#1245 - Refactor internals - Add to TransactionManager externalRemoveTransaction() and externalBeginTransaction()

These provide a better/tidier way for external transaction managers (like ebean-spring-txn) to begin and end externally
managed transactions.

src/test/java/io/ebeaninternal/api/TDSpiEbeanServer.java

@@ -1,6 +1,29 @@
 package io.ebeaninternal.api;
 
-import io.ebean.*;
+import io.ebean.AutoTune;
+import io.ebean.BackgroundExecutor;
+import io.ebean.BeanState;
+import io.ebean.CallableSql;
+import io.ebean.DocumentStore;
+import io.ebean.ExpressionFactory;
+import io.ebean.Filter;
+import io.ebean.FutureIds;
+import io.ebean.FutureList;
+import io.ebean.FutureRowCount;
+import io.ebean.PagedList;
+import io.ebean.PersistenceContextScope;
+import io.ebean.Query;
+import io.ebean.QueryIterator;
+import io.ebean.SqlQuery;
+import io.ebean.SqlRow;
+import io.ebean.SqlUpdate;
+import io.ebean.Transaction;
+import io.ebean.TransactionCallback;
+import io.ebean.TxScope;
+import io.ebean.Update;
+import io.ebean.UpdateQuery;
+import io.ebean.ValuePair;
+import io.ebean.Version;
 import io.ebean.annotation.TxIsolation;
 import io.ebean.bean.BeanCollection;
 import io.ebean.bean.CallStack;
@@ -138,6 +161,11 @@ public class TDSpiEbeanServer implements SpiEbeanServer {
     return null;
   }
 
+  @Override
+  public SpiTransactionManager getTransactionManager() {
+    return null;
+  }
+
   @Override
   public List<BeanDescriptor<?>> getBeanDescriptors() {
     return null;

src/test/java/io/ebeaninternal/server/transaction/TransactionManagerTest.java

@@ -0,0 +1,78 @@
+package io.ebeaninternal.server.transaction;
+
+import io.ebean.BaseTestCase;
+import io.ebean.Ebean;
+import io.ebean.Transaction;
+import io.ebean.TxScope;
+import io.ebeaninternal.api.ScopedTransaction;
+import io.ebeaninternal.api.SpiEbeanServer;
+import io.ebeaninternal.api.SpiTransaction;
+import io.ebeaninternal.api.SpiTransactionManager;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.tests.model.basic.Customer;
+
+import javax.sql.DataSource;
+import java.sql.Connection;
+import java.sql.SQLException;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class TransactionManagerTest extends BaseTestCase {
+
+  private static final Logger log = LoggerFactory.getLogger(TransactionManagerTest.class);
+
+  @Test
+  public void beginExternalTransaction() throws SQLException {
+
+    SpiEbeanServer server = spiEbeanServer();
+
+    SpiTransactionManager transactionManager = server.getTransactionManager();
+
+    DataSource dataSource = transactionManager.getDataSource();
+    Connection connection = dataSource.getConnection();
+
+    SpiTransaction externalTxn = new ExternalJdbcTransaction("external0", true, connection, null);
+
+    // push an externally managed transaction onto scope
+    ScopedTransaction scopedTransaction = transactionManager.externalBeginTransaction(externalTxn, TxScope.required());
+
+    Transaction current = Transaction.current();
+    assertThat(current).as("external transaction is in scope").isSameAs(scopedTransaction);
+
+    Customer.find.byName("In external");
+
+    log.info("inner begin");
+    Transaction inner = Ebean.beginTransaction();
+    try {
+
+      current = Transaction.current();
+      assertThat(current).as("still using external transaction, nested transaction pushed").isSameAs(scopedTransaction);
+
+      Customer.find.byName("In inner");
+      log.info("inner commit");
+      inner.commit();
+    } finally {
+      log.info("inner end");
+      inner.end();
+    }
+
+    current = Transaction.current();
+    assertThat(current).as("external transaction still in scope").isSameAs(scopedTransaction);
+
+    Customer.find.byName("external still active");
+
+
+    log.info("external transaction ends with commit and remove");
+    connection.commit();
+    // remove externally managed transaction out of scope
+    transactionManager.externalRemoveTransaction();
+
+
+    current = Transaction.current();
+    assertThat(current).as("external transaction out of scope").isNull();
+
+    Customer.find.byNameStatus("New implicit transaction", Customer.Status.ACTIVE);
+  }
+}