Question

到目前为止我所拥有的：

class abstract Product {

    public int daysTillExpiration;

    public int dateofManufacture ;

    public Product ( int daysTillExpiration, int dateofManufacture ) {
      this.daysTillExpiration = daysTillExpiration;
      this.dateofManufacture = dateofManufacture;
    }

    int getDaysTillExpiration(){
      return daysTillExpiration;
    }

    int getDateofManufacture() {
      return dateofManufacture;
    }
}

班级厨房：

import java.util.ArrayList;

public class Kitchen {

  ArrayList<Product> contents = new ArrayList<>();

  ArrayList<Product> getcontents ()
  {
    return contents;
  }
}

我创建了产品类（鸡蛋，葡萄酒和奶酪）并扩展了产品类。

我需要做什么;

我有一个Kitchen，Product中的每个Kitchen都有一个到期日，

这是在创建后初始化x天

 x =  for wine 3 years
      for cheese 10 days 
      for eggs 2 days

询问应该来自Kitchen - 厨房中的哪个产品首先到期？

Answer 1

假设您有一个类似于

的Product类

 public class Product
  {
    private Date purchaseDate = null;
    private int daysTillExpiry = 0;
    private Date expiryDate = null;
    private String productDescription = null;

    public Product(Date purchaseDate, int daysTillExpiry, String productDescription)
    {
      this.purchaseDate = purchaseDate;
      this.daysTillExpiry = daysTillExpiry;
      this.productDescription = productDescription;

      Calendar calendar = Calendar.getInstance();
      calendar.setTime(purchaseDate);
      calendar.add(Calendar.DAY_OF_YEAR, daysTillExpiry);
      expiryDate = calendar.getTime();
    }

    public Date getPurchaseDate()
    {
      return purchaseDate;
    }

    public int getDaysTillExpiry()
    {
      return daysTillExpiry;
    }

    public Date getExpiryDate()
    {
      return expiryDate;
    }

    public String getProductDescription()
    {
      return productDescription;
    }
  }

和像

这样的Kitchen类

  public class Kitchen
  {
    private List<Product> productList = new ArrayList<Product>();


    public List<Product> getProductList()
    {
      return productList;
    }
  }

然后它只是使用Comparator

我在下面创建了一个测试类，在Comparator方法

中实现了printList()

public class ProductsExpire
{
  private Kitchen kitchen = new Kitchen();


  public static void main(String[] args)
  {
    ProductsExpire productsExpire = new ProductsExpire();
    productsExpire.addProduct(new Date() ,1095,"wine");
    productsExpire.addProduct(new Date() ,10,"cheese");
    productsExpire.addProduct(new Date() ,3,"eggs");
    productsExpire.printList();
  }


  public void addProduct(Date purchaseDate, int daysTillExpiry, String productDescription)
  {
    kitchen.getProductList().add(new Product(purchaseDate, daysTillExpiry, productDescription));
  }

  public void printList()
  {
    Collections.sort(kitchen.getProductList(), new Comparator<Product>()
    {
      @Override
      public int compare(Product leftProduct, Product rightProduct)
      {
        return leftProduct.getExpiryDate().compareTo(rightProduct.getExpiryDate());
      }
    });

    for (Product product : kitchen.getProductList())
    {
      System.out.println(product.getProductDescription() + " " + product.getExpiryDate());
    }
  }
}

Answer 2

<强>代码：

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;

public class QuickTester {

    public static void main(String[] args) {

        Kitchen myKitchen = new Kitchen();

        myKitchen.addProduct(new Wine("Red Wine", 20150611));
        myKitchen.addProduct(new Cheese("White Cheese", 20150611));
        myKitchen.addProduct(new Wine("White Wine", 20150611));
        myKitchen.addProduct(new Egg("Big Egg", 20150611));

        Product p = myKitchen.getEarliestExpiringProduct();
        System.out.println("Name: " + p.getName() +
                ", Days Left: " + p.getDaysTillExpiration());
    }
}

abstract class Product {

    private String name;
    private int daysTillExpiration;
    private int dateOfManufacture;

    public Product(String name, int daysTillExpiration,
            int dateOfManufacture) {
        this.name = name;
        this.daysTillExpiration = daysTillExpiration;
        this.dateOfManufacture = dateOfManufacture;
    }

    public String getName() { return name; }
    public int getDaysTillExpiration() { return daysTillExpiration; }
    public int getDateofManufacture() { return dateOfManufacture; }
}

class Wine extends Product {

    public Wine(String name, int dateOfManufacture) {
        super(name, 3 * 365, dateOfManufacture);
    }
}

class Cheese extends Product {

    public Cheese(String name, int dateOfManufacture) {
        super(name, 10, dateOfManufacture);
    }
}

class Egg extends Product {

    public Egg(String name, int dateOfManufacture) {
        super(name, 2, dateOfManufacture);
    }
}

class Kitchen {

    ArrayList<Product> contents = new ArrayList<>();

    ArrayList<Product> getContents() {
        return contents;
    }

    public void addProduct(Product newProduct) {
        contents.add(newProduct);
    }

    public void removeProduct(Product p) {
        contents.remove(p);
    }

    public void sortByDaysLeft() {
        Collections.sort(contents, new Comparator<Product>() {

            @Override
            public int compare(Product p1, Product p2) {
                return ((Integer)p1.getDaysTillExpiration()).compareTo(
                        p2.getDaysTillExpiration());
            }
        });
    }

    public Product getEarliestExpiringProduct() {
        sortByDaysLeft();
        return contents.get(0);
    }
}

<强>输出：

Name: Big Egg, Days Left: 2

这是一个工作版本，尝试弄清楚它是如何工作的（并停止重新发布相同的问题）特别是Comparator<Product>，这将帮助您“排序厨房”并让您回归即将到期的产品。有关Comparator的更多信息。

注意：这不使用dateOfManufacture 如果您打算使用dateOfManufacture，则应将其声明为Date而不是int。

在厨房找到即将到期的产品

2 个答案: