從ArrayList獲取特定元素

Question

主要我這樣做： 首先，我創建一個名字，姓氏和編號的新客戶。 然後我創建兩個savingsAccounts，其金額，ID和利率。 然後我將這兩個savingsAccounts添加到新客戶。 最後，我將新客戶添加到銀行。

Customer newCustomer = new Customer(firstName, lastName, pnumber);  

SavingsAccount savingsAccount1 = new SavingsAccount(400, "1", 4); //400$ into account no.1, with interest 4% 
SavingsAccount savingsAccount2 = new SavingsAccount(300, "2", 3); 

newCustomer.addAccount(savingsAccount1); 
newCustomer.addAccount(savingsAccount2); 

bank.addCustomer(newCustomer); 

這裏是類銀行：

public class Bank { 
    String bankName;  
    private ArrayList<Customer> customers = new ArrayList<Customer>(); 

    Bank(String bankName) { 
     this.bankName = bankName; 
    } 

    public void addCustomer(Customer newCustomer) { 
     customers.add(newCustomer); 
    } 
} 

這裏是一流的客戶：

public class Customer { 
    private String firstName; 
    private String lastName; 
    private String number;  
    private ArrayList<Account> accounts; 

    Customer(String firstName, String lastName, String number) { 
     this.firstName = firstName; 
     this.lastName = lastName; 
     this.number = number; 
     this.accounts = new ArrayList<Account>(); 
    } 

    public void addAccount(SavingsAccount account) { 
     accounts.add(account); 
    } 

    public void addAccount(CreditAccount account) { 
     accounts.add(account); 
    } 

    public ArrayList<Account> getAccounts() { 
     return accounts; 
    } 
} 

這裏是類SavingsAccount（繼承類賬戶）：

public class SavingsAccount extends Account { 

    public SavingsAccount() {  
     super(); 
    } 

    public SavingsAccount(double bal, String id, double inte) { 
     super(bal, id, inte); 
    } 

    @Override 
    public void deposit(String number, String id, double amount) { 

    } 

    @Override 
    public void withdraw(String number, String id, double amount) { 

    } 

    @Override 
    public void transfer(String number, String id, double amount) { 

    } 

    @Override 
    public double getBalance() { 

    } 

    @Override 
    public String getAccountId() { 
     return accountId; 
    } 

    @Override 
    public double getInterest(){ 
     return interest; 
    } 
} 

我問題是： 如何在類SavingsAccount中編寫代碼來爲某個客戶存入，提取，轉賬某個客戶的資金？ 比方說，我想在他的賬號1上向客戶2存款500。

這應該是像savingsAccount.deposit（「2」，「1」，500）;

我只是不知道如何訪問客戶編號2，他的帳號1. 任何人都可以幫助我嗎？

Answer 1

你可以做的是在銀行類，一個方法：

public class Bank { 
    // Your stuff 
    // new method: 
    public boolean transfer(Account accountFrom, double amount, String nameTo, int account) { 
    //check if the balance can be deposit from the account 
    if(amount <= accountFrom.getBalance()) { 
     //Check if the person exists in the bank 
     String name = nameTo.split(" "); // name[0] is the first name, name[1] last name 

     boolean success = false; 
     for(Customer c: customers) { 
      if(c.getFirstName().equalsIgnoreCase(name[0]) && 
        c.getLastName().equalsIgnoreCase(name[1]) { 
       for(Account a : c.getAccounts()) { 
       if(a.getAccountId() == account) { 
        // Add it to the account 
        a.deposit(amount); 
        success = true; 
        break; 
       } 
       } 
       break; 
      } 
     } 

     // Deposit it from the account (That class should only keep track of money, so it 
     // only takes an argument to deposit or withdraw a value, the rest is done by the bank 
     // Only do this if money has been dsposited at the target account 
     if(success){ 
      accountFrom.withdraw(amount); 
      return true; 
     } 

    } 
    return false; 
    } 
} 

爲了做到這一點，你必須structurely更改設置。

有帳戶只管理資金，這些帳戶被添加到客戶。顧客是銀行和他自己之間溝通的人。最後，銀行與客戶進行溝通。

我希望這會幫助你在方向