lab6打卡

PART1:因为 readline函数抛出了异常没有处理，所以在main里面合适的地方加上try catch即可

PART2:在合适的地方加上BadAccountException

PART3：自己写一个BadTransactionException，形式和BadAccountException是差不多的，然后在主程序上，需要判断正负问题的函数处加上这个exception。

package lab6;
/*  VirtualTeller.java */

import sortedlist.*;

/**
 *  An implementation of a virtual automated teller machine.
 **/
public class VirtualTeller {
  private static int nextAccountID = 100;
  private SortedList accounts;

  /**
   *  Constructs a new virtual teller.
   **/
  public VirtualTeller() {
    accounts = new SortedList();
  }

  /**
   *  openAccount() creates a new account for the customer "name".
   *  @param name the customer's name.
   *  @return the new account's ID number.
   **/
  public int openAccount(String name) {
    AccountData newData = new AccountData(name, nextAccountID);
    accounts.insert(newData);

    nextAccountID++;
    return newData.getNumber();
  }

  /**
   *  withdraw() withdraws "amount" dollars from the account whose number is
   *  "acct".  Assumes that amount >= 0.  If "acct" is invalid, no action is
   *  taken.
   *  @param acct is an account number.
   *  @param amount an amount of money.
   */
  public void withdraw(int acct, int amount)throws BadAccountException,BadTransactionException {
    AccountData account = findAccount(acct);
    if(amount<0) {
        throw new BadTransactionException(amount);
    }
    //if (account == null) {   // Didn't find the account.
    //  System.out.println("Error:  Couldn't find account number `" +
    //                     acct + "'" );
    //} else {
      account.withdraw(amount);
    //}
                         
  }

  /**
   *  deposit() deposits "amount" dollars into the bank account whose number is
   *  "acct".  Assumes that amount >= 0.  If "acct" is invalid, no action is
   *  taken.
   *  @param acct is an account number.
   *  @param amount an amount of money.
   */
  public void deposit(int acct, int amount) throws BadAccountException,BadTransactionException {
    AccountData account = findAccount(acct);
    if(amount<0) {
        throw new BadTransactionException(amount);
    }
   // if (account == null) { 
   //  System.out.println("Error:  Couldn't find account number `" +
   //                     acct + "'");
   // } else {
      account.deposit(amount);
   //}
  }

  /**
   *  balanceInquiry() finds the balance on the account whose number is "acct".
   *  If "acct" is an invalid number, returns -1.
   *  @param acct an account number.
   *  @return the balance, or -1 if the account number is invalid.
   */
  public int balanceInquiry(int acct)throws BadAccountException {
    AccountData account = findAccount(acct);

    if (account == null) {
    //  System.out.println("Error:  Couldn't find account number `" +
    //                    acct + "'" );
      return -1;
    } else {
      return account.getBalance();
    }
  }

  /**
   *  findAccount() gets the AccountData object associated with account number
   *  "acct".  If "acct" does not refer to a valid account, returns null.
   *  @param acct is an account number.
   *  @return the AccountData object associated with the account number.
   */
  private AccountData findAccount(int acct) throws BadAccountException{
    AccountData account = (AccountData) accounts.find(acct);
    if(account==null) {
        throw new BadAccountException(acct);
    }
    return account;
  }
}

package lab6;
/* BankApp.java */

import java.io.*;
import sortedlist.*;

/**
 *  A bank application.  Allows a user to create and manipulate 
 *  banking accounts, using an ATM that is shared by all banking applications.
 */
public class BankApp {
  private BufferedReader bReader =
          new BufferedReader(new InputStreamReader(System.in));
  private VirtualTeller ATM = new VirtualTeller();

  public static void main(String[] args) {
    greeting();
    usage();
    BankApp bankApp = new BankApp();

    try {
        String command = bankApp.readLine("--> ");
        while (!command.equals("quit")) {
            try {
                if (command.equals("open")) {
                    bankApp.open();
                } else if (command.equals("deposit")) {
                    bankApp.doDeposit();
                } else if (command.equals("withdraw")) {
                    bankApp.doWithdraw();
                } else if (command.equals("inquire")) {
                    bankApp.doInquire();
                } else {
                    System.err.println("Invalid command: " + command);
                    usage();
                }
                }catch(BadTransactionException e2) {
                    System.err.println(e2);
                }catch(BadAccountException e1) {
                    System.err.println(e1);
                }catch(IOException e) {
                System.err.println(e);
                }
            command = bankApp.readLine("--> ");
        }
    }catch(IOException e) {
            System.err.println(e);
        }
  }
  public BankApp() {
    // The field declarations have initializers;
    //   no initialization is needed here.
  }

  /**
   *  open() prompts the user to create an account and creates one in the ATM.
   *  @exception IOException if there are problems reading user input.
   */
  private void open() throws IOException {
    String name = readLine("Enter name: ");
    int newNum = ATM.openAccount(name);

    System.out.println(name + ", your new account number is: " + newNum);
    System.out.println("Thanks for opening an account with us!");
  }

 /**
  *  doDeposit() prompts the user for an account number and tries to perform a 
  *  deposit transaction on that account. 
  *  @exception IOException if there are problems reading user input.
  */
  private void doDeposit() throws IOException, BadAccountException,BadTransactionException {
    // Get account number.
    int acctNumber = readInt("Enter account number: ");
    int amount = readInt("Enter amount to deposit: ");

    ATM.deposit(acctNumber, amount);
    System.out.println("New balance for #" + acctNumber + " is " +
                       ATM.balanceInquiry(acctNumber));
  }

  /**
   *  doWithdraw() prompts the user for an account number and tries
   *  to perform a withdrawal transaction from that account.
   *  @exception IOException if there are problems reading user input.
   */
  private void doWithdraw() throws IOException, BadAccountException,BadTransactionException {
    // Get account number.
    int acctNumber = readInt("Enter account number: ");
    int amount = readInt("Enter amount to withdraw: ");

    ATM.withdraw(acctNumber, amount);
    System.out.println("New balance for #" + acctNumber + " is " +
                       ATM.balanceInquiry(acctNumber));
  }

  /**
   *  doInquire() prompts the user for an account number, then attempts to
   *  discover and print that account's balance.
   *  @exception IOException if there are problems reading user input.
   */
  private void doInquire() throws IOException, BadAccountException {
    int acctNumber = readInt("Enter account number: ");

    System.out.println("Balance for #" + acctNumber + " is " +
                       ATM.balanceInquiry(acctNumber));
  }

  /**
   *  greeting() displays a greeting message on the screen.
   */
  private static void greeting() {
    System.out.println("-------------------");
    System.out.println("Welcome to the bank");
    System.out.println("-------------------");
    System.out.println();
  }

  /**
   *  usage() displays instructions on using the command line arguments.
   */
  private static void usage() {
    System.out.println("Valid commands are: " +
                       "open, deposit, withdraw, inquire, quit");
  }

  /**
   *  readLine() prints the given prompt and returns a string from the
   *  input stream.
   *  @param prompt is the string printed to prompt the user.
   */
  private String readLine(String prompt) throws IOException {
    System.out.print(prompt);
    System.out.flush();
    return bReader.readLine();
  }

  /**
   *  readInt() returns an integer from the input stream after prompting
   *  the user.
   *  @param prompt is the string printed to prompt the user.
   *  @return an int read from the user.
   */
  private int readInt(String prompt) throws IOException {
    String text = readLine(prompt);
    return Integer.valueOf(text).intValue();
  }
}