducts}">
+    <div class="product">
+        <h3>${product.productName}</h3>
+        <div class="price">Cena: ${product.price}</div>
+        <div class="price">VAT ${product.vat * 100}%</div>
+        <c:if test="${not empty(product.description)}">
+            <p class="description">${product.description}</p>
+        </c:if>
+        <div class="action"><a href="add_to_basket?productId=${product.productId}">dodaj do koszyka</a></div>
+        <div class="action"><a href="edit?productId=${product.productId}">edytuj</a></div>
+    </div>
+</c:forEach>
+<div class="action"><a href="edit">Dodaj nowy produkt</a></div>
+</body>
+</html>