Java tutorial
/* * Copyright 2010-2013, CloudBees Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.cloudbees.demo.beesshop.cart; import com.cloudbees.demo.beesshop.product.Product; import org.springframework.util.Assert; import javax.annotation.Nonnull; import java.io.Serializable; import java.math.BigDecimal; import java.text.NumberFormat; import java.util.Collection; import java.util.Locale; import java.util.SortedMap; import java.util.TreeMap; /** * @author <a href="mailto:cleclerc@cloudbees.com">Cyrille Le Clerc</a> */ public class ShoppingCart implements Serializable { /** * Number of added products by product */ private SortedMap<Product, ShoppingCartItem> items = new TreeMap<Product, ShoppingCartItem>(); public void addItem(Product product, int quantity) { ShoppingCartItem item = items.get(product); if (item == null) { items.put(product, new ShoppingCartItem(product, quantity)); } else { item.incrementQuantity(quantity); } } @Nonnull public Collection<ShoppingCartItem> getItems() { return items.values(); } public int getPriceInCents() { int totalPriceInCents = 0; for (ShoppingCartItem item : getItems()) { totalPriceInCents += item.getTotalPriceInCents(); } return totalPriceInCents; } /** * Price in dollars */ public String getPrettyPrice() { BigDecimal priceInDollars = new BigDecimal(getPriceInCents()).movePointLeft(2); return NumberFormat.getCurrencyInstance(Locale.US).format(priceInDollars); } public int getItemsCount() { int itemsCount = 0; for (ShoppingCartItem item : getItems()) { itemsCount += item.getQuantity(); } return itemsCount; } public static class ShoppingCartItem implements Comparable<ShoppingCartItem>, Serializable { @Nonnull private final Product product; private int quantity; public ShoppingCartItem(@Nonnull Product product, int quantity) { Assert.notNull(product, "given Product can NOT be null"); this.product = product; this.quantity = quantity; } public int getTotalPriceInCents() { return quantity * product.getPriceInCents(); } @Override public int compareTo(ShoppingCartItem o) { return this.product.compareTo(o.product); } public Product getProduct() { return product; } /** * @param quantity quantity to add for the item */ public void incrementQuantity(int quantity) { this.quantity += quantity; } public int getQuantity() { return quantity; } public void setQuantity(int quantity) { this.quantity = quantity; } @Override public boolean equals(Object o) { if (this == o) return true; if (!(o instanceof ShoppingCartItem)) return false; ShoppingCartItem that = (ShoppingCartItem) o; if (!product.equals(that.product)) return false; return true; } @Override public int hashCode() { return product.hashCode(); } } }