From 9f990f47c46a763fba1cea3006965ba16a3ad96d Mon Sep 17 00:00:00 2001
From: Philippe Marschall <philippe.marschall@gmail.com>
Date: Thu, 30 Jul 2015 19:12:46 +0200
Subject: [PATCH] BATCH-2408 Use ArrayList instead of Stack

Stack is a pre Java 1.2 class that is slower than ArrayList as it
incurs additional synchronization overhead.

 - replace Stack with ArrayList where it's not public API

Issue: BATCH-2408
---
 .../ResourcelessTransactionManager.java        | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/spring-batch-infrastructure/src/main/java/org/springframework/batch/support/transaction/ResourcelessTransactionManager.java b/spring-batch-infrastructure/src/main/java/org/springframework/batch/support/transaction/ResourcelessTransactionManager.java
index 8073206bc..19300b4a3 100644
--- a/spring-batch-infrastructure/src/main/java/org/springframework/batch/support/transaction/ResourcelessTransactionManager.java
+++ b/spring-batch-infrastructure/src/main/java/org/springframework/batch/support/transaction/ResourcelessTransactionManager.java
@@ -16,7 +16,8 @@
 
 package org.springframework.batch.support.transaction;
 
-import java.util.Stack;
+import java.util.ArrayList;
+import java.util.List;
 
 import org.springframework.transaction.TransactionDefinition;
 import org.springframework.transaction.TransactionException;
@@ -42,17 +43,17 @@ public class ResourcelessTransactionManager extends AbstractPlatformTransactionM
     @Override
 	protected Object doGetTransaction() throws TransactionException {
 		Object transaction = new ResourcelessTransaction();
-		Stack<Object> resources;
+		List<Object> resources;
 		if (!TransactionSynchronizationManager.hasResource(this)) {
-			resources = new Stack<Object>();
+			resources = new ArrayList<Object>();
 			TransactionSynchronizationManager.bindResource(this, resources);
 		}
 		else {
 			@SuppressWarnings("unchecked")
-			Stack<Object> stack = (Stack<Object>) TransactionSynchronizationManager.getResource(this);
+			List<Object> stack = (List<Object>) TransactionSynchronizationManager.getResource(this);
 			resources = stack;
 		}
-		resources.push(transaction);
+		resources.add(transaction);
 		return transaction;
 	}
 
@@ -66,8 +67,7 @@ public class ResourcelessTransactionManager extends AbstractPlatformTransactionM
     @Override
 	protected boolean isExistingTransaction(Object transaction) throws TransactionException {
 		if (TransactionSynchronizationManager.hasResource(this)) {
-			@SuppressWarnings("unchecked")
-			Stack<Object> stack = (Stack<Object>) TransactionSynchronizationManager.getResource(this);
+			List<?> stack = (List<?>) TransactionSynchronizationManager.getResource(this);
 			return stack.size() > 1;
 		}
 		return ((ResourcelessTransaction) transaction).isActive();
@@ -79,9 +79,7 @@ public class ResourcelessTransactionManager extends AbstractPlatformTransactionM
 
     @Override
 	protected void doCleanupAfterCompletion(Object transaction) {
-		@SuppressWarnings("unchecked")
-		Stack<Object> list = (Stack<Object>) TransactionSynchronizationManager.getResource(this);
-		Stack<Object> resources = list;
+		List<?> resources = (List<?>) TransactionSynchronizationManager.getResource(this);
 		resources.clear();
 		TransactionSynchronizationManager.unbindResource(this);
 		((ResourcelessTransaction) transaction).clear();