From 4b17d309cb86ce90c9d4c9e4626b3c2b7fda0909 Mon Sep 17 00:00:00 2001
From: Andrei Koval <andrei.koval@neo4j.com>
Date: Thu, 8 Feb 2018 08:44:17 +0100
Subject: [PATCH] Replaced Stack with Deque

---
 .../kernel/impl/locking/community/RagManager.java      | 10 +++++-----
 .../core/replication/session/LocalSessionPool.java     |  5 +++--
 2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/community/kernel/src/main/java/org/neo4j/kernel/impl/locking/community/RagManager.java b/community/kernel/src/main/java/org/neo4j/kernel/impl/locking/community/RagManager.java
index 602336909f763..22ca165c2b65d 100644
--- a/community/kernel/src/main/java/org/neo4j/kernel/impl/locking/community/RagManager.java
+++ b/community/kernel/src/main/java/org/neo4j/kernel/impl/locking/community/RagManager.java
@@ -19,12 +19,13 @@
  */
 package org.neo4j.kernel.impl.locking.community;
 
+import java.util.ArrayDeque;
+import java.util.Deque;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
-import java.util.Stack;
 
 import org.neo4j.kernel.DeadlockDetectedException;
 import org.neo4j.kernel.impl.util.ArrayMap;
@@ -132,7 +133,7 @@ synchronized void checkWaitOn( Object resource, Object tx )
 
         Iterator<Object> itr = lockingTxList.iterator();
         List<Object> checkedTransactions = new LinkedList<>();
-        Stack<Object> graphStack = new Stack<>();
+        final Deque<Object> graphStack = new ArrayDeque<>();
         // has resource,transaction interleaved
         graphStack.push( resource );
         while ( itr.hasNext() )
@@ -162,8 +163,7 @@ synchronized void checkWaitOn( Object resource, Object tx )
                 continue;
             }
             graphStack.push( lockingTx );
-            checkWaitOnRecursive( lockingTx, tx, checkedTransactions,
-                    graphStack );
+            checkWaitOnRecursive( lockingTx, tx, checkedTransactions, graphStack );
             graphStack.pop();
         }
 
@@ -173,7 +173,7 @@ synchronized void checkWaitOn( Object resource, Object tx )
 
     private synchronized void checkWaitOnRecursive( Object lockingTx,
                                                     Object waitingTx, List<Object> checkedTransactions,
-                                                    Stack<Object> graphStack ) throws DeadlockDetectedException
+                                                    Deque<Object> graphStack ) throws DeadlockDetectedException
     {
         if ( lockingTx.equals( waitingTx ) )
         {
diff --git a/enterprise/causal-clustering/src/main/java/org/neo4j/causalclustering/core/replication/session/LocalSessionPool.java b/enterprise/causal-clustering/src/main/java/org/neo4j/causalclustering/core/replication/session/LocalSessionPool.java
index d57e8f3063074..1837065537f81 100644
--- a/enterprise/causal-clustering/src/main/java/org/neo4j/causalclustering/core/replication/session/LocalSessionPool.java
+++ b/enterprise/causal-clustering/src/main/java/org/neo4j/causalclustering/core/replication/session/LocalSessionPool.java
@@ -19,13 +19,14 @@
  */
 package org.neo4j.causalclustering.core.replication.session;
 
+import java.util.ArrayDeque;
+import java.util.Deque;
 import java.util.EmptyStackException;
-import java.util.Stack;
 
 /** Keeps a pool of local sub-sessions, to be used under a single global session. */
 public class LocalSessionPool
 {
-    private final Stack<LocalSession> sessionStack = new Stack<>();
+    private final Deque<LocalSession> sessionStack = new ArrayDeque<>();
 
     private final GlobalSession globalSession;
     private long nextLocalSessionId;