Thread: Putting an exception in an method

Hello, long time no see!

Now my problem is the following, I have the following exception that I created

 
package banking;
 
public class NoSuchAccountException extends AccountException {
 
	public NoSuchAccountException(int accountNo) {
		super(message,accountNo);
 
 
	}
}

As you can tell, this exception tells us when there is no account with the searched account number.The question is where in this Account class do i implement this exception, and how do I check if the account with that account number exist, so that if it doesnt exist I can throw this exception.

 
package banking;
 
import io.In;
import io.Out;
import java.io.IllegalArgumentException;
 
class Account {
  final int accountNo;
  final Customer owner;
  final double overdraft;
 
  double balance = 0;
 
  private Account(int accountNo, Customer owner, double overdraft) {
    this.accountNo = accountNo;
    this.owner = owner;
    this.overdraft = overdraft;
  }
 
  void print() {	  
    Out.println("Kontonummer: " + accountNo);
    owner.print();
    Out.format("Kontostand: %.2f%nÜberziehungsrahmen: %.2f%n",
      balance, overdraft);
  }
   public int createAccount(String firstName, String lastName, String phone, double overdraft) throws BankServiceException {
    if (nOfAccounts == CAPACITY) 
		throw new BankServiceException("The maximum capacity has been reached!");
 
    // use nOfAccounts as accountNo and index to array
    Customer owner = new Customer(firstName, lastName, phone);
    Account account = new Account(nOfAccounts, owner, overdraft);
    accounts[nOfAccounts] = account;
    nOfAccounts++;
 
    return account.accountNo;
  }
  public boolean deposit(double amount) throws IllegalArgumentException {
    if (amount <= 0) {
		throws new IllegalArgumentException("Cannot deposit negative amounts!");
	}
	break;
	else {
    balance += amount;
    return true;
  }
 
  public boolean withdraw(double amount) throws OverdraftLimitReachedException {
    if (amount <= 0 ) {
		throw new OverdraftLimitReachedException("Cannot withdraw negative amounts!",accountNo);
		break;
	}
	  else if  !isCovered(amount)) {
	  return false;
  } else {
    balance -= amount;
    return true;
  }
 
  boolean isCovered(double amount) {
    return amount - overdraft <= balance;
  }
 
  boolean transfer(Account target, double amount) {
    boolean success = withdraw(amount);
    if (!success) return false;
 
    target.deposit(amount);
    return true;
  }
}

What I meant by implementing this exception is, which method should throw the exception.And the code create account creates valid account number.After you create an account you get the account number (starting from 0) and with every new account created the account number rises (the nOfAccount++). Hopefully it gives you some insight in what I'm trying to achive, basically I'm trying to check if an account number exists, and if not to throw this exception, and catch it later.

I dont really get that part with 2345

Oh okay,I'll try a few things and we will see what I get

Well okay after trying for quite a while this is what I've come up with

 
package banking;
 
import java.lang.IllegalArgumentException;
import io.In;
import io.Out;
 
class Banking {
  static final int CAPACITY = 100;
 
  final Account[] accounts = new Account[CAPACITY];
  int nOfAccounts = 0;
 
  int createAccount(String firstName, String lastName, String phone, double overdraft) throws BankServiceException {
    if (nOfAccounts == CAPACITY) {
		throw new BankServiceException("The maximum capacity has been reached");
	}
    Customer owner = new Customer(firstName, lastName, phone);
    Account account = new Account(nOfAccounts, owner, overdraft);
    accounts[nOfAccounts] = account;
    nOfAccounts++;
 
    return account.accountNo;
  }
 
  private Acount getAccount(accountNo) throws NoSuchAccountException {
  if (accountNo >= accounts.length || accounts[accountNo] == null) {
   throw new NoSuchAccountException();
  }
  return account;
}
 
 
  boolean deposit(int accountNo, double amount) {
    Account account = getAccount(accountNo);
    return account.deposit(amount);
  }
 
  public boolean withdraw(int accountNo, double amount) throws OverdraftLimitReachedException {
    if (amount > overdraft ) {
		throw new OverdraftLimitReachedException("The overdraft limit has been excedeed");
 
    Account account = accounts[accountNo];
    return account.withdraw(amount);
	}
  }
  public boolean transfer(int fromNo, int toNo, double amount) {
    if (fromNo < 0 || toNo < 0 ||
        fromNo >= nOfAccounts || toNo >= nOfAccounts) return false;
 
    Account from = accounts[fromNo];
    Account to = accounts[toNo];
    return from.transfer(to, amount);
  }
 
  public double getBalance(int accountNo) {
    if (accountNo < 0 || accountNo >= nOfAccounts) return 0;
 
    Account account = accounts[accountNo];
    return account.balance;
  }
 
  double getBalance() {
    double sum = 0;
 
    for (int i = 0; i < nOfAccounts; i++) {
      sum += accounts[i].balance;
    }
    return sum;
  }
 
  void print() {
    Out.println("---------- Bankauszug ----------");
 
    for (int i = 0; i < nOfAccounts; i++) {
      accounts[i].print();
      Out.println("--------------------------------");
    }
    Out.format("Bilanzsumme: %.2f%n", getBalance());
    Out.println("--------------------------------");
  }
 
  // --------------------- Optionaler Teil ---------------------
 
  public static void main(String[] args) {
    Banking banking = new Banking();
    char op;
 
    do {
      printMenu();
      op = readOperation();
 
      switch (op) {
        case 'a': {
          printTitle("Konto anlegen");
          String firstName = getString("Vorname");
          String lastName = getString("Nachname");
          String phone = getString("Telefonnummer");
          double overdraft = getDouble("Überziehungsrahmen");
 
          int accountNo = banking.createAccount(
            firstName, lastName, phone, overdraft);
          printMessage("Anlegen von Konto " + accountNo, accountNo != -1);
          break;
        }
        case 'e': {
          printTitle("Einzahlen");
          int accountNo = getInt("Kontonummer");
          double amount = getDouble("Einzahlungsbetrag");
 
          boolean success = banking.deposit(accountNo, amount);
          printMessage("Einzahlen", success);
          break;
        }
        case 'b': {
          printTitle("Abheben");
          int accountNo = getInt("Kontonummer");
          double amount = getDouble("Abhebungsbetrag");
 
          boolean success = banking.withdraw(accountNo, amount);
          printMessage("Abheben", success);
          break;
        }
        case 't': {
          printTitle("Überweisen");
          int fromNo = getInt("Von Kontonummer");
          int toNo = getInt("Auf Kontonummer");
          double amount = getDouble("Betrag");
 
          boolean success = banking.transfer(fromNo, toNo, amount);
          printMessage("Überweisen", success);
          break;
        }
        case 'd':
          banking.print();
          break;
        case 'q':
          Out.println("Beenden");
          break;
        default:
          Out.println("Ungültige Operation");
          break;
      }
    } while(op != 'q');
  }
 
  static void printMenu() {
    Out.println();
    Out.println("*********** Bankverwaltung ********");
    Out.println("Konto anlegen ................... a");
    Out.println("Einzahlen ....................... e");
    Out.println("Beheben ......................... b");
    Out.println("Überweisen ...................... t");
    Out.println("Übersicht drucken ............... d");
    Out.println("Beenden ......................... q");
    Out.print("Welche Menuoption? [a|e|b|t|d|q]: ");
  }
 
  static char readOperation() {
    char ch = Character.toLowerCase(In.readChar());
    In.readLine();
    return ch;
  }
 
  static void printTitle(String text) {
    Out.println("*** " + text + " ***");
  }
 
  static String getString(String text) {
    Out.print(text + ": ");
    return In.readLine();
  }
 
  static double getDouble(String text) {
    Out.print(text + ": ");
    return In.readDouble();
  }
 
  static int getInt(String text) {
    Out.print(text + ": ");
    return In.readInt();
  }
 
  static void printMessage(String operation, boolean success) {
    String message = success ?
      operation + " erfolgreich durchgeführt" :
      "Ungültige Operation";
    Out.println(message);
  }
}

Im getting this error:

banking\Banking.java:25: error: <identifier> expected
private Acount getAccount(accountNo) throws NoSuchAccountException {
^
1 error

Any help?

Yea the ^ was pointing to the wrong thing.Actually I've fixed the error.I was sussposed to give a type as a parameter (int accountNo). But now I'm facing a diffrent problem.

This error;

C:\Users\Hp\Desktop\ue9>javac banking/Banking.java
banking\Banking.java:29: error: cannot find symbol
  return account;

I've fixed the problem, this is how the code looks like, my return value was wrong.

 
  private Account getAccount(int accountNo) {
  if (accountNo >= accounts.length || accounts[accountNo] == null) {
   throw new NoSuchAccountException(accountNo);
  }
  return  accounts[nOfAccounts];
}

The code compiles without any errors I'll do some testing and I'll let you know!

Okay after quite a while I've managed to solve (at least I hope so) most of the errors in my code. But there is still this one error that I cannot solve.

 
public boolean withdraw(int accountNo, double amount) throws OverdraftLimitReachedException {
    if (amount > 0.0) {
		throw new OverdraftLimitReachedException(accountNo,amount,overdraft);
	}
    Account account = accounts[accountNo];
    return account.withdraw(amount);

It says it cannot find the simbol overdraft.I've tried adding it to the constructor as a parameter but than in the main method where I execute this method I get an error that the symbol cant be found.

Here is the error

banking\Banking.java:122: error: cannot find symbol
          boolean success = banking.withdraw(accountNo, amount,overdraft);
                                                                                               ^
  symbol:   variable overdraft
  location: class Banking
1 error
 
C:\Users\Hp\Desktop\ue9>

The overdraft variable is defined in class Account

 
Account(int accountNo, Customer owner, double overdraft) {
    this.accountNo = accountNo;
    this.owner = owner;
    this.overdraft = overdraft;
  }
 
  void print() {
    Out.println("Kontonummer: " + accountNo);
    owner.print();
    Out.format("Kontostand: %.2f%nÜberziehungsrahmen: %.2f%n",
      balance, overdraft);
  }
 
  boolean deposit(double amount) {
    if (amount <= 0) return false;
 
    balance += amount;
    return true;
  }
 
  boolean withdraw(double amount) {
    if (amount <= 0 || !isCovered(amount)) return false;
 
    balance -= amount;
    return true;
  }
 
  boolean isCovered(double amount) {
    return amount - overdraft <= balance;
  }
 
  boolean transfer(Account target, double amount) {
    boolean success = withdraw(amount);
    if (!success) return false;
 
    target.deposit(amount);
    return true;
  }
}

I dont think I get your first question. "Is that in scope where it is being used that caused the error?" what exactly does that mean.Yes I am also asking on stackoverflow about the same issue

Here is the link : https://stackoverflow.com/questions/...51592_62110285

I have found a great website explaining scope (https://www.java-made-easy.com/variable-scope.html). I will read through this carefully and try to adapt my code.