[JDBC 라이브러리 구현하기 - 4단계] 이리내(성채연) 미션 제출합니다. (#588)

이리내 안녕하세요~! 학습테스트까지 모두 하시느라 고생 많으셨습니다. 저의 지식을 총동원해서 리뷰를 남겼었는데 모두 적용해주셨네요 ..감동받았구요.. 
이리내의 답변을 보고 저도 힌트를 많이 얻어갈 수 있었네요!
이만 머지하도록 하겠습니다~!

app/src/main/java/com/techcourse/dao/UserDao.java

@@ -37,11 +37,6 @@ public void update(final User user) {
         jdbcTemplate.update(sql, user.getAccount(), user.getPassword(), user.getEmail(), user.getId());
     }
 
-    public void update(final Connection connection, final User user) {
-        final String sql = "update users set account = ?, password = ?, email = ? where id = ?";
-        jdbcTemplate.update(connection, sql, user.getAccount(), user.getPassword(), user.getEmail(), user.getId());
-    }
-
     public List<User> findAll() {
         final String sql = "select id, account, password, email from users";
         return jdbcTemplate.queryForList(sql, ROW_MAPPER);

app/src/main/java/com/techcourse/dao/UserHistoryDao.java

@@ -30,19 +30,4 @@ public void log(final UserHistory userHistory) {
                 userHistory.getCreateBy()
         );
     }
-
-    public void log(final Connection connection, final UserHistory userHistory) {
-        final var sql = "insert into user_history (user_id, account, password, email, created_at, created_by) values (?, ?, ?, ?, ?, ?)";
-
-        jdbcTemplate.update(
-                connection,
-                sql,
-                userHistory.getUserId(),
-                userHistory.getAccount(),
-                userHistory.getPassword(),
-                userHistory.getEmail(),
-                userHistory.getCreatedAt(),
-                userHistory.getCreateBy()
-        );
-    }
 }

app/src/main/java/com/techcourse/service/AppUserService.java

@@ -0,0 +1,35 @@
+package com.techcourse.service;
+
+import com.techcourse.dao.UserDao;
+import com.techcourse.dao.UserHistoryDao;
+import com.techcourse.domain.User;
+import com.techcourse.domain.UserHistory;
+
+public class AppUserService implements UserService {
+
+    private final UserDao userDao;
+    private final UserHistoryDao userHistoryDao;
+
+    public AppUserService(final UserDao userDao, final UserHistoryDao userHistoryDao) {
+        this.userDao = userDao;
+        this.userHistoryDao = userHistoryDao;
+    }
+
+    @Override
+    public User findById(final long id) {
+        return userDao.findById(id);
+    }
+
+    @Override
+    public void insert(final User user) {
+        userDao.insert(user);
+    }
+
+    @Override
+    public void changePassword(final long id, final String newPassword, final String createBy) {
+        final User user = findById(id);
+        user.changePassword(newPassword);
+        userDao.update(user);
+        userHistoryDao.log(new UserHistory(user, createBy));
+    }
+}

app/src/main/java/com/techcourse/service/TxUserService.java

@@ -0,0 +1,30 @@
+package com.techcourse.service;
+
+import com.techcourse.domain.User;
+import org.springframework.transaction.TransactionExecutor;
+
+public class TxUserService implements UserService {
+
+    private final UserService userService;
+    private final TransactionExecutor transactionExecutor;
+
+    public TxUserService(final UserService userService, final TransactionExecutor transactionExecutor) {
+        this.userService = userService;
+        this.transactionExecutor = transactionExecutor;
+    }
+
+    @Override
+    public User findById(final long id) {
+        return transactionExecutor.execute(() -> userService.findById(id));
+    }
+
+    @Override
+    public void insert(final User user) {
+        transactionExecutor.execute(() -> userService.insert(user));
+    }
+
+    @Override
+    public void changePassword(final long id, final String newPassword, final String createBy) {
+        transactionExecutor.execute(() -> userService.changePassword(id, newPassword, createBy));
+    }
+}

app/src/main/java/com/techcourse/service/UserService.java

@@ -1,64 +1,10 @@
 package com.techcourse.service;
 
-import com.techcourse.config.DataSourceConfig;
-import com.techcourse.dao.UserDao;
-import com.techcourse.dao.UserHistoryDao;
 import com.techcourse.domain.User;
-import com.techcourse.domain.UserHistory;
-import java.sql.Connection;
-import java.sql.SQLException;
-import javax.sql.DataSource;
-import org.springframework.dao.DataAccessException;
 
-public class UserService {
+public interface UserService {
 
-    private final UserDao userDao;
-    private final UserHistoryDao userHistoryDao;
-
-    public UserService(final UserDao userDao, final UserHistoryDao userHistoryDao) {
-        this.userDao = userDao;
-        this.userHistoryDao = userHistoryDao;
-    }
-
-    public User findById(final long id) {
-        return userDao.findById(id);
-    }
-
-    public void insert(final User user) {
-        userDao.insert(user);
-    }
-
-    public void changePassword(final long id, final String newPassword, final String createBy)  {
-        final DataSource dataSource = DataSourceConfig.getInstance();
-        final Connection connection = getConnection(dataSource);
-        try (connection) {
-            connection.setAutoCommit(false);
-
-            final User user = findById(id);
-            user.changePassword(newPassword);
-            userDao.update(connection, user);
-            userHistoryDao.log(connection, new UserHistory(user, createBy));
-
-            connection.commit();
-        } catch (SQLException | DataAccessException e) {
-            rollback(connection);
-            throw new DataAccessException(e);
-        }
-    }
-
-    private Connection getConnection(final DataSource dataSource) {
-        try {
-            return dataSource.getConnection();
-        } catch (SQLException e) {
-            throw new DataAccessException();
-        }
-    }
-
-    private void rollback(final Connection connection) {
-        try {
-            connection.rollback();
-        } catch (SQLException e) {
-            throw new DataAccessException();
-        }
-    }
+    User findById(final long id);
+    void insert(final User user);
+    void changePassword(final long id, final String newPassword, final String createBy);
 }

app/src/test/java/com/techcourse/service/MockUserHistoryDao.java

@@ -16,9 +16,4 @@ public MockUserHistoryDao(final JdbcTemplate jdbcTemplate) {
     public void log(final UserHistory userHistory) {
         throw new DataAccessException();
     }
-
-    @Override
-    public void log(final Connection connection, final UserHistory userHistory) {
-        throw new DataAccessException();
-    }
 }

app/src/test/java/com/techcourse/service/UserServiceTest.java

@@ -8,8 +8,8 @@
 import org.springframework.dao.DataAccessException;
 import org.springframework.jdbc.core.JdbcTemplate;
 import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
+import org.springframework.transaction.TransactionExecutor;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.jupiter.api.Assertions.assertThrows;
@@ -31,31 +31,35 @@ void setUp() {
 
     @Test
     void testChangePassword() {
-        final var userHistoryDao = new UserHistoryDao(jdbcTemplate);
-        final var userService = new UserService(userDao, userHistoryDao);
+        final UserHistoryDao userHistoryDao = new UserHistoryDao(jdbcTemplate);
+        final AppUserService appUserService = new AppUserService(userDao, userHistoryDao);
+        final TxUserService txUserService = new TxUserService(appUserService, new TransactionExecutor(DataSourceConfig.getInstance()));
 
         final var newPassword = "qqqqq";
         final var createBy = "gugu";
-        userService.changePassword(1L, newPassword, createBy);
+        txUserService.changePassword(1L, newPassword, createBy);
 
-        final var actual = userService.findById(1L);
+        final var actual = txUserService.findById(1L);
 
         assertThat(actual.getPassword()).isEqualTo(newPassword);
     }
 
     @Test
     void testTransactionRollback() {
         // 트랜잭션 롤백 테스트를 위해 mock으로 교체
-        final var userHistoryDao = new MockUserHistoryDao(jdbcTemplate);
-        final var userService = new UserService(userDao, userHistoryDao);
+        final MockUserHistoryDao userHistoryDao = new MockUserHistoryDao(jdbcTemplate);
+        // 애플리케이션 서비스
+        final AppUserService appUserService = new AppUserService(userDao, userHistoryDao);
+        // 트랜잭션 서비스 추상화
+        final TxUserService txUserService = new TxUserService(appUserService, new TransactionExecutor(DataSourceConfig.getInstance()));
 
         final var newPassword = "newPassword";
         final var createBy = "gugu";
         // 트랜잭션이 정상 동작하는지 확인하기 위해 의도적으로 MockUserHistoryDao에서 예외를 발생시킨다.
         assertThrows(DataAccessException.class,
-                () -> userService.changePassword(1L, newPassword, createBy));
+                () -> txUserService.changePassword(1L, newPassword, createBy));
 
-        final var actual = userService.findById(1L);
+        final var actual = txUserService.findById(1L);
 
         assertThat(actual.getPassword()).isNotEqualTo(newPassword);
     }

jdbc/build.gradle

@@ -15,6 +15,7 @@ dependencies {
     implementation "org.apache.commons:commons-lang3:3.13.0"
     implementation "ch.qos.logback:logback-classic:1.2.12"
 
+    testImplementation "com.h2database:h2:2.2.220"
     testImplementation "org.assertj:assertj-core:3.24.2"
     testImplementation "org.junit.jupiter:junit-jupiter-api:5.7.2"
     testImplementation "org.mockito:mockito-core:5.4.0"

jdbc/src/main/java/org/springframework/jdbc/ConnectionHolder.java

@@ -0,0 +1,31 @@
+package org.springframework.jdbc;
+
+import static java.util.Objects.isNull;
+
+import java.sql.Connection;
+
+public class ConnectionHolder {
+
+    private Connection connection;
+    private boolean transactionActive = false;
+
+    public ConnectionHolder(final Connection connection) {
+        this.connection = connection;
+    }
+
+    public void setTransactionActive(final boolean transactionActive) {
+        this.transactionActive = transactionActive;
+    }
+
+    public boolean isTransactionActive() {
+        return transactionActive;
+    }
+
+    public Connection getConnection() {
+        return connection;
+    }
+
+    public boolean has(final Connection connection) {
+        return this.connection == connection;
+    }
+}

jdbc/src/main/java/org/springframework/jdbc/core/JdbcTemplate.java

@@ -8,6 +8,7 @@
 import java.util.List;
 import javax.sql.DataSource;
 import org.springframework.dao.DataAccessException;
+import org.springframework.jdbc.datasource.DataSourceUtils;
 
 public class JdbcTemplate {
 
@@ -23,24 +24,13 @@ public int update(final String sql, final Object... args) {
 
     private <T> T execute(final PreparedStatementCallback preparedStatementCallback,
                           final ExecutionCallback<T> executionCallback) {
-        try (final Connection connection = dataSource.getConnection()) {
-            return executeWithConnection(connection, preparedStatementCallback, executionCallback);
-        } catch (SQLException e) {
-            throw new DataAccessException(e);
-        }
-    }
-
-    public int update(final Connection connection, final String sql, final Object... args) {
-        return executeWithConnection(connection, conn -> prepareStatement(sql, conn, args), PreparedStatement::executeUpdate);
-    }
-
-    private <T> T executeWithConnection(final Connection connection,
-                                        final PreparedStatementCallback preparedStatementCallback,
-                                        final ExecutionCallback<T> executionCallback) {
+        final Connection connection = DataSourceUtils.getConnection(dataSource);
         try (final PreparedStatement pstmt = preparedStatementCallback.prepareStatement(connection)) {
             return executionCallback.execute(pstmt);
         } catch (SQLException e) {
             throw new DataAccessException(e);
+        } finally {
+            DataSourceUtils.releaseConnection(connection, dataSource);
         }
     }
 

jdbc/src/main/java/org/springframework/jdbc/datasource/DataSourceUtils.java

@@ -1,6 +1,10 @@
 package org.springframework.jdbc.datasource;
 
+import static java.util.Objects.isNull;
+
+import org.springframework.dao.DataAccessException;
 import org.springframework.jdbc.CannotGetJdbcConnectionException;
+import org.springframework.jdbc.ConnectionHolder;
 import org.springframework.transaction.support.TransactionSynchronizationManager;
 
 import javax.sql.DataSource;
@@ -12,23 +16,59 @@ public abstract class DataSourceUtils {
 
     private DataSourceUtils() {}
 
-    public static Connection getConnection(DataSource dataSource) throws CannotGetJdbcConnectionException {
-        Connection connection = TransactionSynchronizationManager.getResource(dataSource);
-        if (connection != null) {
-            return connection;
+    public static Connection getConnection(final DataSource dataSource) throws CannotGetJdbcConnectionException {
+        final ConnectionHolder connectionHolder = TransactionSynchronizationManager.getResource(dataSource);
+        if (connectionHolder != null) {
+            return connectionHolder.getConnection();
         }
 
         try {
-            connection = dataSource.getConnection();
+            final Connection connection = dataSource.getConnection();
             TransactionSynchronizationManager.bindResource(dataSource, connection);
             return connection;
         } catch (SQLException ex) {
             throw new CannotGetJdbcConnectionException("Failed to obtain JDBC Connection", ex);
         }
     }
 
-    public static void releaseConnection(Connection connection, DataSource dataSource) {
+    public static void startTransaction(final Connection connection, final DataSource dataSource) {
+        final ConnectionHolder connectionHolder = getConnectionHolder(connection, dataSource);
+        try{
+            connectionHolder.setTransactionActive(true);
+            connection.setAutoCommit(false);
+        }catch(SQLException e) {
+            throw new DataAccessException();
+        }
+    }
+
+    private static ConnectionHolder getConnectionHolder(final Connection connection, final DataSource dataSource) {
+        final ConnectionHolder connectionHolder = TransactionSynchronizationManager.getResource(dataSource);
+        if(isNull(connectionHolder)) {
+            throw new IllegalStateException();
+        }
+        if(!connectionHolder.has(connection)) {
+            throw new IllegalStateException();
+        }
+        return connectionHolder;
+    }
+
+    public static void finishTransaction(final Connection connection, final DataSource dataSource) {
+        final ConnectionHolder connectionHolder = getConnectionHolder(connection, dataSource);
+        try{
+            connection.commit();
+            connectionHolder.setTransactionActive(false);
+        }catch(SQLException e) {
+            throw new DataAccessException();
+        }
+    }
+
+    public static void releaseConnection(final Connection connection, final DataSource dataSource) {
         try {
+            final ConnectionHolder connectionHolder = getConnectionHolder(connection, dataSource);
+            if(connectionHolder.isTransactionActive()) {
+                return;
+            }
+            TransactionSynchronizationManager.unbindResource(dataSource);
             connection.close();
         } catch (SQLException ex) {
             throw new CannotGetJdbcConnectionException("Failed to close JDBC Connection");