feat: added BankAccount file and modified checking account class.

Author: NelltheWiz

lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/BankAccount.java

@@ -0,0 +1,115 @@
+package com.codedifferently.lesson17.bank;
+
+import java.util.Set;
+
+import com.codedifferently.lesson17.bank.exceptions.InsufficientFundsException;
+
+public class BankAccount {
+
+    protected Set<Customer> owners;
+    protected final String accountNumber;
+    protected double balance;
+    protected boolean isActive;
+
+    public BankAccount() {
+        this.owners = null;
+        this.accountNumber = "";
+    }
+
+    /**
+     * Gets the account number.
+     *
+     * @return The account number.
+     */
+    public String getAccountNumber() {
+        return accountNumber;
+    }
+
+    /**
+     * Gets the owners of the account.
+     *
+     * @return The owners of the account.
+     */
+    public Set<Customer> getOwners() {
+        return owners;
+    }
+
+    /**
+     * Deposits funds into the account.
+     *
+     * @param amount The amount to deposit.
+     */
+    public void deposit(double amount) throws IllegalStateException {
+        if (isClosed()) {
+            throw new IllegalStateException("Cannot deposit to a closed account");
+        }
+        if (amount <= 0) {
+            throw new IllegalArgumentException("Deposit amount must be positive");
+        }
+        balance += amount;
+    }
+
+    /**
+     * Withdraws funds from the account.
+     *
+     * @param amount
+     * @throws InsufficientFundsException
+     */
+    public void withdraw(double amount) throws InsufficientFundsException {
+        if (isClosed()) {
+            throw new IllegalStateException("Cannot withdraw from a closed account");
+        }
+        if (amount <= 0) {
+            throw new IllegalStateException("Withdrawal amount must be positive");
+        }
+        if (balance < amount) {
+            throw new InsufficientFundsException("Account does not have enough funds for withdrawal");
+        }
+        balance -= amount;
+    }
+
+    /**
+     * Gets the balance of the account.
+     *
+     * @return The balance of the account.
+     */
+    public double getBalance() {
+        return balance;
+    }
+
+    /** Closes the account. */
+    public void closeAccount() throws IllegalStateException {
+        if (balance > 0) {
+            throw new IllegalStateException("Cannot close account with a positive balance");
+        }
+        isActive = false;
+    }
+
+    /**
+     * Checks if the account is closed.
+     *
+     * @return True if the account is closed, otherwise false.
+     */
+    public boolean isClosed() {
+        return !isActive;
+    }
+
+    @Override
+    public int hashCode() {
+        return accountNumber.hashCode();
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj instanceof CheckingAccount other) {
+            return accountNumber.equals(other.accountNumber);
+        }
+        return false;
+    }
+
+    @Override
+    public String toString() {
+        return "CheckingAccount{" + "accountNumber='" + accountNumber + '\'' + ", balance=" + balance + ", isActive=" + isActive + '}';
+    }
+
+}

lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/CheckingAccount.java

@@ -4,7 +4,7 @@
 import java.util.Set;
 
 /** Represents a checking account. */
-public class CheckingAccount {
+public class CheckingAccount extends BankAccount{
 
   private final Set<Customer> owners;
   private final String accountNumber;