相似物体数量

Question

import java.util.Date;

public class MyRestaurantTester {

public static void main(String[] args) {
    Date currentDate = new Date();
    Paraggelia order1 = new Paraggelia(currentDate,"11B");
    Product Beer = new Product("Amstel","111222",1.20f);
    Product Beef = new Product("Pork Beef","333444",8.50f);

    order1.add(Beer);
    order1.add(Beef);
    System.out.println(order1.getReceipt(30f));

}

}

import java.util.ArrayList;
import java.util.Date;

/*Notes to self:
 * -Work on Comments
 * -Javadocs maybe? 
 * -try to optimize the rough code.
 */

/*Order class*/
public class Paraggelia {

    private Date orderDate;
    private String tableNumber;
    private int customerCount;
    private ArrayList<Product> listOfItems;

    /*Constructor(s)*/

    Paraggelia(Date orderDate,String tableNumber){
        this.orderDate=orderDate;
        this.tableNumber=tableNumber;
        this.listOfItems = new ArrayList<Product>();
    }


    /*Add && Delete Products from the Order class*/

    public void add(Product p){
        if(p == null)
        {
            throw new IllegalArgumentException();
        }else{
        listOfItems.add(p);
        }
    }

    public void delete(Product p){
        if(p == null)
        {
            throw new IllegalArgumentException();
        }
        else
        {
            listOfItems.remove(p);
        }
    }

    /** Calculates and returns the total price
     * Usually called directly as a parameter of getReceipt function
     * */
    public static float getTotalPrice(){

        return 0;
    }

    /** Creates and returns the final Receipt! 
     * -Display must consist of:
     * Item$ - BarCode# - Item Amount#
     * Total Price#
     * Table Number#
     */
    public  String getReceipt(float totalPrice){
        StringBuilder receipt = new StringBuilder();
        for(int i =0; i<this.listOfItems.size();i++){
        receipt.append(listOfItems.get(i).getName());
        receipt.append("\n");
        }

        return new String(receipt);
    }


    /*Getters && Setters */
    public Date getOrderDate() {
        return orderDate;
    }
    public void setOrderDate(Date orderDate) {
        this.orderDate = orderDate;
    }
    public String getTableNumber() {
        return tableNumber;
    }
    public void setTableNumber(String tableNumber) {
        this.tableNumber = tableNumber;
    }
    public int getCustomerCount() {
        return customerCount;
    }
    public void setCustomerCount(int customerCount) {
        this.customerCount = customerCount;
    }

}

产品类别：

public class Product {

    private String Name;
    private String barCode;
    private float sellingPrice;

    /*Constructors: */
    Product(){}

    Product(String Name,String barCode,float sellingPrice){
        this.Name=Name;
        this.barCode=barCode;
        this.sellingPrice=sellingPrice;             
    }

    /*Getters & Setters*/
    public String getName() {
        return Name;
    }

    public void setName(String name) {
        Name = name;
    }

    public String getBarCode() {
        return barCode;
    }

    public void setBarCode(String barCode) {
        this.barCode = barCode;
    }

    public float getSellingPrice() {
        return sellingPrice;
    }

    public void setSellingPrice(float sellingPrice) {
        this.sellingPrice = sellingPrice;
    }

}

Answer 1

您可以使用Map（例如HashMap）代替ArrayList（List）

MyRestaurantTester

public class MyRestaurantTester {

    public static void main(String[] args) {
        Date currentDate = new Date();
        Paraggelia order1 = new Paraggelia(currentDate,"11B");
        Product Beer = new Product("Amstel","111222",1.20f);
        Product Beef = new Product("Pork Beef","333444",8.50f);

        order1.add(Beer, 1);
        order1.add(Beef, 5);
        System.out.println(order1.getReceipt(30f));

    }

}

肺结核

class Paraggelia {

    private Date orderDate;
    private String tableNumber;
    private int customerCount;
    private Map<Product, Integer> listOfItems;

    /*Constructor(s)*/

    Paraggelia(Date orderDate,String tableNumber){
        this.orderDate=orderDate;
        this.tableNumber=tableNumber;
        this.listOfItems = new HashMap<Product, Integer>();
    }


    /*Add && Delete Products from the Order class*/

    public void add(Product p, int quantity){
        if(p == null)
        {
            throw new IllegalArgumentException();
        }else{
            listOfItems.put(p, quantity);
        }
    }

    public void delete(Product p){
        if(p == null)
        {
            throw new IllegalArgumentException();
        }
        else
        {
            listOfItems.remove(p);
        }
    }

    /** Calculates and returns the total price
     * Usually called directly as a parameter of getReceipt function
     * */
    public static float getTotalPrice(){

        return 0;
    }

    /** Creates and returns the final Receipt!
     * -Display must consist of:
     * Item$ - BarCode# - Item Amount#
     * Total Price#
     * Table Number#
     */
    public  String getReceipt(float totalPrice){
        StringBuilder receipt = new StringBuilder();

        for(Map.Entry<Product,Integer> entry : this.listOfItems.entrySet()) {
            Product product = entry.getKey();
            Integer quantity = entry.getValue();

            receipt.append(product.getName() + " " + quantity);
            receipt.append("\n");
        }

        return new String(receipt);
    }


    /*Getters && Setters */
    public Date getOrderDate() {
        return orderDate;
    }
    public void setOrderDate(Date orderDate) {
        this.orderDate = orderDate;
    }
    public String getTableNumber() {
        return tableNumber;
    }
    public void setTableNumber(String tableNumber) {
        this.tableNumber = tableNumber;
    }
    public int getCustomerCount() {
        return customerCount;
    }
    public void setCustomerCount(int customerCount) {
        this.customerCount = customerCount;
    }

}

产出：