Make LocalTransactionManager more useful (#609)

* Add convenient constructors to LocalTransactionManager

* Provide LocalTransaction from LocalTransactionManager

* Add javadoc comments

Author: nakamura-to

doma-core/src/main/java/org/seasar/doma/jdbc/tx/LocalTransactionManager.java

@@ -4,19 +4,82 @@
 
 import java.util.function.Supplier;
 import org.seasar.doma.DomaNullPointerException;
+import org.seasar.doma.jdbc.JdbcLogger;
 
-/** A transaction manager for local transactions. */
+/**
+ * A transaction manager for local transactions.
+ *
+ * <p>This instance is thread safe.
+ */
 public class LocalTransactionManager implements TransactionManager {
 
   protected final LocalTransaction transaction;
 
+  /**
+   * Create an instance.
+   *
+   * @param transaction the transaction
+   * @throws DomaNullPointerException if the {@code transaction} is {@code null}
+   */
   public LocalTransactionManager(LocalTransaction transaction) {
     if (transaction == null) {
       throw new DomaNullPointerException("transaction");
     }
     this.transaction = transaction;
   }
 
+  /**
+   * Create an instance.
+   *
+   * @param dataSource the data source
+   * @param jdbcLogger the logger
+   * @throws DomaNullPointerException if any of the parameters are {@code null}
+   */
+  public LocalTransactionManager(LocalTransactionDataSource dataSource, JdbcLogger jdbcLogger) {
+    if (dataSource == null) {
+      throw new DomaNullPointerException("dataSource");
+    }
+    if (jdbcLogger == null) {
+      throw new DomaNullPointerException("jdbcLogger");
+    }
+    this.transaction = dataSource.getLocalTransaction(jdbcLogger);
+  }
+
+  /**
+   * Create an instance.
+   *
+   * @param dataSource the data source
+   * @param jdbcLogger the logger
+   * @param isolationLevel the default transaction isolation level
+   * @throws DomaNullPointerException if any of the parameters are {@code null}
+   */
+  public LocalTransactionManager(
+      LocalTransactionDataSource dataSource,
+      JdbcLogger jdbcLogger,
+      TransactionIsolationLevel isolationLevel) {
+    if (dataSource == null) {
+      throw new DomaNullPointerException("dataSource");
+    }
+    if (jdbcLogger == null) {
+      throw new DomaNullPointerException("jdbcLogger");
+    }
+    if (isolationLevel == null) {
+      throw new DomaNullPointerException("isolationLevel");
+    }
+    this.transaction = dataSource.getLocalTransaction(jdbcLogger, isolationLevel);
+  }
+
+  /**
+   * Returns the transaction.
+   *
+   * <p>This method is mainly used in test code.
+   *
+   * @return the transaction
+   */
+  public LocalTransaction getTransaction() {
+    return transaction;
+  }
+
   @Override
   public void required(Runnable block) {
     if (block == null) {

doma-core/src/test/java/org/seasar/doma/jdbc/tx/LocalTransactionManagerTest.java

@@ -1,6 +1,7 @@
 package org.seasar.doma.jdbc.tx;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -132,4 +133,23 @@ public void testNotSupported_in_tx() {
     log.append(LocalTransactionManagerTest.counter);
     assertEquals("01110", log.toString());
   }
+
+  @Test
+  public void testConstructor1() {
+    LocalTransactionManager manager = new LocalTransactionManager(transaction);
+    assertNotNull(manager);
+  }
+
+  @Test
+  public void testConstructor2() {
+    LocalTransactionManager manager = new LocalTransactionManager(dataSource, jdbcLogger);
+    assertNotNull(manager);
+  }
+
+  @Test
+  public void testConstructor3() {
+    LocalTransactionManager manager =
+        new LocalTransactionManager(dataSource, jdbcLogger, TransactionIsolationLevel.SERIALIZABLE);
+    assertNotNull(manager);
+  }
 }