feat: adds 2 new features for lesson_17 bankATM

Author: KerryFerguson04

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

@@ -1,21 +1,74 @@
 package com.codedifferently.lesson17.bank;
 
-import com.codedifferently.lesson17.bank.exceptions.AccountNotFoundException;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Set;
 import java.util.UUID;
 
-/** Represents a bank ATM. */
+import com.codedifferently.lesson17.bank.exceptions.AccountNotFoundException;
+
+/** 
+ * Represents a bank ATM system that manages customer accounts and transactions.
+ * 
+ * <p>This ATM supports various types of checking accounts including standard
+ * {@link CheckingAccount} and specialized {@link BusinessCheckingAccount} instances.
+ * The system uses polymorphism to treat all account types uniformly, enabling
+ * seamless operations regardless of the specific account implementation.
+ * 
+ * <p>Supported operations include:
+ * <ul>
+ *   <li>Adding accounts to the system</li>
+ *   <li>Finding accounts by customer ID</li>
+ *   <li>Depositing funds (cash or check) with multi-currency support</li>
+ *   <li>Withdrawing funds</li>
+ * </ul>
+ * 
+ * <p>The ATM supports deposits in multiple currencies including USD, EUR, GBP, JPY,
+ * CAD, AUD, CHF, and CNY. All currency conversions are handled automatically using
+ * the integrated {@link CurrencyConverter}, with all account balances maintained in USD.
+ * 
+ * <p>The ATM maintains internal mappings of customers and accounts for efficient
+ * lookup operations and enforces business rules such as account existence validation.
+ * 
+ * @see CheckingAccount
+ * @see BusinessCheckingAccount
+ * @see Customer
+ * @see BusinessCustomer
+ * @see Currency
+ * @see CurrencyConverter
+ * @since 1.0
+ */
 public class BankAtm {
 
   private final Map<UUID, Customer> customerById = new HashMap<>();
   private final Map<String, CheckingAccount> accountByNumber = new HashMap<>();
+  private final CurrencyConverter currencyConverter;
+  
+  /**
+   * Creates a new BankAtm with default currency conversion support.
+   * 
+   * <p>Initializes the ATM system with an empty set of accounts and customers,
+   * and sets up currency conversion capabilities for multi-currency deposits.
+   */
+  public BankAtm() {
+    this.currencyConverter = new CurrencyConverter();
+  }
 
   /**
-   * Adds a checking account to the bank.
+   * Adds a checking account to the ATM system.
+   * 
+   * <p>This method accepts any type of checking account, including standard
+   * {@link CheckingAccount} and {@link BusinessCheckingAccount} instances.
+   * The account and all its owners are registered in the system for lookup operations.
+   * 
+   * <p>After adding an account, customers can perform transactions using the
+   * account number, and the account can be found using any owner's customer ID.
    *
-   * @param account The account to add.
+   * @param account The checking account to add (including business accounts)
+   * @throws NullPointerException if the account is null
+   * 
+   * @see BusinessCheckingAccount
+   * @see #findAccountsByCustomerId(UUID)
    */
   public void addAccount(CheckingAccount account) {
     accountByNumber.put(account.getAccountNumber(), account);
@@ -40,14 +93,31 @@ public Set<CheckingAccount> findAccountsByCustomerId(UUID customerId) {
   }
 
   /**
-   * Deposits funds into an account.
+   * Deposits funds into an account with automatic currency conversion to USD.
+   * 
+   * <p>This method accepts deposits in various currencies and automatically
+   * converts the amount to USD using current exchange rates before depositing
+   * into the account. All account balances are maintained in USD.
+   * 
+   * <p>Supported currencies include USD, EUR, GBP, JPY, CAD, AUD, CHF, and CNY.
+   * Exchange rates are managed by the internal {@link CurrencyConverter}.
+   * For USD deposits, the amount is deposited directly without conversion overhead.
    *
-   * @param accountNumber The account number.
-   * @param amount The amount to deposit.
+   * @param accountNumber The account number to deposit funds into
+   * @param amount The amount to deposit in the specified currency
+   * @param currency The currency of the deposit amount
+   * @throws AccountNotFoundException if the account is not found or is closed
+   * @throws IllegalArgumentException if the amount is negative
+   * @throws IllegalArgumentException if the currency is null
+   * @throws UnsupportedOperationException if the currency is not supported
+   * 
+   * @see Currency
+   * @see CurrencyConverter
    */
-  public void depositFunds(String accountNumber, double amount) {
+  public void depositFunds(String accountNumber, double amount, Currency currency) {
     CheckingAccount account = getAccountOrThrow(accountNumber);
-    account.deposit(amount);
+    double usdAmount = currencyConverter.convertToUsd(amount, currency);
+    account.deposit(usdAmount);
   }
 
   /**

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

@@ -0,0 +1,78 @@
+package com.codedifferently.lesson17.bank;
+
+import java.util.Set;
+
+/** 
+ * Represents a business checking account that extends the standard checking account functionality.
+ * 
+ * <p>A business checking account enforces that at least one owner must be a business customer
+ * ({@link BusinessCustomer}). This validation occurs during account creation and will throw
+ * an {@link IllegalArgumentException} if no business owners are present.
+ * 
+ * <p>All standard checking account operations are inherited from {@link CheckingAccount},
+ * including deposits, withdrawals, balance inquiries, and account closure functionality.
+ * 
+ * <p>Business accounts can be seamlessly integrated with the {@link BankAtm} system
+ * through polymorphism, requiring no changes to existing ATM operations.
+ * 
+ * @see CheckingAccount
+ * @see BusinessCustomer
+ * @see BankAtm
+ * @since 1.0
+ */
+public class BusinessCheckingAccount extends CheckingAccount {
+
+  /**
+   * Creates a new business checking account with validation for business ownership.
+   * 
+   * <p>This constructor validates that at least one owner in the provided set is a
+   * {@link BusinessCustomer}. If no business customers are found among the owners,
+   * an {@link IllegalArgumentException} is thrown.
+   * 
+   * <p>The account inherits all functionality from {@link CheckingAccount} including
+   * deposit/withdrawal operations, balance management, and account closure capabilities.
+   *
+   * @param accountNumber The unique account number for this business account
+   * @param owners The set of account owners, must contain at least one {@link BusinessCustomer}
+   * @param initialBalance The initial balance of the account (must be non-negative)
+   * @throws IllegalArgumentException if the owners set is empty or contains no business customers
+   * @throws IllegalArgumentException if the account number is null or empty
+   * @throws IllegalArgumentException if the initial balance is negative
+   * 
+   * @see BusinessCustomer
+   * @see CheckingAccount#CheckingAccount(String, Set, double)
+   */
+  public BusinessCheckingAccount(String accountNumber, Set<Customer> owners, double initialBalance) {
+    super(accountNumber, owners, initialBalance);
+    
+    // Validate that at least one owner is a business customer
+    boolean hasBusinessOwner = owners.stream()
+        .anyMatch(owner -> owner instanceof BusinessCustomer);
+    
+    if (!hasBusinessOwner) {
+      throw new IllegalArgumentException("Business checking account requires at least one business owner");
+    }
+  }
+
+  /**
+   * Returns a string representation of this business checking account.
+   * 
+   * <p>The string includes the account number, current balance, and active status,
+   * formatted specifically for business accounts to distinguish them from regular
+   * checking accounts in logging and debugging scenarios.
+   *
+   * @return A formatted string containing account details
+   */
+  @Override
+  public String toString() {
+    return "BusinessCheckingAccount{"
+        + "accountNumber='"
+        + getAccountNumber()
+        + '\''
+        + ", balance="
+        + getBalance()
+        + ", isActive="
+        + !isClosed()
+        + '}';
+  }
+}

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

@@ -0,0 +1,59 @@
+package com.codedifferently.lesson17.bank;
+
+import java.util.UUID;
+
+/** Represents a business customer of the bank. */
+public class BusinessCustomer extends Customer {
+
+  private final String businessName;
+  private final String taxId;
+
+  /**
+   * Creates a new business customer.
+   *
+   * @param id The ID of the business customer.
+   * @param businessName The name of the business.
+   * @param taxId The tax identification number of the business.
+   */
+  public BusinessCustomer(UUID id, String businessName, String taxId) {
+    super(id, businessName);
+    this.businessName = businessName;
+    this.taxId = taxId;
+  }
+
+  /**
+   * Gets the business name.
+   *
+   * @return The business name.
+   */
+  public String getBusinessName() {
+    return businessName;
+  }
+
+  /**
+   * Gets the tax identification number.
+   *
+   * @return The tax identification number.
+   */
+  public String getTaxId() {
+    return taxId;
+  }
+
+  /**
+   * Determines if this customer is a business.
+   *
+   * @return True, since this is a business customer.
+   */
+  public boolean isBusiness() {
+    return true;
+  }
+
+  @Override
+  public String toString() {
+    return "BusinessCustomer{"
+        + "id=" + getId()
+        + ", businessName='" + businessName + '\''
+        + ", taxId='" + taxId + '\''
+        + '}';
+  }
+}

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

@@ -0,0 +1,37 @@
+package com.codedifferently.lesson17.bank;
+
+/**
+ * Enumeration of supported currencies for banking transactions.
+ * 
+ * <p>This enum defines the various currencies that can be used for deposits
+ * and other banking operations. All currency amounts are converted to USD
+ * for internal account balance management.
+ * 
+ * @see CurrencyConverter
+ * @since 1.0
+ */
+public enum Currency {
+  /** United States Dollar (base currency) */
+  USD,
+  
+  /** Euro */
+  EUR,
+  
+  /** British Pound Sterling */
+  GBP,
+  
+  /** Japanese Yen */
+  JPY,
+  
+  /** Canadian Dollar */
+  CAD,
+  
+  /** Australian Dollar */
+  AUD,
+  
+  /** Swiss Franc */
+  CHF,
+  
+  /** Chinese Yuan */
+  CNY
+}