如何將ArrayList中對象的屬性與Scanner輸入進行比較？

Question

我在Eclipse控制台中運行了一個簡單的“ Supplier / Product” Java應用程序。

每個“供應商”對象都有一個“產品”對象的ArrayList。

public class Supplier {

private int supCode;
private String supName;
private Address supAddress;
private SupRegion supRegion;
private ArrayList<Product> supProducts;

public Supplier(int supCode, String supName, Address supAddress, SupRegion supRegion,
        ArrayList<Product> supProducts) {
    super();
    this.supCode = supCode;
    this.supName = supName;
    this.supAddress = supAddress;
    this.supRegion = supRegion;
    this.supProducts = supProducts;
}

然后，我還有另一個ArrayList，其中包含Supplier對象“ supDatabase”

在下面創建的運行時中只有2個供應商：

//Suppliers
Supplier hendys = new Supplier(101, "Hendersons" , add1, SupRegion.UNITED_KINGDOM, hendysPros); 
Supplier palasFoods = new Supplier(102, "Palas Foods", add2, SupRegion.UNITED_KINGDOM, palasPros);


ArrayList<Supplier> supDatabase = new ArrayList<Supplier>();

//method to add all products into ProductArrayList
//also to add all suppliers to SupplierArrayList
public ArrayList<Supplier> populateDatabase(ArrayList<Supplier> supDB) {

    hendysPros.add(remote);
    hendysPros.add(remote1);
    hendysPros.add(remote2);
    hendysPros.add(remote3);

    supDatabase.add(hendys);

    palasPros.add(strawberries);
    palasPros.add(raspberries);
    palasPros.add(blueberries);

    supDatabase.add(palasFoods);


    return supDatabase;
}

我現在正在嘗試添加功能以將新產品添加到特定的供應商。

以下方法嘗試將用戶輸入的供應商“代碼”與ArrayList（supDatabase）中的數據進行比較：

private static void addNewProduct(Scanner sc)
{       
    System.out.println("Enter supplier code you would like to add a product to: ");
    int choice = getUserInput(sc);

    //***PROBLEM*** - trying to validate whether the user has entered an existing Supplier code i.e.
    //does the integer entered match a Suppliers's code, contained within a Supplier object
    //which are then contained within an ArrayList (supDatabase)


    for (int i=0; i<supDB.supDatabase.size();i++)           //for loop to cycle through ArrayList of Supplier objects??
    {
        if (choice == supDB.supDatabase.get(i).getSupCode())
        {
            System.out.println("You have chosen to add a product to: " + supDB.supDatabase.get(i).getSupName());

            Product newProduct  = new Product(0, "", "", 0, 0, false);

            System.out.println("Enter a code for the new product: ");
            newProduct.setProCode(sc.nextInt());

            System.out.println("Enter make: ");
            newProduct.setProMake(sc.next());

            System.out.println("Enter model: ");
            newProduct.setProModel(sc.next());

            System.out.println("Enter price: ");
            newProduct.setProPrice(sc.nextDouble());

            System.out.println("Enter the quantity available: ");
            newProduct.setProQtyAvailable(sc.nextInt());

            System.out.println("Is the product available? (Y/N)");
            newProduct.setProDiscontinued(sc.hasNext());                    

            //add the new created Product to the database ArrayList
            supDB.supDatabase.get(i).getSupProducts().add(newProduct);
        }
        else
        {
            System.out.println("Supplier code not present. Try again");
        }
    }

}

比較僅適用於ArrayList中的第一個Supplier，並且無法識別超出該范圍的任何內容。 我知道這與addNewProduct（）的結構有關。

任何人都可以推薦任何重組或實際上我可以采用的其他任何技術？ （我意識到我現在使用的代碼是非常基本的，因此我可以使用任何新功能來整理工作！）

Answer 1

我建議您使用HashMap而不是ArrayList來存儲和查找供應商。 這是功能會有所不同的地方。

Map<Integer, Supplier> supDatabase = new HashMap<Integer, Supplier>();

//method to add all products into ProductArrayList
//also to add all suppliers to SupplierArrayList
public Map<Integer, Supplier> populateDatabase() {
    hendys.add(prod1);
    hendys.add(prod2);
    hendys.add(prod3);
    hendys.add(prod4);

    supDatabase.put(hendys.getSupCode(), hendys);

    palasFoods.add(strawberries);
    palasFoods.add(raspberries);
    palasFoods.add(blueberries);

    supDatabase.add(palasFoods.getSupCode(), palasFoods);


    return supDatabase;
}

假設您在Supplier對象中為供應商代碼定義了吸氣劑。

這將使addNewProduct如下所示：

private static void addNewProduct(Scanner sc)
{       
    System.out.println("Enter supplier code you would like to add a product to: ");
    int choice = getUserInput(sc);

    Map<Integer, Supplier> supDatabase = new HashMap<Integer, Supplier>();

    if (supDatabase.containsKey(sc)) {
        System.out.println("You have chosen to add a product to: " + supDB.supDatabase.get(i).getSupName());

        Product newProduct  = new Product(0, "", "", 0, 0, false);

        System.out.println("Enter a code for the new product: ");
        newProduct.setProCode(sc.nextInt());

        System.out.println("Enter make: ");
        newProduct.setProMake(sc.next());

        System.out.println("Enter model: ");
        newProduct.setProModel(sc.next());

        System.out.println("Enter price: ");
        newProduct.setProPrice(sc.nextDouble());

        System.out.println("Enter the quantity available: ");
        newProduct.setProQtyAvailable(sc.nextInt());

        System.out.println("Is the product available? (Y/N)");
        newProduct.setProDiscontinued(sc.hasNext());                    

        //add the new created Product to the database ArrayList
        supDatabase.get(sc).getSupProducts().add(newProduct);
    }
    else
    {
        System.out.println("Supplier code not present. Try again");
    }
}

發生錯誤時，如果您希望用戶重試，則可能需要將其放入循環中，以便它再次詢問用戶輸入。 如果沒有供應商或用戶想要退出，最好在其上放置一個計數器或退出循環。