[JDBC 라이브러리 구현하기 - 4단계] 가비 미션 제출합니다.

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

@@ -1,6 +1,5 @@
 package com.techcourse.dao;
 
-import java.sql.Connection;
 import java.util.List;
 import java.util.Optional;
 
@@ -42,14 +41,6 @@ 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 = ?";
-
-        log.debug("query : {}", sql);
-
-        jdbcTemplate.update(connection, sql, user.getAccount(), user.getPassword(), user.getEmail(), user.getId());
-    }
-
     public Optional<User> findById(final Long id) {
         final String sql = "select id, account, password, email from users where id = ?";
 

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

@@ -1,7 +1,5 @@
 package com.techcourse.dao;
 
-import java.sql.Connection;
-
 import com.techcourse.domain.UserHistory;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -32,19 +30,4 @@ public void log(final UserHistory userHistory) {
         log.debug("query : {}", sql);
     }
 
-    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()
-        );
-
-        log.debug("query : {}", sql);
-    }
-
 }

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

@@ -0,0 +1,36 @@
+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).orElseThrow();
+    }
+
+    @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 +1,32 @@
+package com.techcourse.service;
+
+import com.techcourse.config.DataSourceConfig;
+import com.techcourse.domain.User;
+import org.springframework.transaction.TransactionManager;
+
+public class TxUserService implements UserService {
+
+    private final UserService userService;
+    private final TransactionManager transactionManager;
+
+    public TxUserService(final UserService userService) {
+        this.userService = userService;
+        this.transactionManager = new TransactionManager(DataSourceConfig.getInstance());
+    }
+
+    @Override
+    public User findById(final long id) {
+        return userService.findById(id);
+    }
+
+    @Override
+    public void insert(final User user) {
+        transactionManager.run(() -> userService.insert(user));
+    }
+
+    @Override
+    public void changePassword(final long id, final String newPassword, final String createBy) {
+        transactionManager.run(() -> userService.changePassword(id, newPassword, createBy));
+    }
+
+}

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

@@ -1,60 +1,13 @@
 package com.techcourse.service;
 
-import java.sql.Connection;
-import java.sql.SQLException;
-import java.util.Optional;
-
-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 org.springframework.dao.DataAccessException;
-
-public class UserService {
-
-    private final UserDao userDao;
-    private final UserHistoryDao userHistoryDao;
-
-    public UserService(final UserDao userDao, final UserHistoryDao userHistoryDao) {
-        this.userDao = userDao;
-        this.userHistoryDao = userHistoryDao;
-    }
-
-    public Optional<User> findById(final long id) {
-        return userDao.findById(id);
-    }
 
-    public void insert(final User user) {
-        userDao.insert(user);
-    }
+public interface UserService {
 
-    public void changePassword(final long id, final String newPassword, final String createBy) {
-        Connection connection = null;
-        try {
-            connection = DataSourceConfig.getInstance().getConnection();
-            connection.setAutoCommit(false);
+    User findById(final long id);
 
-            final User user = findById(id).orElseThrow();
-            user.changePassword(newPassword);
-            userDao.update(connection, user);
-            userHistoryDao.log(connection, new UserHistory(user, createBy));
+    void insert(final User user);
 
-            connection.commit();
-        } catch (final SQLException e) {
-            try {
-                connection.rollback();
-            } catch (final SQLException rollbackException) {
-                throw new DataAccessException(rollbackException);
-            }
-            throw new DataAccessException(e);
-        } finally {
-            try {
-                connection.close();
-            } catch (final SQLException e) {
-                throw new DataAccessException(e);
-            }
-        }
-    }
+    void changePassword(final long id, final String newPassword, final String createBy);
 
 }

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

@@ -14,7 +14,7 @@ public MockUserHistoryDao(final JdbcTemplate jdbcTemplate) {
     }
 
     @Override
-    public void log(final Connection connection, final UserHistory userHistory) {
+    public void log(final UserHistory userHistory) {
         throw new DataAccessException();
     }
 

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

@@ -31,31 +31,35 @@ void setUp() {
     @Test
     void testChangePassword() {
         final UserHistoryDao userHistoryDao = new UserHistoryDao(jdbcTemplate);
-        final UserService userService = new UserService(userDao, userHistoryDao);
+        final UserService userService = new AppUserService(userDao, userHistoryDao);
 
         final String newPassword = "qqqqq";
         final String createBy = "gugu";
         userService.changePassword(1L, newPassword, createBy);
 
-        final User actual = userService.findById(1L).orElseThrow();
+        final User actual = userService.findById(1L);
 
         assertThat(actual.getPassword()).isEqualTo(newPassword);
     }
 
     @Test
     void testTransactionRollback() {
         // 트랜잭션 롤백 테스트를 위해 mock으로 교체
-        final UserHistoryDao userHistoryDao = new MockUserHistoryDao(jdbcTemplate);
-        final UserService userService = new UserService(userDao, userHistoryDao);
+        final var userHistoryDao = new MockUserHistoryDao(jdbcTemplate);
+        // 애플리케이션 서비스
+        final UserService appUserService = new AppUserService(userDao, userHistoryDao);
+        // 트랜잭션 서비스 추상화
+        final UserService txUserService = new TxUserService(appUserService);
 
-        final String newPassword = "newPassword";
-        final String createBy = "gugu";
+        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 User actual = userService.findById(1L).orElseThrow();
+        final var actual = txUserService.findById(1L);
 
         assertThat(actual.getPassword()).isNotEqualTo(newPassword);
     }
+
 }

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

@@ -12,6 +12,7 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.dao.DataAccessException;
+import org.springframework.jdbc.datasource.DataSourceUtils;
 
 public class JdbcTemplate {
 
@@ -23,26 +24,6 @@ public JdbcTemplate(final DataSource dataSource) {
         this.dataSource = dataSource;
     }
 
-    public void update(final Connection connection, final String sql, final Object... elements) {
-        execute(connection, sql, PreparedStatement::executeUpdate, elements);
-    }
-
-    private <T> T execute(
-            final Connection connection,
-            final String sql,
-            final PreparedStatementExecutor<T> executor,
-            final Object... elements
-    ) {
-        try (final PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
-            setElements(elements, preparedStatement);
-
-            return executor.action(preparedStatement);
-        } catch (final SQLException e) {
-            log.error(e.getMessage(), e);
-            throw new DataAccessException(e);
-        }
-    }
-
     public void update(final String sql, final Object... elements) {
         execute(sql, PreparedStatement::executeUpdate, elements);
     }
@@ -52,9 +33,8 @@ private <T> T execute(
             final PreparedStatementExecutor<T> executor,
             final Object... elements
     ) {
-        try (final Connection connection = dataSource.getConnection();
-             final PreparedStatement preparedStatement = connection.prepareStatement(sql)
-        ) {
+        final Connection connection = DataSourceUtils.getConnection(dataSource);
+        try  (final PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
             setElements(elements, preparedStatement);
 
             return executor.action(preparedStatement);

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

@@ -29,6 +29,7 @@ public static Connection getConnection(DataSource dataSource) throws CannotGetJd
 
     public static void releaseConnection(Connection connection, DataSource dataSource) {
         try {
+            TransactionSynchronizationManager.unbindResource(dataSource);
             connection.close();
         } catch (SQLException ex) {
             throw new CannotGetJdbcConnectionException("Failed to close JDBC Connection");

jdbc/src/main/java/org/springframework/transaction/TransactionManager.java

@@ -0,0 +1,43 @@
+package org.springframework.transaction;
+
+import java.sql.Connection;
+import java.sql.SQLException;
+
+import javax.sql.DataSource;
+import org.springframework.dao.DataAccessException;
+import org.springframework.jdbc.datasource.DataSourceUtils;
+import org.springframework.transaction.support.TransactionExecutor;
+
+public class TransactionManager {
+
+    private final DataSource dataSource;
+
+    public TransactionManager(final DataSource dataSource) {
+        this.dataSource = dataSource;
+    }
+
+    public void run(final TransactionExecutor transactionExecutor) {
+        final Connection connection = DataSourceUtils.getConnection(dataSource);
+        try {
+            connection.setAutoCommit(false);
+
+            transactionExecutor.action();
+
+            connection.commit();
+        } catch (final SQLException e) {
+            rollBackConnection(connection);
+            throw new DataAccessException(e);
+        } finally {
+            DataSourceUtils.releaseConnection(connection, dataSource);
+        }
+    }
+
+    private static void rollBackConnection(final Connection connection) {
+        try {
+            connection.rollback();
+        } catch (final SQLException e) {
+            throw new DataAccessException(e);
+        }
+    }
+
+}

jdbc/src/main/java/org/springframework/transaction/support/TransactionExecutor.java

@@ -0,0 +1,8 @@
+package org.springframework.transaction.support;
+
+@FunctionalInterface
+public interface TransactionExecutor {
+
+    void action();
+
+}

jdbc/src/main/java/org/springframework/transaction/support/TransactionSynchronizationManager.java

@@ -2,22 +2,30 @@
 
 import javax.sql.DataSource;
 import java.sql.Connection;
+import java.util.HashMap;
 import java.util.Map;
 
 public abstract class TransactionSynchronizationManager {
 
-    private static final ThreadLocal<Map<DataSource, Connection>> resources = new ThreadLocal<>();
+    private static final ThreadLocal<Map<DataSource, Connection>> resources = ThreadLocal.withInitial(() -> new HashMap<>());
 
-    private TransactionSynchronizationManager() {}
+    private TransactionSynchronizationManager() {
+    }
 
     public static Connection getResource(DataSource key) {
-        return null;
+        return getResources().get(key);
     }
 
     public static void bindResource(DataSource key, Connection value) {
+        getResources().put(key, value);
+    }
+
+    public static void unbindResource(DataSource key) {
+        getResources().remove(key);
     }
 
-    public static Connection unbindResource(DataSource key) {
-        return null;
+    private static Map<DataSource, Connection> getResources() {
+        return resources.get();
     }
+
 }

jdbc/src/test/java/nextstep/jdbc/JdbcTemplateTest.java

@@ -90,7 +90,7 @@ class queryForObject는 {
 
 
         @Test
-        void 결과가_존재하지_않으면_Optional을_반환한다() throws Exception {
+        void 결과가_존재하지_않으면_Optional_empty를_반환한다() throws Exception {
             // given
             when(resultSet.next()).thenReturn(false);
             final String sql = "select * from users where id = ?";