diff --git a/src/main/java/com/github/sttk/sabi/DataHub.java b/src/main/java/com/github/sttk/sabi/DataHub.java
index e9a2ee8..981179b 100644
--- a/src/main/java/com/github/sttk/sabi/DataHub.java
+++ b/src/main/java/com/github/sttk/sabi/DataHub.java
@@ -88,14 +88,6 @@ public record CreatedDataConnIsNull(String name, String dataConnType) {}
    */
   public record FailToCastDataConn(String name, String castToType) {}
 
-  /**
-   * Represents an error reason that occurred when failing to cast the {@code DataHub} instance
-   * itself to the expected data access interface type for a {@link Logic}.
-   *
-   * @param castFromType The actual type of the {@code DataHub} instance that failed to cast.
-   */
-  public record FailToCastDataHub(String castFromType) {}
-
   /**
    * Represents an unexpected {@link RuntimeException} that occurred during pre-commit or commit
    * operations.
@@ -128,71 +120,6 @@ public void disuses(String name) {
     inner.disuses(name);
   }
 
-  /**
-   * Executes the provided application {@link Logic} without transactional boundaries. The {@code
-   * DataHub} instance itself is passed as the data access object {@code D} to the {@link Logic}'s
-   * {@code run} method.
-   *
-   * @param <D> The type of the data access object, which typically is {@code DataHub} or an
-   *     interface implemented by {@code DataHub} that {@link Logic} expects.
-   * @param logic The application logic to execute.
-   * @throws Exc if an {@link Exc} or {@link RuntimeException} occurs during logic execution or if
-   *     the {@code DataHub} cannot be cast to the expected data access type.
-   */
-  public <D> void run(Logic<D> logic) throws Exc {
-    D data;
-    try {
-      @SuppressWarnings("unchecked")
-      D d = (D) this;
-      data = d;
-    } catch (Exception e) {
-      throw new Exc(new FailToCastDataHub(this.getClass().getName()));
-    }
-    try {
-      inner.begin();
-      logic.run(data);
-    } catch (Exc | RuntimeException e) {
-      throw e;
-    } finally {
-      inner.end();
-    }
-  }
-
-  /**
-   * Executes the provided application {@link Logic} within a transactional context. The {@code
-   * DataHub} instance is passed as the data access object {@code D} to the {@link Logic}'s {@code
-   * run} method. If the logic completes successfully, a commit operation is attempted. If any
-   * {@link Exc}, {@link RuntimeException}, or {@link Error} occurs, a rollback operation is
-   * performed.
-   *
-   * @param <D> The type of the data access object, which typically is {@code DataHub} or an
-   *     interface implemented by {@code DataHub} that {@link Logic} expects.
-   * @param logic The application logic to execute transactionally.
-   * @throws Exc if an {@link Exc}, {@link RuntimeException}, or {@link Error} occurs during logic
-   *     execution, pre-commit, or commit. The original exception is re-thrown after rollback.
-   */
-  public <D> void txn(Logic<D> logic) throws Exc {
-    D data;
-    try {
-      @SuppressWarnings("unchecked")
-      D d = (D) this;
-      data = d;
-    } catch (Exception e) {
-      throw new Exc(new FailToCastDataHub(this.getClass().getName()));
-    }
-    try {
-      inner.begin();
-      logic.run(data);
-      inner.commit();
-      inner.postCommit();
-    } catch (Exc | RuntimeException | Error e) {
-      inner.rollback();
-      throw e;
-    } finally {
-      inner.end();
-    }
-  }
-
   /**
    * Retrieves a {@link DataConn} instance from the managed data sources. This method is part of the
    * {@link DataAcc} interface implementation.
@@ -218,4 +145,20 @@ public <C extends DataConn> C getDataConn(String name, Class<C> cls) throws Exc
   public void close() {
     inner.close();
   }
+
+  void begin() throws Exc {
+    inner.begin();
+  }
+
+  void commit() throws Exc {
+    inner.commit();
+  }
+
+  void rollback() {
+    inner.rollback();
+  }
+
+  void end() {
+    inner.end();
+  }
 }
diff --git a/src/main/java/com/github/sttk/sabi/Sabi.java b/src/main/java/com/github/sttk/sabi/Sabi.java
index 6a4c2fc..022c042 100644
--- a/src/main/java/com/github/sttk/sabi/Sabi.java
+++ b/src/main/java/com/github/sttk/sabi/Sabi.java
@@ -34,6 +34,14 @@
  *   }</code></pre>
  */
 public final class Sabi {
+  /**
+   * Represents an error reason that occurred when failing to cast the {@code DataHub} instance
+   * itself to the expected data access interface type for a {@link Logic}.
+   *
+   * @param castFromType The actual type of the {@code DataHub} instance that failed to cast.
+   */
+  public record FailToCastDataHub(String castFromType) {}
+
   private Sabi() {}
 
   /**
@@ -63,4 +71,72 @@ public static void uses(String name, DataSrc ds) {
   public static AutoCloseable setup() throws Exc {
     return DataHubInner.setupGlobals();
   }
+
+  /**
+   * Executes the provided application {@link Logic} without transactional boundaries. The {@code
+   * DataHub} instance in the parameters is passed as the data access object {@code D} to the {@link
+   * Logic}'s {@code run} method.
+   *
+   * @param <D> The type of the data access object, which typically is {@code DataHub} or an
+   *     interface implemented by {@code DataHub} that {@link Logic} expects.
+   * @param logic The application logic to execute.
+   * @param hub An instance of a DataHub subclass that inherits the data interface for logic
+   *     arguments.
+   * @throws Exc if an {@link Exc} or {@link RuntimeException} occurs during logic execution or if
+   *     the {@code DataHub} cannot be cast to the expected data access type.
+   */
+  public static <D> void run(Logic<D> logic, DataHub hub) throws Exc {
+    D data;
+    try {
+      @SuppressWarnings("unchecked")
+      D d = (D) hub;
+      data = d;
+    } catch (Exception e) {
+      throw new Exc(new FailToCastDataHub(hub.getClass().getName()));
+    }
+    try {
+      hub.begin();
+      logic.run(data);
+    } catch (Exc | RuntimeException e) {
+      throw e;
+    } finally {
+      hub.end();
+    }
+  }
+
+  /**
+   * Executes the provided application {@link Logic} within a transactional context. The {@code
+   * DataHub} instance in the parameter is passed as the data access object {@code D} to the {@link
+   * Logic}'s {@code run} method. If the logic completes successfully, a commit operation is
+   * attempted. If any {@link Exc}, {@link RuntimeException}, or {@link Error} occurs, a rollback
+   * operation is performed.
+   *
+   * @param <D> The type of the data access object, which typically is {@code DataHub} or an
+   *     interface implemented by {@code DataHub} that {@link Logic} expects.
+   * @param logic The application logic to execute transactionally.
+   * @param hub An instance of a DataHub subclass that inherits the data interface for logic
+   *     arguments.
+   * @throws Exc if an {@link Exc}, {@link RuntimeException}, or {@link Error} occurs during logic
+   *     execution, pre-commit, or commit. The original exception is re-thrown after rollback.
+   */
+  public static <D> void txn(Logic<D> logic, DataHub hub) throws Exc {
+    D data;
+    try {
+      @SuppressWarnings("unchecked")
+      D d = (D) hub;
+      data = d;
+    } catch (Exception e) {
+      throw new Exc(new FailToCastDataHub(hub.getClass().getName()));
+    }
+    try {
+      hub.begin();
+      logic.run(data);
+      hub.commit();
+    } catch (Exc | RuntimeException | Error e) {
+      hub.rollback();
+      throw e;
+    } finally {
+      hub.end();
+    }
+  }
 }
diff --git a/src/main/java/com/github/sttk/sabi/internal/DataHubInner.java b/src/main/java/com/github/sttk/sabi/internal/DataHubInner.java
index e29f1f3..369a533 100644
--- a/src/main/java/com/github/sttk/sabi/internal/DataHubInner.java
+++ b/src/main/java/com/github/sttk/sabi/internal/DataHubInner.java
@@ -138,30 +138,28 @@ public void commit() throws Exc {
     if (!excMap.isEmpty()) {
       throw new Exc(new DataHub.FailToCommitDataConn(excMap));
     }
-  }
 
-  public void rollback() {
-    var ag = new AsyncGroupImpl();
-    var ptr = this.dataConnList.head;
+    ag = new AsyncGroupImpl();
+    ptr = this.dataConnList.head;
     while (ptr != null) {
       ag.name = ptr.name;
-      if (ptr.conn.shouldForceBack()) {
-        ptr.conn.forceBack(ag);
-      } else {
-        ptr.conn.rollback(ag);
-      }
+      ptr.conn.postCommit(ag);
       ptr = ptr.next;
     }
 
     ag.joinAndIgnoreExcs();
   }
 
-  public void postCommit() {
+  public void rollback() {
     var ag = new AsyncGroupImpl();
     var ptr = this.dataConnList.head;
     while (ptr != null) {
       ag.name = ptr.name;
-      ptr.conn.postCommit(ag);
+      if (ptr.conn.shouldForceBack()) {
+        ptr.conn.forceBack(ag);
+      } else {
+        ptr.conn.rollback(ag);
+      }
       ptr = ptr.next;
     }
 
diff --git a/src/test/java/com/github/sttk/sabi/internal/DataAccTest.java b/src/test/java/com/github/sttk/sabi/internal/DataAccTest.java
index 97cef1b..91ee6ff 100644
--- a/src/test/java/com/github/sttk/sabi/internal/DataAccTest.java
+++ b/src/test/java/com/github/sttk/sabi/internal/DataAccTest.java
@@ -316,8 +316,8 @@ void test() {
 
       try (var ac = Sabi.setup()) {
         suppressWarnings_unused(ac);
-        try (var hub = new SampleDataHub()) {
-          hub.run(new SampleLogic());
+        try (var data = new SampleDataHub()) {
+          Sabi.run(new SampleLogic(), data);
         } catch (Exception e) {
           fail(e);
         }
@@ -358,11 +358,11 @@ void test() {
 
       try (var ac = Sabi.setup()) {
         suppressWarnings_unused(ac);
-        try (var hub = new SampleDataHub()) {
-          hub.uses("foo", new FooDataSrc(1, "hello", logger, false));
-          hub.uses("bar", new BarDataSrc(2, logger, false));
+        try (var data = new SampleDataHub()) {
+          data.uses("foo", new FooDataSrc(1, "hello", logger, false));
+          data.uses("bar", new BarDataSrc(2, logger, false));
 
-          hub.run(new SampleLogic());
+          Sabi.run(new SampleLogic(), data);
         } catch (Exception e) {
           fail(e);
         }
@@ -390,11 +390,11 @@ void test_not_run_logic_if_fail_to_setup_local_data_src() {
 
       try (var ac = Sabi.setup()) {
         suppressWarnings_unused(ac);
-        try (var hub = new SampleDataHub()) {
-          hub.uses("foo", new FooDataSrc(1, "hello", logger, true));
-          hub.uses("bar", new BarDataSrc(2, logger, false));
+        try (var data = new SampleDataHub()) {
+          data.uses("foo", new FooDataSrc(1, "hello", logger, true));
+          data.uses("bar", new BarDataSrc(2, logger, false));
 
-          hub.run(new SampleLogic());
+          Sabi.run(new SampleLogic(), data);
         } catch (Exc e) {
           switch (e.getReason()) {
             case DataHub.FailToSetupLocalDataSrcs r -> {
@@ -434,10 +434,10 @@ void test() {
 
       try (var ac = Sabi.setup()) {
         suppressWarnings_unused(ac);
-        try (var hub = new SampleDataHub()) {
-          hub.uses("foo", new FooDataSrc(2, "Hello", logger, false));
+        try (var data = new SampleDataHub()) {
+          data.uses("foo", new FooDataSrc(2, "Hello", logger, false));
 
-          hub.run(new SampleLogic());
+          Sabi.run(new SampleLogic(), data);
         } catch (Exception e) {
           fail(e);
         }
@@ -481,8 +481,8 @@ void test() {
 
       try (var ac = Sabi.setup()) {
         suppressWarnings_unused(ac);
-        try (var hub = new SampleDataHub()) {
-          hub.txn(new SampleLogic());
+        try (var data = new SampleDataHub()) {
+          Sabi.txn(new SampleLogic(), data);
         } catch (Exception e) {
           fail(e);
         }
@@ -529,11 +529,11 @@ void test() {
 
       try (var ac = Sabi.setup()) {
         suppressWarnings_unused(ac);
-        try (var hub = new SampleDataHub()) {
-          hub.uses("foo", new FooDataSrc(1, "Hello", logger, false));
-          hub.uses("bar", new BarDataSrc(2, logger, false));
+        try (var data = new SampleDataHub()) {
+          data.uses("foo", new FooDataSrc(1, "Hello", logger, false));
+          data.uses("bar", new BarDataSrc(2, logger, false));
 
-          hub.txn(new SampleLogic());
+          Sabi.txn(new SampleLogic(), data);
         } catch (Exception e) {
           fail(e);
         }
@@ -567,11 +567,11 @@ void test_not_run_logic_if_fail_to_setup_local_data_src() {
 
       try (var ac = Sabi.setup()) {
         suppressWarnings_unused(ac);
-        try (var hub = new SampleDataHub()) {
-          hub.uses("foo", new FooDataSrc(1, "Hello", logger, true));
-          hub.uses("bar", new BarDataSrc(2, logger, false));
+        try (var data = new SampleDataHub()) {
+          data.uses("foo", new FooDataSrc(1, "Hello", logger, true));
+          data.uses("bar", new BarDataSrc(2, logger, false));
 
-          hub.txn(new SampleLogic());
+          Sabi.txn(new SampleLogic(), data);
         } catch (Exc e) {
           switch (e.getReason()) {
             case DataHub.FailToSetupLocalDataSrcs r -> {
@@ -596,11 +596,11 @@ void test_not_run_logic_in_txn_and_rollback() {
 
       try (var ac = Sabi.setup()) {
         suppressWarnings_unused(ac);
-        try (var hub = new SampleDataHub()) {
-          hub.uses("foo", new FooDataSrc(1, "Hello", logger, false));
-          hub.uses("bar", new BarDataSrc(2, logger, false));
+        try (var data = new SampleDataHub()) {
+          data.uses("foo", new FooDataSrc(1, "Hello", logger, false));
+          data.uses("bar", new BarDataSrc(2, logger, false));
 
-          hub.txn(new FailingLogic());
+          Sabi.txn(new FailingLogic(), data);
         } catch (Exc e) {
           assertThat(e.getReason()).isEqualTo("ZZZ");
         } catch (Exception e) {
@@ -640,10 +640,10 @@ void test() {
 
       try (var ac = Sabi.setup()) {
         suppressWarnings_unused(ac);
-        try (var hub = new SampleDataHub()) {
-          hub.uses("foo", new FooDataSrc(2, "Hello", logger, false));
+        try (var data = new SampleDataHub()) {
+          data.uses("foo", new FooDataSrc(2, "Hello", logger, false));
 
-          hub.txn(new SampleLogic());
+          Sabi.txn(new SampleLogic(), data);
         } catch (Exception e) {
           fail(e);
         }
diff --git a/src/test/java/com/github/sttk/sabi/internal/DataHubInnerTest.java b/src/test/java/com/github/sttk/sabi/internal/DataHubInnerTest.java
index a85dc09..acc8aa9 100644
--- a/src/test/java/com/github/sttk/sabi/internal/DataHubInnerTest.java
+++ b/src/test/java/com/github/sttk/sabi/internal/DataHubInnerTest.java
@@ -1038,6 +1038,10 @@ void commit() {
               "SyncDataConn 2 committed",
               "AsyncDataConn 3 committed",
               "SyncDataConn 4 committed",
+              "AsyncDataConn 1 post committed",
+              "SyncDataConn 2 post committed",
+              "AsyncDataConn 3 post committed",
+              "SyncDataConn 4 post committed",
               "SyncDataConn 4 closed",
               "AsyncDataConn 3 closed",
               "SyncDataConn 2 closed",
@@ -2055,70 +2059,14 @@ void force_back() {
               "SyncDataConn 2 committed",
               "AsyncDataConn 3 committed",
               "SyncDataConn 4 committed",
-              "AsyncDataConn 1 forced back",
-              "SyncDataConn 2 forced back",
-              "AsyncDataConn 3 forced back",
-              "SyncDataConn 4 forced back",
-              "SyncDataConn 4 closed",
-              "AsyncDataConn 3 closed",
-              "SyncDataConn 2 closed",
-              "AsyncDataConn 1 closed",
-              "SyncDataSrc 4 closed",
-              "AsyncDataSrc 3 closed",
-              "SyncDataSrc 2 closed",
-              "AsyncDataSrc 1 closed");
-    }
-
-    @Test
-    void post_commit() {
-      var logger = new ArrayList<String>();
-
-      DataHubInner.usesGlobal("foo", new AsyncDataSrc(1, FAIL__NOT, logger));
-      DataHubInner.usesGlobal("bar", new SyncDataSrc(2, FAIL__NOT, logger));
-
-      try (var ac = DataHubInner.setupGlobals()) {
-        suppressWarnings_unused(ac);
-        var hub = new DataHubInner();
-
-        hub.uses("baz", new AsyncDataSrc(3, FAIL__NOT, logger));
-        hub.uses("qux", new SyncDataSrc(4, FAIL__NOT, logger));
-
-        hub.begin();
-
-        var conn1 = hub.getDataConn("foo", AsyncDataConn.class);
-        assertThat(conn1).isNotNull();
-
-        var conn2 = hub.getDataConn("bar", SyncDataConn.class);
-        assertThat(conn2).isNotNull();
-
-        var conn3 = hub.getDataConn("baz", AsyncDataConn.class);
-        assertThat(conn3).isNotNull();
-
-        var conn4 = hub.getDataConn("qux", SyncDataConn.class);
-        assertThat(conn4).isNotNull();
-
-        hub.postCommit();
-        hub.end();
-
-        hub.close();
-      } catch (Exception e) {
-        fail(e);
-      }
-
-      assertThat(logger)
-          .containsExactly(
-              "SyncDataSrc 2 setupped",
-              "AsyncDataSrc 1 setupped",
-              "SyncDataSrc 4 setupped",
-              "AsyncDataSrc 3 setupped",
-              "AsyncDataSrc 1 created DataConn",
-              "SyncDataSrc 2 created DataConn",
-              "AsyncDataSrc 3 created DataConn",
-              "SyncDataSrc 4 created DataConn",
               "AsyncDataConn 1 post committed",
               "SyncDataConn 2 post committed",
               "AsyncDataConn 3 post committed",
               "SyncDataConn 4 post committed",
+              "AsyncDataConn 1 forced back",
+              "SyncDataConn 2 forced back",
+              "AsyncDataConn 3 forced back",
+              "SyncDataConn 4 forced back",
               "SyncDataConn 4 closed",
               "AsyncDataConn 3 closed",
               "SyncDataConn 2 closed",