거래 금액에 대한 부호 표시 기능 추가

banking/src/main/java/io/github/gunkim/banking/BankingApplication.java

@@ -34,13 +34,13 @@ private void runTransactions(AccountTransactionManager accountTransactionManager
     }
 
     private void printTransactions(AccountTransactionManager accountTransactionManager) {
-        final DateTimeFormatter formatter = DateTimeFormatter.ofPattern("dd.MM.yyyy HH:mm:ss");
+        final var formatter = DateTimeFormatter.ofPattern("dd.MM.yyyy HH:mm:ss");
 
         System.out.printf("%-20s %-15s %-15s\n", "Date", "Amount", "Balance");
         for (Transaction transaction : accountTransactionManager.findAll(FIXED_MY_ACCOUNT_ID)) {
             System.out.printf("%-20s %-15s %-15s\n",
                     formatter.format(transaction.createdAt()),
-                    transaction.amount(),
+                    transaction.signedAmount(),
                     transaction.balance());
         }
     }

banking/src/main/java/io/github/gunkim/banking/domain/Transaction.java

@@ -21,6 +21,10 @@ public static Transaction of(AccountId accountId, TransactionType type, Money am
         );
     }
 
+    public String signedAmount() {
+        return type.prefix() + this.amount;
+    }
+
     @Override
     public int compareTo(Transaction transaction) {
         return this.createdAt.compareTo(transaction.createdAt);

banking/src/main/java/io/github/gunkim/banking/domain/TransactionType.java

@@ -1,5 +1,15 @@
 package io.github.gunkim.banking.domain;
 
 public enum TransactionType {
-    DEPOSIT, WITHDRAW
+    DEPOSIT("+"), WITHDRAW("-");
+
+    private final String prefix;
+
+    TransactionType(String prefix) {
+        this.prefix = prefix;
+    }
+
+    public String prefix() {
+        return prefix;
+    }
 }