feat: implement bank account system with audit logging and support for multiple account types

Author: bryanasb251

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

@@ -0,0 +1,23 @@
+package com.codedifferently.lesson17.bank;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+
+/**
+ * Creates a new saving account.
+ *
+ * @param accountNumber The account number as log transaction key.
+ * @param value The actual debit/credit transaction.
+ * @param accountNumberByValueLog The audit log object.
+ */
+public class AuditLog {
+
+  // Method to add a value to an existing ArrayList or create a new one if accountNumber doesn't
+  // exist
+  public void addToMap(
+      HashMap<String, ArrayList<Double>> accountNumberByValueLog,
+      String accountNumber,
+      Double value) {
+    accountNumberByValueLog.computeIfAbsent(accountNumber, k -> new ArrayList<>()).add(value);
+  }
+}

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

@@ -0,0 +1,47 @@
+package com.codedifferently.lesson17.bank;
+
+import java.util.HashSet;
+import java.util.Set;
+
+public abstract class BankAccount {
+  protected String accountNumber;
+  protected Set<Customer> owners;
+  protected double balance;
+  protected boolean closed;
+
+  public BankAccount(String accountNumber, Customer owner) {
+    this.accountNumber = accountNumber;
+    this.owners = new HashSet<>(Set.of(owner));
+    this.balance = 0.0;
+    this.closed = false;
+    owner.addAccount(this);
+  }
+
+  public String getAccountNumber() {
+    return accountNumber;
+  }
+
+  public Set<Customer> getOwners() {
+    return owners;
+  }
+
+  public double getBalance() {
+    return balance;
+  }
+
+  public boolean isClosed() {
+    return closed;
+  }
+
+  public void deposit(double amount) {
+    balance += amount;
+  }
+
+  public void withdraw(double amount) {
+    balance -= amount;
+  }
+
+  public void closeAccount() {
+    closed = true;
+  }
+}

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

@@ -10,21 +10,17 @@
 public class BankAtm {
 
   private final Map<UUID, Customer> customerById = new HashMap<>();
-  private final Map<String, CheckingAccount> accountByNumber = new HashMap<>();
+  private final Map<String, BankAccount> accountByNumber = new HashMap<>();
+  private final AuditLog auditLog = new AuditLog();
 
   /**
    * Adds a checking account to the bank.
    *
    * @param account The account to add.
    */
-  public void addAccount(CheckingAccount account) {
+  public void addAccount(BankAccount account) {
     accountByNumber.put(account.getAccountNumber(), account);
-    account
-        .getOwners()
-        .forEach(
-            owner -> {
-              customerById.put(owner.getId(), owner);
-            });
+    account.getOwners().forEach(owner -> customerById.put(owner.getId(), owner));
   }
 
   /**
@@ -33,7 +29,7 @@ public void addAccount(CheckingAccount account) {
    * @param customerId The ID of the customer.
    * @return The unique set of accounts owned by the customer.
    */
-  public Set<CheckingAccount> findAccountsByCustomerId(UUID customerId) {
+  public Set<BankAccount> findAccountsByCustomerId(UUID customerId) {
     return customerById.containsKey(customerId)
         ? customerById.get(customerId).getAccounts()
         : Set.of();
@@ -46,8 +42,9 @@ public Set<CheckingAccount> findAccountsByCustomerId(UUID customerId) {
    * @param amount The amount to deposit.
    */
   public void depositFunds(String accountNumber, double amount) {
-    CheckingAccount account = getAccountOrThrow(accountNumber);
+    BankAccount account = getAccountOrThrow(accountNumber);
     account.deposit(amount);
+    auditLog.record("Deposited $" + amount + " to account " + accountNumber);
   }
 
   /**
@@ -57,8 +54,9 @@ public void depositFunds(String accountNumber, double amount) {
    * @param check The check to deposit.
    */
   public void depositFunds(String accountNumber, Check check) {
-    CheckingAccount account = getAccountOrThrow(accountNumber);
+    BankAccount account = getAccountOrThrow(accountNumber);
     check.depositFunds(account);
+    auditLog.record("Deposited check of $" + check.getAmount() + " into account " + accountNumber);
   }
 
   /**
@@ -68,8 +66,9 @@ public void depositFunds(String accountNumber, Check check) {
    * @param amount
    */
   public void withdrawFunds(String accountNumber, double amount) {
-    CheckingAccount account = getAccountOrThrow(accountNumber);
+    BankAccount account = getAccountOrThrow(accountNumber);
     account.withdraw(amount);
+    auditLog.record("Withdrew $" + amount + " from account " + accountNumber);
   }
 
   /**
@@ -78,8 +77,8 @@ public void withdrawFunds(String accountNumber, double amount) {
    * @param accountNumber The account number.
    * @return The account.
    */
-  private CheckingAccount getAccountOrThrow(String accountNumber) {
-    CheckingAccount account = accountByNumber.get(accountNumber);
+  private BankAccount getAccountOrThrow(String accountNumber) {
+    BankAccount account = accountByNumber.get(accountNumber);
     if (account == null || account.isClosed()) {
       throw new AccountNotFoundException("Account not found");
     }

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

@@ -1,6 +1,6 @@
 package com.codedifferently.lesson17.bank;
 
-import com.codedifferently.lesson17.bank.exceptions.CheckVoidedException;
+// Correct import
 
 /** Represents a check. */
 public class Check {
@@ -45,13 +45,11 @@ public void voidCheck() {
    *
    * @param toAccount The account to deposit the check into.
    */
-  public void depositFunds(CheckingAccount toAccount) {
-    if (isVoided) {
-      throw new CheckVoidedException("Check is voided");
+  public void depositFunds(BankAccount account) {
+    if (account instanceof SavingsAccount) {
+      throw new UnsupportedOperationException("Cannot deposit checks into a savings account");
     }
-    account.withdraw(amount);
-    toAccount.deposit(amount);
-    voidCheck();
+    account.deposit(amount);
   }
 
   @Override

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

@@ -1,10 +1,14 @@
-package com.codedifferently.lesson17.bank;
+ package com.codedifferently.lesson17.bank;
 
-import com.codedifferently.lesson17.bank.exceptions.InsufficientFundsException;
 import java.util.Set;
+import com.codedifferently.lesson17.bank.exceptions.InsufficientFundsException;
+
+import main.java.com.codedifferently.lesson17.bank.BankAccount;
+
+public class CheckingAccount extends BankAccount {
 
-/** Represents a checking account. */
-public class CheckingAccount {
+    public CheckingAccount(String accountNumber, Set<Customer> owners, double initialBalance) {
+        super(accountNumber, owners, initialBalance);{
 
   private final Set<Customer> owners;
   private final String accountNumber;
@@ -128,4 +132,19 @@ public String toString() {
         + isActive
         + '}';
   }
+     @Override
+    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;
+    }
+
 }
+

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

@@ -11,6 +11,18 @@ public class Customer {
   private final String name;
   private final Set<CheckingAccount> accounts = new HashSet<>();
 
+  private boolean isBusiness;
+
+  public Customer(String name, boolean isBusiness) {
+    this.name = name;
+    this.id = UUID.randomUUID();
+    this.isBusiness = isBusiness;
+  }
+
+  public boolean isBusiness() {
+    return isBusiness;
+  }
+
   /**
    * Creates a new customer.
    *

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

@@ -0,0 +1,13 @@
+package com.codedifferently.lesson17.bank;
+
+import java.util.Set;
+
+/** A savings account does not support checks. */
+public class SavingsAccount extends BankAccount {
+
+  public SavingsAccount(String accountNumber, Set<Customer> owners, double initialBalance) {
+    super(accountNumber, owners, initialBalance);
+  }
+
+  // No check support = no extra method needed!
+}