don't begin new transaction

Persistence code was not checking to see if a transaction was already
in progress before beginning a transaction.
Fix checkstyle issue with comments and parameter for EntityMgrException.
Restore other checkstyle fixes.
More checkstyle fixes.
Rename some variables.

Change-Id: Ic820944781571ba2ef411cb86d12fa32fb206124
Issue-ID: POLICY-1106
Signed-off-by: Jim Hahn <jrh3@att.com>

1 files changed, 44 insertions, 18 deletions

diff --git a/feature-session-persistence/src/main/java/org/onap/policy/drools/persistence/EntityMgrTrans.java b/feature-session-persistence/src/main/java/org/onap/policy/drools/persistence/EntityMgrTrans.java
index 3d276519..988cd9c2 100644
--- a/feature-session-persistence/src/main/java/org/onap/policy/drools/persistence/EntityMgrTrans.java
+++ b/feature-session-persistence/src/main/java/org/onap/policy/drools/persistence/EntityMgrTrans.java
@@ -28,27 +28,40 @@ import javax.transaction.RollbackException;
 import javax.transaction.Status;
 import javax.transaction.SystemException;
 import javax.transaction.UserTransaction;
-
 import org.onap.policy.common.utils.jpa.EntityMgrCloser;
 
 /**
- * Wrapper for an <i>EntityManager</i> that creates a JTA transaction that is auto-rolled back when
- * closed.
+ * Wrapper for an <i>EntityManager</i> that creates a JTA transaction that is auto-rolled
+ * back when closed. Note: commit() and rollback() actions do nothing if a transaction was
+ * already in progress when this object was constructed.
  */
 public class EntityMgrTrans extends EntityMgrCloser {
 
-    /** Transaction to be rolled back. */
+    /**
+     * Transaction to be rolled back.
+     */
     private static UserTransaction userTrans = com.arjuna.ats.jta.UserTransaction.userTransaction();
 
     /**
+     * {@code True} if a transaction had already been started before this object was
+     * constructed, {@code false} otherwise.
+     */
+    private boolean transInProgress;
+
+    /**
      * Constructor.
-     * 
-     *  @param em entity for which a transaction is to be begun */
+     *
+     * @param em entity for which a transaction is to be begun
+     */
     public EntityMgrTrans(EntityManager em) {
         super(em);
 
         try {
-            userTrans.begin();
+            transInProgress = (userTrans.getStatus() == Status.STATUS_ACTIVE);
+            if (!transInProgress) {
+                userTrans.begin();
+            }
+
             em.joinTransaction();
 
         } catch (RuntimeException | NotSupportedException | SystemException e) {
@@ -75,24 +88,32 @@ public class EntityMgrTrans extends EntityMgrCloser {
         EntityMgrTrans.userTrans = userTrans;
     }
 
-    /** Commits the transaction. */
+    /**
+     * Commits the transaction.
+     */
     public void commit() {
+        if (transInProgress) {
+            return;
+        }
+
         try {
             userTrans.commit();
 
-        } catch (SecurityException
-                | IllegalStateException
-                | RollbackException
-                | HeuristicMixedException
-                | HeuristicRollbackException
-                | SystemException e) {
+        } catch (SecurityException | IllegalStateException | RollbackException | HeuristicMixedException
+                        | HeuristicRollbackException | SystemException e) {
 
             throw new EntityMgrException(e);
         }
     }
 
-    /** Rolls back the transaction. */
+    /**
+     * Rolls back the transaction.
+     */
     public void rollback() {
+        if (transInProgress) {
+            return;
+        }
+
         try {
             userTrans.rollback();
 
@@ -104,7 +125,7 @@ public class EntityMgrTrans extends EntityMgrCloser {
     @Override
     public void close() {
         try {
-            if (userTrans.getStatus() == Status.STATUS_ACTIVE) {
+            if (!transInProgress && userTrans.getStatus() == Status.STATUS_ACTIVE) {
                 userTrans.rollback();
             }
 
@@ -117,12 +138,17 @@ public class EntityMgrTrans extends EntityMgrCloser {
     }
 
     /**
-     * Runtime exceptions generated by this class. Wraps exceptions generated by delegated operations,
-     * particularly when they are not, themselves, Runtime exceptions.
+     * Runtime exceptions generated by this class. Wraps exceptions generated by delegated
+     * operations, particularly when they are not, themselves, Runtime exceptions.
      */
     public static class EntityMgrException extends RuntimeException {
         private static final long serialVersionUID = 1L;
 
+        /**
+         * Constructor.
+         * 
+         * @param ex exception to be wrapped
+         */
         public EntityMgrException(Exception ex) {
             super(ex);
         }