atm.java

Java 入门书的源码

//Copyright (c) 1998, Arthur Gittleman
//This example is provided WITHOUT ANY WARRANTY either expressed or implied.

/*  Illustrates object-oriented programming, identifying
 *  objects from scenarios for uses, and their methods
 *  from the responsibilities identified in the scenarios.
 *  The main method just constructs objects, which interact,
 *  providing the behavior they are responsible for.
 */
        
import personData.*;
import iopack.Io; 
class User {
  private Person me;
  private Teller teller;
  public User(Person p, Teller t) {
    me = p;
    teller = t;
    System.out.println("\nUser is \n" + p + "\n");
    teller.acceptCard(this);
  }
  public void enterPIN() {
    String pin = Io.readString("Enter your PIN");
    teller.acceptPIN(pin);
  } 
  public void selectTransaction() {
    int choice;
    do {
      System.out.println();  
      System.out.println("Choose a transaction");
      System.out.println("1.  Deposit");
      System.out.println("2.  Withdraw");
      System.out.println("3.  Cancel");
      System.out.println("4.  Get balance");
      choice = Io.readInt("Enter your choice, 1, 2, 3, or 4"); 
    } while (choice != 1 && choice != 2 && choice != 3 && choice != 4);       
    teller.acceptTransaction(choice);
  }
  public void selectType() {
    int choice;
    do {
      System.out.println();  
      System.out.println("Choose an account type");
      System.out.println("1.  Savings");
      System.out.println("2.  Checking");
      System.out.println("3.  Cancel");
      choice = Io.readInt("Enter your choice, 1, 2 or 3"); 
    } while (choice != 1 && choice != 2 && choice != 3);       
    teller.acceptType(choice);
  }
  public void specifyAmount() {
    double d = Io.readDouble("Enter an amount");
      teller.acceptAmount(d);
  } 
}
class Teller {
  public static final int DEPOSIT =1;
    public static final int WITHDRAW = 2;
    public static final int CANCEL = 3; 
    public static final int BALANCE = 4;
    String id;
    int transType;
    int  acctType;
    User user;
    Bank bank;
    Account account;  
    public Teller(Bank b) {
      bank = b;
    }
    public void acceptCard(User u) {
      user = u;
      user.enterPIN();
    }  
    public void acceptPIN(String s) {
      id = s;
      user.selectTransaction();
    }
    public void acceptTransaction(int trans) {
      transType = trans;
      if (transType != CANCEL)
        user.selectType();
    }
    public void acceptType(int type) {
      acctType = type;
      if (acctType != CANCEL)   
        bank.find(id,acctType,this);
    }
    public void acceptAccount(Account a) {
      account = a;   
      if (account != null)       
        if (transType == BALANCE){
           System.out.print("The balance is ");
           Io.println$(account.getBalance());
           user.selectTransaction();
        }   
        else {
           if (transType == DEPOSIT || transType == WITHDRAW)
                  user.specifyAmount();     
        }
      else {
        System.out.println("No such account"); 
        user.selectTransaction();
      }
    } 
    public void acceptAmount(double amount) {
      switch(transType) {
        case DEPOSIT :      
          account.deposit(amount);
          break;
        case WITHDRAW:  
          account.withdraw(amount);
          break;
      }
      user.selectTransaction();
    }
}
class Bank { 
  public static final int SAVINGS = 1;
  public static final int CHECKING = 2; 
  Name n1 = new Name("John","Venn");
  Address a1 = new Address( "123 Main St.", "Tyler","WY", "45654");
  Person p1 = new Person("123123123",n1,a1); 
  Name n2 = new Name("Mabel","Venn");
  Person p2 = new Person("456456456",n2,a1);
  Account p1Savings = new Savings(1500.00,p1,4.0);
  Account p1Checking = new Checking(p1,2500.00,.50);
  Account p2Savings = new Savings(1000.00,p2,3.5);

  public void find(String id, int acctType, Teller teller) {
    if (p1Savings.getId().equals(id) && acctType==SAVINGS)
       teller.acceptAccount(p1Savings);
    else if (p1Checking.getId().equals(id)&& acctType==CHECKING)
       teller.acceptAccount(p1Checking);
    else if (p2Savings.getId().equals(id) && acctType==SAVINGS)
       teller.acceptAccount(p2Savings);
    else
       teller.acceptAccount(null);
  }   
}
public class Atm {
  public static void main(String [] args) {
    Bank bank = new Bank();
    Teller teller = new Teller(bank); 
    User user1 = new User(bank.p1,teller);
    User user2 = new User(bank.p2,teller);
    Io.readString("Press any key to exit");   // Added for IDE use
  }
}
abstract class Account {
  private double balance; 
  private Person holder;                                                                 
  public Account(Person p)   {                                                                    
    this(0,p);
  }
  public Account(double initialAmount, Person p) {
    balance = initialAmount;
    holder = p;
  }
  public String getId() {
    return holder.getId();
  }    
  public void deposit(double amount) {                                             
    balance += amount;
  }
  public void withdraw(double amount) {
    if (balance >= amount)
       balance -= amount;
    else
       System.out.println("Insufficient funds");
  } 
  public double getBalance() {                                                         
    return balance;
  }
  public void setBalance(double amount) {
    balance = amount;
  }    
}
class Checking extends Account {  
  private double minBalance;
  private double charge;
  public Checking(Person p,double minAmount, double charge) {
    super(p);
    minBalance = minAmount;
    this.charge = charge;
  }
  public void processCheck(double amount)  {
    if (getBalance() >= minBalance)
      super.withdraw(amount);
    else 
      super.withdraw(amount + charge);      
  }
  public void withdraw(double amount) {
    processCheck(amount);
  }
} 
class Savings extends Account  {
  private double interestRate;
  public Savings(double amount, Person p, double rate) {
    super(amount,p);
    interestRate = rate;
  }     
  public void postInterest()  {
    double balance = getBalance();
    double interest = interestRate/100*balance;
    setBalance(balance + interest);
  }
}