From 19b4618fb5eca3a9212caafecb1e7ad85ce78bd4 Mon Sep 17 00:00:00 2001
From: Juergen Hoeller <jhoeller@vmware.com>
Date: Mon, 22 Mar 2010 14:23:02 +0000
Subject: [PATCH] avoid Synchronization List preparations upfront if possible
 (SPR-6999)

---
 .../jta/WebSphereUowTransactionManager.java   |  4 +++-
 .../AbstractPlatformTransactionManager.java   |  4 ++--
 .../TransactionSynchronizationManager.java    | 20 ++++++++++---------
 3 files changed, 16 insertions(+), 12 deletions(-)

diff --git a/org.springframework.transaction/src/main/java/org/springframework/transaction/jta/WebSphereUowTransactionManager.java b/org.springframework.transaction/src/main/java/org/springframework/transaction/jta/WebSphereUowTransactionManager.java
index c5fbafa5376..e2349a4f56c 100644
--- a/org.springframework.transaction/src/main/java/org/springframework/transaction/jta/WebSphereUowTransactionManager.java
+++ b/org.springframework.transaction/src/main/java/org/springframework/transaction/jta/WebSphereUowTransactionManager.java
@@ -352,7 +352,9 @@ public class WebSphereUowTransactionManager extends JtaTransactionManager
 				if (status.isNewSynchronization()) {
 					List<TransactionSynchronization> synchronizations = TransactionSynchronizationManager.getSynchronizations();
 					TransactionSynchronizationManager.clear();
-					uowManager.registerInterposedSynchronization(new JtaAfterCompletionSynchronization(synchronizations));
+					if (!synchronizations.isEmpty()) {
+						uowManager.registerInterposedSynchronization(new JtaAfterCompletionSynchronization(synchronizations));
+					}
 				}
 			}
 		}
diff --git a/org.springframework.transaction/src/main/java/org/springframework/transaction/support/AbstractPlatformTransactionManager.java b/org.springframework.transaction/src/main/java/org/springframework/transaction/support/AbstractPlatformTransactionManager.java
index f0f0a1724e6..ee147383c13 100644
--- a/org.springframework.transaction/src/main/java/org/springframework/transaction/support/AbstractPlatformTransactionManager.java
+++ b/org.springframework.transaction/src/main/java/org/springframework/transaction/support/AbstractPlatformTransactionManager.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2009 the original author or authors.
+ * Copyright 2002-2010 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -970,7 +970,7 @@ public abstract class AbstractPlatformTransactionManager implements PlatformTran
 				// invoke the afterCompletion callbacks immediately
 				invokeAfterCompletion(synchronizations, completionStatus);
 			}
-			else {
+			else if (!synchronizations.isEmpty()) {
 				// Existing transaction that we participate in, controlled outside
 				// of the scope of this Spring transaction manager -> try to register
 				// an afterCompletion callback with the existing (JTA) transaction.
diff --git a/org.springframework.transaction/src/main/java/org/springframework/transaction/support/TransactionSynchronizationManager.java b/org.springframework.transaction/src/main/java/org/springframework/transaction/support/TransactionSynchronizationManager.java
index 392a0042a62..e68398389fa 100644
--- a/org.springframework.transaction/src/main/java/org/springframework/transaction/support/TransactionSynchronizationManager.java
+++ b/org.springframework.transaction/src/main/java/org/springframework/transaction/support/TransactionSynchronizationManager.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2009 the original author or authors.
+ * Copyright 2002-2010 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -287,16 +287,21 @@ public abstract class TransactionSynchronizationManager {
 	 * @see TransactionSynchronization
 	 */
 	public static List<TransactionSynchronization> getSynchronizations() throws IllegalStateException {
-		if (!isSynchronizationActive()) {
+		List<TransactionSynchronization> synchs = synchronizations.get();
+		if (synchs == null) {
 			throw new IllegalStateException("Transaction synchronization is not active");
 		}
-		List<TransactionSynchronization> synchs = synchronizations.get();
-		// Sort lazily here, not in registerSynchronization.
-		OrderComparator.sort(synchs);
 		// Return unmodifiable snapshot, to avoid ConcurrentModificationExceptions
 		// while iterating and invoking synchronization callbacks that in turn
 		// might register further synchronizations.
-		return Collections.unmodifiableList(new ArrayList<TransactionSynchronization>(synchs));
+		if (synchs.isEmpty()) {
+			return Collections.emptyList();
+		}
+		else {
+			// Sort lazily here, not in registerSynchronization.
+			OrderComparator.sort(synchs);
+			return Collections.unmodifiableList(new ArrayList<TransactionSynchronization>(synchs));
+		}
 	}
 
 	/**
@@ -359,9 +364,6 @@ public abstract class TransactionSynchronizationManager {
 	 * flush mode of a Hibernate Session to "FlushMode.NEVER" upfront.
 	 * @see org.springframework.transaction.TransactionDefinition#isReadOnly()
 	 * @see TransactionSynchronization#beforeCommit(boolean)
-	 * @see org.hibernate.Session#flush
-	 * @see org.hibernate.Session#setFlushMode
-	 * @see org.hibernate.FlushMode#NEVER
 	 */
 	public static boolean isCurrentTransactionReadOnly() {
 		return (currentTransactionReadOnly.get() != null);