new-tx-i: new Tx interface pattern

Author: Alexander Lavrukov

repository-test/src/main/java/tech/ydb/yoj/repository/test/RepositoryTest.java

@@ -2,6 +2,9 @@
 
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Iterators;
+import lombok.AccessLevel;
+import lombok.AllArgsConstructor;
+import lombok.RequiredArgsConstructor;
 import org.assertj.core.api.Assertions;
 import org.junit.Assert;
 import org.junit.Test;
@@ -288,13 +291,45 @@ public void deferFinallyRollbackRetryable() {
 
     @Test
     public void deferFinallyNotInTxContext() {
-        db.tx(() -> Tx.Current.get().deferFinally(() -> assertFalse(Tx.Current.exists())));
+        db.txC(tx -> tx.deferFinally(() -> assertFalse(Tx.Current.exists())));
+    }
+
+    @Test
+    public void myTest() {
+        db.txC(tx -> {
+            // new. Usefull because you see that table depends on tx;
+            Db1.project(tx).findAll();
+
+            // new. Usefull because you can initialize db one time in tx and use call table without pass tx any time
+            Db2.of(tx).project().findAll();
+
+            // old
+            db.projects().findAll();
+        });
+    }
+
+    // Examples of new DB patterns. User can use one or both;
+
+    @AllArgsConstructor(access = AccessLevel.PRIVATE)
+    final static class Db1 {
+        public static TestEntityOperations.ProjectTable project(Tx tx) {
+            return new TestEntityOperations.ProjectTable(tx.table(Project.class));
+        }
+    }
+
+    @RequiredArgsConstructor(staticName = "of")
+    final static class Db2 {
+        private final Tx tx;
+
+        TestEntityOperations.ProjectTable project() {
+            return new TestEntityOperations.ProjectTable(tx.table(Project.class));
+        }
     }
 
     @Test
     public void deferFinallyRollbackNotInTxContext() {
-        assertThatExceptionOfType(RuntimeException.class).isThrownBy(() -> db.tx(() -> {
-            Tx.Current.get().deferFinally(() -> assertFalse(Tx.Current.exists()));
+        assertThatExceptionOfType(RuntimeException.class).isThrownBy(() -> db.txC(tx -> {
+            tx.deferFinally(() -> assertFalse(Tx.Current.exists()));
             throw new RuntimeException();
         }));
     }

repository/src/main/java/tech/ydb/yoj/repository/db/Tx.java

@@ -6,6 +6,10 @@
 import java.util.function.Supplier;
 
 public interface Tx {
+    default <T extends Entity<T>> Table<T> table(Class<T> cls) {
+        return getRepositoryTransaction().table(cls);
+    }
+
     void defer(Runnable runnable);
 
     void deferFinally(Runnable runnable);

repository/src/main/java/tech/ydb/yoj/repository/db/TxManager.java

@@ -7,6 +7,8 @@
 import tech.ydb.yoj.repository.db.exception.RetryableException;
 
 import java.time.Duration;
+import java.util.function.Consumer;
+import java.util.function.Function;
 import java.util.function.Supplier;
 
 public interface TxManager {
@@ -137,7 +139,9 @@ default TxManager noLogging() {
      * @param supplier action to perform
      * @return action result
      */
-    <T> T tx(Supplier<T> supplier);
+    default <T> T tx(Supplier<T> supplier) {
+        return txF(tx -> supplier.get());
+    }
 
     /**
      * Performs the specified action inside a transaction. The action must be idempotent, because it might be executed
@@ -146,7 +150,18 @@ default TxManager noLogging() {
      *
      * @param runnable action to perform
      */
-    void tx(Runnable runnable);
+    default void tx(Runnable runnable) {
+        txC(tx -> runnable.run());
+    }
+
+    <T> T txF(Function<Tx, T> supplier);
+
+    default void txC(Consumer<Tx> consumer) {
+        txF(tx -> {
+            consumer.accept(tx);
+            return null;
+        });
+    }
 
     /**
      * Start a transaction-like session of read-only statements. Each statement will be executed <em>separately</em>,