redis = conn.sync();
+
+ // 1. SETNX + TTL — 원자적 잠금
+ String result = redis.set(key, value,
+ SetArgs.Builder.nx().ex(distributedLock.ttlSeconds()));
+ if (!"OK".equals(result)) {
+ throw new LockAcquireFailedException(key);
+ }
+
+ try {
+ // 2. 실제 비즈니스 로직 (사용자 메서드)
+ return pjp.proceed();
+ } finally {
+ // 3. Lua script — 본인 락만 안전 해제
+ redis.eval(UNLOCK_LUA, ScriptOutputType.INTEGER,
+ new String[]{key}, value);
+ }
+ }
+ }
+
+ /** SpEL 로 메서드 인자 참조해서 키 동적 생성 (예: "wallet:#{fromId}") */
+ private String resolveKey(ProceedingJoinPoint pjp, String expression) {
+ MethodSignature signature = (MethodSignature) pjp.getSignature();
+ Method method = signature.getMethod();
+ MethodBasedEvaluationContext context = new MethodBasedEvaluationContext(
+ null, method, pjp.getArgs(), paramDiscoverer);
+ // "wallet:#{fromId}" → "wallet:1" (SpEL template 모드)
+ return parser.parseExpression(expression, templateContext).getValue(context, String.class);
+ }
+
+ public static class LockAcquireFailedException extends RuntimeException {
+ public LockAcquireFailedException(String key) {
+ super("락 획득 실패 — key=" + key);
+ }
+ }
+}
diff --git a/topics/06-event/members/chanhyeok/src/main/java/domain/P2PWallet.java b/topics/06-event/members/chanhyeok/src/main/java/domain/P2PWallet.java
new file mode 100644
index 0000000..a19fd6f
--- /dev/null
+++ b/topics/06-event/members/chanhyeok/src/main/java/domain/P2PWallet.java
@@ -0,0 +1,299 @@
+package domain;
+
+import java.math.BigDecimal;
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+
+/**
+ * P2P 송금 도메인 — 3 주차 락 학습용.
+ *
+ * row 3 개 동시 변경
+ * 송금 1 건 처리 시 다음 row 가 한 트랜잭션 안에서 모두 변경되어야 정합성 유지:
+ *
+ * - user_wallet 송금자 — balance ↓ + daily_sent_amount ↑
+ * - user_wallet 수취자 — balance ↑
+ * - fee_revenue (id=1) — total_collected ↑ (핫스팟)
+ * - transfer_log — INSERT 1 건
+ *
+ *
+ * 락 순서 (데드락 회피)
+ * {@code min(fromId, toId) → max(fromId, toId) → fee_revenue(id=1)}.
+ * 모든 트랜잭션이 동일한 순서로 락을 잡으면 순환 대기 X → 데드락 X.
+ *
+ * read-modify-write 패턴 강제
+ * {@code SELECT balance, daily_sent_amount} → 앱에서 검증 → {@code UPDATE} 로 짠다.
+ * {@code UPDATE balance = balance - ?} 같은 atomic UPDATE 로 짜면
+ * PG row-lock 이 자동으로 막아서 락 학습 포인트가 안 보임 (1, 2 주차 동일 원칙).
+ *
+ * 일일 한도 검증
+ * 잔액 검증 + 일일 한도 검증 2 단계 (RMW 단계 추가). 한도 초과 시 false 반환.
+ */
+public class P2PWallet {
+
+ /** 1 일 송금 한도 — RMW 검증 대상 */
+ public static final BigDecimal DAILY_LIMIT = new BigDecimal("500000");
+ /** 송금 수수료 — 측정 단순화를 위해 고정 */
+ public static final BigDecimal FEE = new BigDecimal("10");
+
+ private static final String SELECT_WALLET_FOR_UPDATE_SQL =
+ "SELECT balance, daily_sent_amount FROM user_wallet WHERE id = ? FOR UPDATE";
+
+ private static final String SELECT_WALLET_VERSION_SQL =
+ "SELECT balance, daily_sent_amount, version FROM user_wallet WHERE id = ?";
+
+ private static final String SELECT_FEE_FOR_UPDATE_SQL =
+ "SELECT total_collected FROM fee_revenue WHERE id = 1 FOR UPDATE";
+
+ private static final String SELECT_FEE_VERSION_SQL =
+ "SELECT total_collected, version FROM fee_revenue WHERE id = 1";
+
+ private static final String UPDATE_WALLET_SQL =
+ "UPDATE user_wallet SET balance = ?, daily_sent_amount = ? WHERE id = ?";
+
+ private static final String UPDATE_WALLET_OPTIMISTIC_SQL =
+ "UPDATE user_wallet SET balance = ?, daily_sent_amount = ?, version = version + 1 " +
+ "WHERE id = ? AND version = ?";
+
+ private static final String UPDATE_FEE_SQL =
+ "UPDATE fee_revenue SET total_collected = ? WHERE id = 1";
+
+ private static final String UPDATE_FEE_OPTIMISTIC_SQL =
+ "UPDATE fee_revenue SET total_collected = ?, version = version + 1 " +
+ "WHERE id = 1 AND version = ?";
+
+ private static final String INSERT_LOG_SQL =
+ "INSERT INTO transfer_log (from_id, to_id, amount, fee) VALUES (?, ?, ?, ?)";
+
+ /**
+ * 비관적 락 — row 3 개를 정해진 순서로 잠근다.
+ *
+ * @return 성공 시 true. 잔액 부족 / 일일 한도 초과 시 false.
+ */
+ public boolean transferPessimistic(Connection conn, long fromId, long toId, BigDecimal amount)
+ throws SQLException {
+
+ long lockFirst = Math.min(fromId, toId);
+ long lockSecond = Math.max(fromId, toId);
+
+ Wallet first = selectForUpdate(conn, lockFirst);
+ Wallet second = selectForUpdate(conn, lockSecond);
+ BigDecimal feeTotal = selectFeeForUpdate(conn);
+
+ Wallet from = (fromId == lockFirst) ? first : second;
+ Wallet to = (toId == lockFirst) ? first : second;
+
+ if (from.balance.compareTo(amount.add(FEE)) < 0) return false;
+ if (from.dailySent.add(amount).compareTo(DAILY_LIMIT) > 0) return false;
+
+ updateWallet(conn, fromId, from.balance.subtract(amount).subtract(FEE), from.dailySent.add(amount));
+ updateWallet(conn, toId, to.balance.add(amount), to.dailySent);
+ updateFee(conn, feeTotal.add(FEE));
+ insertLog(conn, fromId, toId, amount, FEE);
+ return true;
+ }
+
+ /**
+ * 낙관적 락 — 3 개 row 의 version 비교 후 UPDATE. 충돌 시 재시도.
+ *
+ * partial update (일부 row UPDATE 성공 / 일부 실패) 시 반드시 rollback —
+ * 안 그러면 다음 attempt 가 부분 반영된 상태를 다시 읽어서 정합성 깨짐.
+ *
+ * @return 성공 시 true. 잔액 부족 / 한도 초과 / 재시도 한계 초과 시 false (starvation).
+ */
+ public boolean transferOptimistic(Connection conn, long fromId, long toId,
+ BigDecimal amount, int maxRetries) throws SQLException {
+
+ for (int attempt = 0; attempt < maxRetries; attempt++) {
+ WalletV from = selectWithVersion(conn, fromId);
+ WalletV to = selectWithVersion(conn, toId);
+ FeeV feeV = selectFeeWithVersion(conn);
+
+ if (from.balance.compareTo(amount.add(FEE)) < 0) return false;
+ if (from.dailySent.add(amount).compareTo(DAILY_LIMIT) > 0) return false;
+
+ int affFrom = updateWalletOptimistic(conn, fromId,
+ from.balance.subtract(amount).subtract(FEE),
+ from.dailySent.add(amount),
+ from.version);
+ if (affFrom != 1) {
+ // fromId 변경 X — rollback 불필요. 재시도.
+ continue;
+ }
+
+ int affTo = updateWalletOptimistic(conn, toId,
+ to.balance.add(amount), to.dailySent, to.version);
+ if (affTo != 1) {
+ // ⚠️ partial — fromId 이미 차감. rollback 안 하면 정합성 깨짐.
+ conn.rollback();
+ continue;
+ }
+
+ int affFee = updateFeeOptimistic(conn, feeV.total.add(FEE), feeV.version);
+ if (affFee != 1) {
+ // ⚠️ partial — 두 wallet 이미 변경. rollback 필수.
+ conn.rollback();
+ continue;
+ }
+
+ insertLog(conn, fromId, toId, amount, FEE);
+ return true;
+ }
+ return false;
+ }
+
+ /**
+ * 락 없이 RMW (분산락 stage 에서 외부 락 잡고 호출).
+ */
+ public boolean transferRaw(Connection conn, long fromId, long toId, BigDecimal amount)
+ throws SQLException {
+
+ Wallet from = selectWallet(conn, fromId);
+ Wallet to = selectWallet(conn, toId);
+ BigDecimal feeTotal = selectFee(conn);
+
+ if (from.balance.compareTo(amount.add(FEE)) < 0) return false;
+ if (from.dailySent.add(amount).compareTo(DAILY_LIMIT) > 0) return false;
+
+ updateWallet(conn, fromId, from.balance.subtract(amount).subtract(FEE), from.dailySent.add(amount));
+ updateWallet(conn, toId, to.balance.add(amount), to.dailySent);
+ updateFee(conn, feeTotal.add(FEE));
+ insertLog(conn, fromId, toId, amount, FEE);
+ return true;
+ }
+
+ // ---- read helpers ----
+
+ private Wallet selectForUpdate(Connection conn, long id) throws SQLException {
+ try (PreparedStatement ps = conn.prepareStatement(SELECT_WALLET_FOR_UPDATE_SQL)) {
+ ps.setLong(1, id);
+ try (ResultSet rs = ps.executeQuery()) {
+ rs.next();
+ return new Wallet(rs.getBigDecimal(1), rs.getBigDecimal(2));
+ }
+ }
+ }
+
+ private Wallet selectWallet(Connection conn, long id) throws SQLException {
+ try (PreparedStatement ps = conn.prepareStatement(
+ "SELECT balance, daily_sent_amount FROM user_wallet WHERE id = ?")) {
+ ps.setLong(1, id);
+ try (ResultSet rs = ps.executeQuery()) {
+ rs.next();
+ return new Wallet(rs.getBigDecimal(1), rs.getBigDecimal(2));
+ }
+ }
+ }
+
+ private WalletV selectWithVersion(Connection conn, long id) throws SQLException {
+ try (PreparedStatement ps = conn.prepareStatement(SELECT_WALLET_VERSION_SQL)) {
+ ps.setLong(1, id);
+ try (ResultSet rs = ps.executeQuery()) {
+ rs.next();
+ return new WalletV(rs.getBigDecimal(1), rs.getBigDecimal(2), rs.getLong(3));
+ }
+ }
+ }
+
+ private BigDecimal selectFeeForUpdate(Connection conn) throws SQLException {
+ try (PreparedStatement ps = conn.prepareStatement(SELECT_FEE_FOR_UPDATE_SQL);
+ ResultSet rs = ps.executeQuery()) {
+ rs.next();
+ return rs.getBigDecimal(1);
+ }
+ }
+
+ private BigDecimal selectFee(Connection conn) throws SQLException {
+ try (PreparedStatement ps = conn.prepareStatement(
+ "SELECT total_collected FROM fee_revenue WHERE id = 1");
+ ResultSet rs = ps.executeQuery()) {
+ rs.next();
+ return rs.getBigDecimal(1);
+ }
+ }
+
+ private FeeV selectFeeWithVersion(Connection conn) throws SQLException {
+ try (PreparedStatement ps = conn.prepareStatement(SELECT_FEE_VERSION_SQL);
+ ResultSet rs = ps.executeQuery()) {
+ rs.next();
+ return new FeeV(rs.getBigDecimal(1), rs.getLong(2));
+ }
+ }
+
+ // ---- write helpers ----
+
+ private void updateWallet(Connection conn, long id, BigDecimal balance, BigDecimal dailySent)
+ throws SQLException {
+ try (PreparedStatement ps = conn.prepareStatement(UPDATE_WALLET_SQL)) {
+ ps.setBigDecimal(1, balance);
+ ps.setBigDecimal(2, dailySent);
+ ps.setLong(3, id);
+ ps.executeUpdate();
+ }
+ }
+
+ private int updateWalletOptimistic(Connection conn, long id, BigDecimal balance,
+ BigDecimal dailySent, long expectedVersion) throws SQLException {
+ try (PreparedStatement ps = conn.prepareStatement(UPDATE_WALLET_OPTIMISTIC_SQL)) {
+ ps.setBigDecimal(1, balance);
+ ps.setBigDecimal(2, dailySent);
+ ps.setLong(3, id);
+ ps.setLong(4, expectedVersion);
+ return ps.executeUpdate();
+ }
+ }
+
+ private void updateFee(Connection conn, BigDecimal newTotal) throws SQLException {
+ try (PreparedStatement ps = conn.prepareStatement(UPDATE_FEE_SQL)) {
+ ps.setBigDecimal(1, newTotal);
+ ps.executeUpdate();
+ }
+ }
+
+ private int updateFeeOptimistic(Connection conn, BigDecimal newTotal, long expectedVersion)
+ throws SQLException {
+ try (PreparedStatement ps = conn.prepareStatement(UPDATE_FEE_OPTIMISTIC_SQL)) {
+ ps.setBigDecimal(1, newTotal);
+ ps.setLong(2, expectedVersion);
+ return ps.executeUpdate();
+ }
+ }
+
+ private void insertLog(Connection conn, long fromId, long toId, BigDecimal amount, BigDecimal fee)
+ throws SQLException {
+ try (PreparedStatement ps = conn.prepareStatement(INSERT_LOG_SQL)) {
+ ps.setLong(1, fromId);
+ ps.setLong(2, toId);
+ ps.setBigDecimal(3, amount);
+ ps.setBigDecimal(4, fee);
+ ps.executeUpdate();
+ }
+ }
+
+ // ---- 측정 후 검증용 ----
+
+ public BigDecimal balanceOf(Connection conn, long id) throws SQLException {
+ try (PreparedStatement ps = conn.prepareStatement(
+ "SELECT balance FROM user_wallet WHERE id = ?")) {
+ ps.setLong(1, id);
+ try (ResultSet rs = ps.executeQuery()) {
+ rs.next();
+ return rs.getBigDecimal(1);
+ }
+ }
+ }
+
+ public BigDecimal feeTotal(Connection conn) throws SQLException {
+ try (PreparedStatement ps = conn.prepareStatement(
+ "SELECT total_collected FROM fee_revenue WHERE id = 1");
+ ResultSet rs = ps.executeQuery()) {
+ rs.next();
+ return rs.getBigDecimal(1);
+ }
+ }
+
+ private record Wallet(BigDecimal balance, BigDecimal dailySent) {}
+ private record WalletV(BigDecimal balance, BigDecimal dailySent, long version) {}
+ private record FeeV(BigDecimal total, long version) {}
+}
diff --git a/topics/06-event/members/chanhyeok/src/main/java/domain/TransferAfterCommitListeners.java b/topics/06-event/members/chanhyeok/src/main/java/domain/TransferAfterCommitListeners.java
new file mode 100644
index 0000000..65a39b8
--- /dev/null
+++ b/topics/06-event/members/chanhyeok/src/main/java/domain/TransferAfterCommitListeners.java
@@ -0,0 +1,37 @@
+package domain;
+
+import org.springframework.transaction.event.TransactionPhase;
+import org.springframework.transaction.event.TransactionalEventListener;
+
+/**
+ * STAGE 3 — @TransactionalEventListener(AFTER_COMMIT) — commit 후만 호출.
+ *
+ *
STAGE 2 (동기) 와의 차이
+ *
+ * - publishEvent 시점 — 콜백 등록만 (listener 호출 X)
+ * - commit 성공 → listener 호출
+ * - rollback → listener 호출 안 됨 (자동 스킵) ✓
+ *
+ *
+ * 5 주차 → 6 주차 한계 해결의 본질
+ * 트랜잭션 결과 기반 자동 분기 — 외부 호출이 트랜잭션 commit 보장 후에만 실행.
+ *
+ * 등록
+ * @Component 없음 — STAGE 3 의 @SpringBootApplication 에서 명시적 @Bean 으로 등록.
+ */
+public class TransferAfterCommitListeners {
+
+ @TransactionalEventListener(phase = TransactionPhase.AFTER_COMMIT)
+ public void onAudit(TransferCompletedEvent e) {
+ System.out.println(" [AUDIT-AC] " + e.fromId() + " → " + e.toId()
+ + " amount=" + e.amount()
+ + " at=" + e.completedAt()
+ + " thread=" + Thread.currentThread().getName());
+ }
+
+ @TransactionalEventListener(phase = TransactionPhase.AFTER_COMMIT)
+ public void onNotify(TransferCompletedEvent e) {
+ System.out.println(" [NOTIFY-AC] 수신자 " + e.toId() + " 알림 발송"
+ + " thread=" + Thread.currentThread().getName());
+ }
+}
diff --git a/topics/06-event/members/chanhyeok/src/main/java/domain/TransferCompletedEvent.java b/topics/06-event/members/chanhyeok/src/main/java/domain/TransferCompletedEvent.java
new file mode 100644
index 0000000..d91ef94
--- /dev/null
+++ b/topics/06-event/members/chanhyeok/src/main/java/domain/TransferCompletedEvent.java
@@ -0,0 +1,28 @@
+package domain;
+
+import java.math.BigDecimal;
+import java.time.Instant;
+
+/**
+ * 송금 완료 이벤트 — 6 주차 publishEvent payload.
+ *
+ * 설계 원칙
+ *
+ * - record — 불변 + equals/hashCode/getter 자동 (Spring 4.2+ payload-only)
+ * - 도메인 전용 타입 — String / Long 같은 공통 타입 발행 시 타입 충돌 위험
+ * - 풍부한 payload — @Async listener 가 다른 스레드에서도 DB 재조회 없이 처리 가능
+ * - 과거형 이름 — 이미 일어난 사건. PlaceTransfer 같은 명령형 X
+ *
+ *
+ * 5 주차 → 6 주차 매핑
+ *
+ * - 5 주차 — TransferService.transfer() 안에서 @Audited 가 commit 전 감사 기록
+ * - 6 주차 — transfer() 끝에 publishEvent + AFTER_COMMIT listener 가 commit 후 감사
+ *
+ */
+public record TransferCompletedEvent(
+ long fromId,
+ long toId,
+ BigDecimal amount,
+ Instant completedAt
+) {}
diff --git a/topics/06-event/members/chanhyeok/src/main/java/domain/TransferEventListeners.java b/topics/06-event/members/chanhyeok/src/main/java/domain/TransferEventListeners.java
new file mode 100644
index 0000000..14e5a2a
--- /dev/null
+++ b/topics/06-event/members/chanhyeok/src/main/java/domain/TransferEventListeners.java
@@ -0,0 +1,34 @@
+package domain;
+
+import org.springframework.context.event.EventListener;
+
+/**
+ * STAGE 1/2 — 동기 @EventListener (= 5 주차 한계 그대로).
+ *
+ * 특징
+ *
+ * - publishEvent 시점에 즉시 호출 (commit 전, 동기)
+ * - rollback 시 이미 실행된 후 — 외부 호출 회수 불가
+ * - = 5 주차 @Audited 와 정확히 같은 한계
+ *
+ *
+ * 등록
+ * @Component 없음 — STAGE 1/2 의 @SpringBootApplication 에서 명시적 @Bean 으로 등록.
+ * STAGE 3 (TransferAfterCommitListeners) 와의 독립 보장.
+ */
+public class TransferEventListeners {
+
+ @EventListener
+ public void onAudit(TransferCompletedEvent e) {
+ System.out.println(" [AUDIT] " + e.fromId() + " → " + e.toId()
+ + " amount=" + e.amount()
+ + " at=" + e.completedAt()
+ + " thread=" + Thread.currentThread().getName());
+ }
+
+ @EventListener
+ public void onNotify(TransferCompletedEvent e) {
+ System.out.println(" [NOTIFY] 수신자 " + e.toId() + " 알림 발송"
+ + " thread=" + Thread.currentThread().getName());
+ }
+}
diff --git a/topics/06-event/members/chanhyeok/src/main/java/domain/TransferService.java b/topics/06-event/members/chanhyeok/src/main/java/domain/TransferService.java
new file mode 100644
index 0000000..b9cbf6c
--- /dev/null
+++ b/topics/06-event/members/chanhyeok/src/main/java/domain/TransferService.java
@@ -0,0 +1,101 @@
+package domain;
+
+import java.math.BigDecimal;
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.time.Instant;
+import javax.sql.DataSource;
+import org.springframework.context.ApplicationEventPublisher;
+import org.springframework.jdbc.datasource.DataSourceUtils;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+/**
+ * 6 주차 변환 — 5 주차 TransferService 에서 @Audited 제거 + @Transactional 적용 + publishEvent 추가.
+ *
+ * 5 주차 → 6 주차 변경점
+ *
+ * - @Audited 제거 — audit 책임이 TransferEventListeners 의 AFTER_COMMIT 으로 이동
+ * - conn 직접 관리 (setAutoCommit / commit / rollback) → @Transactional 로 Spring 위임
+ * - DataSourceUtils.getConnection — Spring 트랜잭션의 conn 받기 (같은 트랜잭션 유지)
+ * - publishEvent(TransferCompletedEvent) — 메서드 끝에서 발행
+ *
+ *
+ * 유지된 부분
+ *
+ * - @DistributedLock — 5 주차 그대로. 트랜잭션 바깥에서 락 잡음
+ * - P2PWallet.transferRaw — 송금 로직 그대로
+ *
+ */
+@Service
+public class TransferService {
+
+ private final DataSource dataSource;
+ private final ApplicationEventPublisher publisher;
+ private final P2PWallet wallet = new P2PWallet();
+
+ public TransferService(DataSource dataSource, ApplicationEventPublisher publisher) {
+ this.dataSource = dataSource;
+ this.publisher = publisher;
+ }
+
+ @DistributedLock(key = "wallet:#{#fromId}", ttlSeconds = 5)
+ @Transactional
+ public void transfer(long fromId, long toId, BigDecimal amount) {
+ Connection conn = DataSourceUtils.getConnection(dataSource);
+ try {
+ wallet.transferRaw(conn, fromId, toId, amount);
+ } catch (SQLException e) {
+ throw new RuntimeException(e);
+ } finally {
+ DataSourceUtils.releaseConnection(conn, dataSource);
+ }
+
+ // commit 후 처리는 TransferEventListeners 의 AFTER_COMMIT 으로
+ publisher.publishEvent(new TransferCompletedEvent(fromId, toId, amount, Instant.now()));
+ }
+
+ /**
+ * STAGE 2 한계 재현용 — 송금 + publishEvent 후 일부러 예외 → rollback.
+ *
+ * 관찰
+ *
+ * - INSERT / UPDATE 는 rollback 으로 취소됨 (DB 정상)
+ * - listener 는 publishEvent 시점에 이미 동기로 호출됨 (commit 전)
+ * - = 5 주차 @Audited 한계와 동일 — 외부 알림 회수 불가
+ *
+ */
+ @DistributedLock(key = "wallet:#{#fromId}", ttlSeconds = 5)
+ @Transactional
+ public void transferWithFailure(long fromId, long toId, BigDecimal amount) {
+ Connection conn = DataSourceUtils.getConnection(dataSource);
+ try {
+ wallet.transferRaw(conn, fromId, toId, amount);
+ } catch (SQLException e) {
+ throw new RuntimeException(e);
+ } finally {
+ DataSourceUtils.releaseConnection(conn, dataSource);
+ }
+
+ publisher.publishEvent(new TransferCompletedEvent(fromId, toId, amount, Instant.now()));
+
+ // ★ 일부러 예외 — rollback 시뮬레이션. publishEvent 후라 listener 는 이미 실행됨
+ throw new RuntimeException("의도적 실패 (rollback 학습용)");
+ }
+
+ public BigDecimal balanceOf(long id) {
+ try (Connection conn = dataSource.getConnection()) {
+ return wallet.balanceOf(conn, id);
+ } catch (SQLException e) {
+ throw new RuntimeException(e);
+ }
+ }
+
+ public BigDecimal feeTotal() {
+ try (Connection conn = dataSource.getConnection()) {
+ return wallet.feeTotal(conn);
+ } catch (SQLException e) {
+ throw new RuntimeException(e);
+ }
+ }
+}
diff --git a/topics/06-event/members/chanhyeok/src/main/java/infra/MeasurementLog.java b/topics/06-event/members/chanhyeok/src/main/java/infra/MeasurementLog.java
new file mode 100644
index 0000000..dcb65cb
--- /dev/null
+++ b/topics/06-event/members/chanhyeok/src/main/java/infra/MeasurementLog.java
@@ -0,0 +1,94 @@
+package infra;
+
+import java.io.IOException;
+import java.net.URL;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardOpenOption;
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+
+/**
+ * 측정 결과를 본인 폴더의 measurements.md 파일에 자동 누적 기록.
+ * (1, 2 주차 example 과 동일 패턴)
+ *
+ * 자동 위치 감지
+ * IntelliJ Working Directory 설정과 무관하게, 이 클래스의 실제 위치에서
+ * 위로 올라가며 build.gradle 가진 폴더를 찾아 그 안에 measurements.md 를 만든다.
+ *
+ * 3 주차 측정 필드
+ *
+ * - {@code save(stage, method, misses, millis)} — 단순 측정 (1 주차 호환)
+ * - {@code save(stage, method, misses, failed, millis)} — 실패/재시도 포함 (2, 3 주차)
+ *
+ *
+ * 3 주차에선 두 번째 시그니처 주로 사용. {@code failed} 자리에 비관 락의 데드락 횟수 /
+ * 낙관 락의 재시도 횟수 / 분산 락의 lock 획득 실패 모두 기록.
+ */
+public final class MeasurementLog {
+
+ private static final Path FILE = resolveFile();
+ private static final DateTimeFormatter TIME = DateTimeFormatter.ofPattern("MM-dd HH:mm");
+
+ private MeasurementLog() {}
+
+ public static void save(String stage, String method, double misses, double millis) {
+ try {
+ if (!Files.exists(FILE)) {
+ Files.writeString(FILE,
+ "# 측정 기록\n\n자동 누적. 옆에 해석 메모는 직접 추가하세요.\n\n");
+ }
+
+ String line = String.format("- [%s] %s · %s: 누락 %.1f / %.1fms%n",
+ LocalDateTime.now().format(TIME), stage, method, misses, millis);
+ Files.writeString(FILE, line, StandardOpenOption.APPEND);
+
+ System.out.println("→ " + FILE.toAbsolutePath() + " 에 기록됨");
+ } catch (IOException e) {
+ System.err.println("⚠️ measurements.md 기록 실패: " + e.getMessage());
+ }
+ }
+
+ public static void save(String stage, String method, double misses, double failed, double millis) {
+ try {
+ if (!Files.exists(FILE)) {
+ Files.writeString(FILE,
+ "# 측정 기록\n\n자동 누적. 옆에 해석 메모는 직접 추가하세요.\n\n");
+ }
+
+ String line = String.format("- [%s] %s · %s: 누락 %.1f / 실패 %.1f / %.1fms%n",
+ LocalDateTime.now().format(TIME), stage, method, misses, failed, millis);
+ Files.writeString(FILE, line, StandardOpenOption.APPEND);
+
+ System.out.println("→ " + FILE.toAbsolutePath() + " 에 기록됨");
+ } catch (IOException e) {
+ System.err.println("⚠️ measurements.md 기록 실패: " + e.getMessage());
+ }
+ }
+
+ private static Path resolveFile() {
+ try {
+ var domain = MeasurementLog.class.getProtectionDomain();
+ if (domain == null) return Path.of("measurements.md");
+ var codeSource = domain.getCodeSource();
+ if (codeSource == null) return Path.of("measurements.md");
+ URL location = codeSource.getLocation();
+ if (location == null) return Path.of("measurements.md");
+
+ Path start = Path.of(location.toURI());
+ if (Files.isRegularFile(start)) {
+ start = start.getParent();
+ }
+
+ Path current = start;
+ for (int i = 0; i < 10 && current != null; i++) {
+ if (Files.exists(current.resolve("build.gradle"))
+ || Files.exists(current.resolve("build.gradle.kts"))) {
+ return current.resolve("measurements.md");
+ }
+ current = current.getParent();
+ }
+ } catch (Exception ignored) {}
+ return Path.of("measurements.md");
+ }
+}
diff --git a/topics/06-event/members/chanhyeok/src/main/java/infra/RedisConfig.java b/topics/06-event/members/chanhyeok/src/main/java/infra/RedisConfig.java
new file mode 100644
index 0000000..4de2faf
--- /dev/null
+++ b/topics/06-event/members/chanhyeok/src/main/java/infra/RedisConfig.java
@@ -0,0 +1,19 @@
+package infra;
+
+import io.lettuce.core.RedisClient;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * Redis 클라이언트 Spring Bean 등록.
+ *
+ * 3 주차 {@code RedisClientFactory} 의 정적 싱글턴 → 4 주차 학습대로 {@code @Bean(destroyMethod="shutdown")} 한 줄.
+ */
+@Configuration
+public class RedisConfig {
+
+ @Bean(destroyMethod = "shutdown")
+ public RedisClient redisClient() {
+ return RedisClient.create("redis://localhost:6379");
+ }
+}
diff --git a/topics/06-event/members/chanhyeok/src/main/java/infra/SchemaBootstrap.java b/topics/06-event/members/chanhyeok/src/main/java/infra/SchemaBootstrap.java
new file mode 100644
index 0000000..c7e56bd
--- /dev/null
+++ b/topics/06-event/members/chanhyeok/src/main/java/infra/SchemaBootstrap.java
@@ -0,0 +1,82 @@
+package infra;
+
+import javax.sql.DataSource;
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.sql.Statement;
+
+/**
+ * P2P 송금 도메인 — 측정 전 상태 리셋 유틸.
+ *
+ *
왜 매번 리셋하나
+ * 1, 2 주차 측정 원칙과 동일 — 이전 측정 잔여 상태가 다음 측정에 영향을 주면
+ * 결과 해석이 어려워진다. 명시적 초기화 + 시드.
+ *
+ * 리셋 대상
+ *
+ * - user_wallet — 두 사용자 row (id=1, id=2). balance / daily_sent_amount / version 초기화
+ * - fee_revenue — 단일 row (id=1). total_collected / version 초기화
+ * - transfer_log — TRUNCATE (이전 측정 이력 제거)
+ *
+ *
+ * row 구성 이유
+ * user_wallet 2 개 → 데드락 학습 (양방향 송금에서 락 순서 깸).
+ * fee_revenue 1 개 → 핫스팟 학습 (모든 송금이 한 row 에 몰림).
+ */
+public final class SchemaBootstrap {
+
+ private SchemaBootstrap() {}
+
+ public static void reset(DataSource ds) throws SQLException {
+ try (Connection c = ds.getConnection(); Statement s = c.createStatement()) {
+
+ s.execute("""
+ CREATE TABLE IF NOT EXISTS user_wallet (
+ id BIGINT PRIMARY KEY,
+ balance NUMERIC NOT NULL,
+ daily_sent_amount NUMERIC NOT NULL DEFAULT 0,
+ version BIGINT NOT NULL DEFAULT 0
+ )
+ """);
+
+ s.execute("""
+ CREATE TABLE IF NOT EXISTS fee_revenue (
+ id BIGINT PRIMARY KEY,
+ total_collected NUMERIC NOT NULL,
+ version BIGINT NOT NULL DEFAULT 0
+ )
+ """);
+
+ s.execute("""
+ CREATE TABLE IF NOT EXISTS transfer_log (
+ id BIGSERIAL PRIMARY KEY,
+ from_id BIGINT NOT NULL,
+ to_id BIGINT NOT NULL,
+ amount NUMERIC NOT NULL,
+ fee NUMERIC NOT NULL,
+ created_at TIMESTAMPTZ NOT NULL DEFAULT now()
+ )
+ """);
+
+ // 시드 + 리셋
+ s.execute("""
+ INSERT INTO user_wallet (id, balance, daily_sent_amount, version)
+ VALUES (1, 1000000, 0, 0), (2, 1000000, 0, 0)
+ ON CONFLICT (id) DO UPDATE
+ SET balance = EXCLUDED.balance,
+ daily_sent_amount = 0,
+ version = 0
+ """);
+
+ s.execute("""
+ INSERT INTO fee_revenue (id, total_collected, version)
+ VALUES (1, 0, 0)
+ ON CONFLICT (id) DO UPDATE
+ SET total_collected = 0,
+ version = 0
+ """);
+
+ s.execute("TRUNCATE TABLE transfer_log RESTART IDENTITY");
+ }
+ }
+}
diff --git a/topics/06-event/members/chanhyeok/src/main/java/stage/Stage1Hello.java b/topics/06-event/members/chanhyeok/src/main/java/stage/Stage1Hello.java
new file mode 100644
index 0000000..7fec4db
--- /dev/null
+++ b/topics/06-event/members/chanhyeok/src/main/java/stage/Stage1Hello.java
@@ -0,0 +1,78 @@
+package stage;
+
+import domain.TransferEventListeners;
+import domain.TransferService;
+import infra.SchemaBootstrap;
+import java.math.BigDecimal;
+import javax.sql.DataSource;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.context.annotation.Bean;
+
+/**
+ * STAGE 1 — 본인 도메인 첫 진입.
+ *
+ * 5 주차 → 6 주차 가장 작은 변경
+ *
+ * - TransferService.@Audited 제거 + @Transactional 적용
+ * - transfer() 끝에 publishEvent(TransferCompletedEvent)
+ * - TransferEventListeners — @EventListener 두 개 (audit + notify) 동기
+ *
+ *
+ * 예상 출력 순서
+ *
+ * [TX] begin
+ * [LOCK] begin — wallet:1
+ * (실제 송금)
+ * [AUDIT] ← publishEvent 직후 즉시 (commit 전, 동기, 같은 스레드)
+ * [NOTIFY] ← 같은 시점
+ * [LOCK] release
+ * [TX] commit
+ *
+ *
+ * 이 시점의 한계 — 5 주차와 동일
+ * listener 가 commit 전 호출 → rollback 시 audit / notify 이미 실행됨.
+ * STAGE 2 에서 @TransactionalEventListener(AFTER_COMMIT) 으로 옮겨 해결.
+ *
+ * 실행
+ * ./gradlew run -PmainClass=stage.Stage1Hello
+ */
+@SpringBootApplication(scanBasePackages = {"domain", "infra"})
+public class Stage1Hello {
+
+ @Bean
+ public TransferEventListeners syncListeners() {
+ return new TransferEventListeners();
+ }
+
+ public static void main(String[] args) throws Exception {
+ ConfigurableApplicationContext ctx = SpringApplication.run(Stage1Hello.class, args);
+
+ DataSource ds = ctx.getBean(DataSource.class);
+ SchemaBootstrap.reset(ds);
+
+ TransferService svc = ctx.getBean(TransferService.class);
+
+ System.out.println();
+ System.out.println("=== STAGE 1 — TransferService + publishEvent + @EventListener 동기 ===");
+ System.out.println();
+
+ System.out.println("--- transfer(1 → 2, 100) 정상 송금 ---");
+ svc.transfer(1L, 2L, new BigDecimal("100"));
+
+ System.out.println();
+ System.out.println("--- balance / fee 확인 ---");
+ System.out.println(" id=1 잔액 = " + svc.balanceOf(1L));
+ System.out.println(" id=2 잔액 = " + svc.balanceOf(2L));
+ System.out.println(" fee 누적 = " + svc.feeTotal());
+
+ System.out.println();
+ System.out.println("[학습 포인트]");
+ System.out.println(" · publisher (transfer) + listener (audit/notify) 같은 스레드 = 동기");
+ System.out.println(" · listener 가 publishEvent 직후 즉시 실행 — commit 전");
+ System.out.println(" · 5 주차 @Audited 한계와 동일 — STAGE 2 에서 AFTER_COMMIT 으로 해결");
+
+ ctx.close();
+ }
+}
diff --git a/topics/06-event/members/chanhyeok/src/main/java/stage/Stage2BeforeCommitTrap.java b/topics/06-event/members/chanhyeok/src/main/java/stage/Stage2BeforeCommitTrap.java
new file mode 100644
index 0000000..f8e2da3
--- /dev/null
+++ b/topics/06-event/members/chanhyeok/src/main/java/stage/Stage2BeforeCommitTrap.java
@@ -0,0 +1,92 @@
+package stage;
+
+import domain.TransferEventListeners;
+import domain.TransferService;
+import infra.SchemaBootstrap;
+import java.math.BigDecimal;
+import javax.sql.DataSource;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.context.annotation.Bean;
+
+/**
+ * STAGE 2 — @EventListener 한계 재현 (= 5 주차 @Audited 한계 그대로).
+ *
+ * 시나리오
+ *
+ * - 정상 송금 — INSERT + listener 호출 + commit
+ * - 실패 송금 — INSERT + listener 호출 + 예외 → rollback (listener 는 이미 호출됨)
+ *
+ *
+ * 한계 재현 포인트
+ *
+ * transferWithFailure(1, 2, 50):
+ * INSERT / UPDATE — DB 변경
+ * publishEvent — listener 즉시 호출 (동기, commit 전)
+ * [AUDIT] — 감사 기록 (= 5 주차 @Audited 와 같음)
+ * [NOTIFY] — 알림 발송 (= 외부 시스템 회수 불가)
+ * throw RuntimeException
+ * (rollback) — DB 만 취소. listener 는 이미 실행됨.
+ *
+ *
+ * balance 검증
+ * 두 송금 후 — 정상 송금만 반영됐어야 함:
+ *
+ * - id=1 잔액 = 1000000 - 100 - 10 = 999890 (정상 송금만)
+ * - id=2 잔액 = 1000000 + 100 = 1000100
+ * - fee 누적 = 10 (정상 송금만)
+ *
+ *
+ * 해결 → STAGE 3 (AFTER_COMMIT)
+ *
+ * 실행
+ * ./gradlew run -PmainClass=stage.Stage2BeforeCommitTrap
+ */
+@SpringBootApplication(scanBasePackages = {"domain", "infra"})
+public class Stage2BeforeCommitTrap {
+
+ @Bean
+ public TransferEventListeners syncListeners() {
+ return new TransferEventListeners();
+ }
+
+ public static void main(String[] args) throws Exception {
+ ConfigurableApplicationContext ctx = SpringApplication.run(Stage2BeforeCommitTrap.class, args);
+
+ DataSource ds = ctx.getBean(DataSource.class);
+ SchemaBootstrap.reset(ds);
+
+ TransferService svc = ctx.getBean(TransferService.class);
+
+ System.out.println();
+ System.out.println("=== STAGE 2 — @EventListener 한계 (commit 전 호출 → rollback 무력) ===");
+
+ System.out.println();
+ System.out.println("--- (1) 정상 송금 transfer(1 → 2, 100) ---");
+ svc.transfer(1L, 2L, new BigDecimal("100"));
+
+ System.out.println();
+ System.out.println("--- (2) 실패 송금 transferWithFailure(1 → 2, 50) — 일부러 예외 ---");
+ try {
+ svc.transferWithFailure(1L, 2L, new BigDecimal("50"));
+ } catch (RuntimeException e) {
+ System.out.println(" [caller] 예외 잡음: " + e.getMessage());
+ }
+
+ System.out.println();
+ System.out.println("--- balance / fee 확인 ---");
+ System.out.println(" id=1 잔액 = " + svc.balanceOf(1L) + " (예상: 999890, 정상 송금만 반영)");
+ System.out.println(" id=2 잔액 = " + svc.balanceOf(2L) + " (예상: 1000100)");
+ System.out.println(" fee 누적 = " + svc.feeTotal() + " (예상: 10)");
+
+ System.out.println();
+ System.out.println("[학습 포인트] — 5 주차 한계 그대로 재현");
+ System.out.println(" · DB INSERT/UPDATE = rollback 으로 취소 ✓");
+ System.out.println(" · [AUDIT] / [NOTIFY] = publishEvent 시점에 이미 실행됨 ✗");
+ System.out.println(" · 실패 케이스에서도 사용자에게 \"송금 성공\" 알림 발송됨 (회수 불가)");
+ System.out.println(" · 해결 → STAGE 3 (@TransactionalEventListener(AFTER_COMMIT))");
+
+ ctx.close();
+ }
+}
diff --git a/topics/06-event/members/chanhyeok/src/main/java/stage/Stage3AfterCommit.java b/topics/06-event/members/chanhyeok/src/main/java/stage/Stage3AfterCommit.java
new file mode 100644
index 0000000..3b5f64f
--- /dev/null
+++ b/topics/06-event/members/chanhyeok/src/main/java/stage/Stage3AfterCommit.java
@@ -0,0 +1,83 @@
+package stage;
+
+import domain.TransferAfterCommitListeners;
+import domain.TransferService;
+import infra.SchemaBootstrap;
+import java.math.BigDecimal;
+import javax.sql.DataSource;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.context.annotation.Bean;
+
+/**
+ * STAGE 3 — @TransactionalEventListener(AFTER_COMMIT) 해결.
+ *
+ * STAGE 2 와 같은 시나리오, 다른 listener
+ *
+ * - (1) 정상 송금 — commit 성공 → listener 호출 ✓
+ * - (2) 실패 송금 — rollback → listener 호출 안 됨 ✓ (= STAGE 2 한계 해결)
+ *
+ *
+ * STAGE 2 vs STAGE 3 출력 비교
+ *
+ * STAGE 2 (동기 @EventListener):
+ * (1) 정상 [AUDIT] [NOTIFY] (commit 전, 동기)
+ * (2) 실패 [AUDIT] [NOTIFY] (commit 전, rollback 돼도 이미 호출) ✗
+ *
+ * STAGE 3 (@TransactionalEventListener(AFTER_COMMIT)):
+ * (1) 정상 [AUDIT-AC] [NOTIFY-AC] (commit 후 호출)
+ * (2) 실패 (listener 호출 X — 외부 호출 안전) ✓
+ *
+ *
+ * 실행
+ * ./gradlew run -PmainClass=stage.Stage3AfterCommit
+ */
+@SpringBootApplication(scanBasePackages = {"domain", "infra"})
+public class Stage3AfterCommit {
+
+ @Bean
+ public TransferAfterCommitListeners afterCommitListeners() {
+ return new TransferAfterCommitListeners();
+ }
+
+ public static void main(String[] args) throws Exception {
+ ConfigurableApplicationContext ctx = SpringApplication.run(Stage3AfterCommit.class, args);
+
+ DataSource ds = ctx.getBean(DataSource.class);
+ SchemaBootstrap.reset(ds);
+
+ TransferService svc = ctx.getBean(TransferService.class);
+
+ System.out.println();
+ System.out.println("=== STAGE 3 — @TransactionalEventListener(AFTER_COMMIT) 해결 ===");
+
+ System.out.println();
+ System.out.println("--- (1) 정상 송금 transfer(1 → 2, 100) ---");
+ svc.transfer(1L, 2L, new BigDecimal("100"));
+
+ System.out.println();
+ System.out.println("--- (2) 실패 송금 transferWithFailure(1 → 2, 50) — 일부러 예외 ---");
+ try {
+ svc.transferWithFailure(1L, 2L, new BigDecimal("50"));
+ } catch (RuntimeException e) {
+ System.out.println(" [caller] 예외 잡음: " + e.getMessage());
+ System.out.println(" ← listener (AC) 호출 안 됨 (commit 안 됐으므로)");
+ }
+
+ System.out.println();
+ System.out.println("--- balance / fee 확인 ---");
+ System.out.println(" id=1 잔액 = " + svc.balanceOf(1L) + " (예상: 999890, 정상 송금만 반영)");
+ System.out.println(" id=2 잔액 = " + svc.balanceOf(2L) + " (예상: 1000100)");
+ System.out.println(" fee 누적 = " + svc.feeTotal() + " (예상: 10)");
+
+ System.out.println();
+ System.out.println("[학습 포인트] — 5 주차 한계 해결");
+ System.out.println(" · 정상 commit → [AUDIT-AC] / [NOTIFY-AC] 호출 ✓");
+ System.out.println(" · rollback → listener 호출 X ✓ — 외부 호출 안전");
+ System.out.println(" · 변경점은 어노테이션 한 줄 (@EventListener → @TransactionalEventListener(AFTER_COMMIT))");
+ System.out.println(" · STAGE 2 의 같은 시나리오와 출력 직접 비교");
+
+ ctx.close();
+ }
+}
diff --git a/topics/06-event/members/chanhyeok/src/main/resources/application.properties b/topics/06-event/members/chanhyeok/src/main/resources/application.properties
new file mode 100644
index 0000000..fe5a749
--- /dev/null
+++ b/topics/06-event/members/chanhyeok/src/main/resources/application.properties
@@ -0,0 +1,9 @@
+# 3주차 docker-compose 그대로 — PostgreSQL + Redis
+spring.datasource.url=jdbc:postgresql://localhost:5433/csstudy
+spring.datasource.username=csstudy
+spring.datasource.password=csstudy1234
+spring.datasource.driver-class-name=org.postgresql.Driver
+spring.datasource.hikari.maximum-pool-size=50
+
+# Spring AOP 기본 = CGLIB (Spring Boot 2.0+)
+spring.aop.proxy-target-class=true