From 267e4d06b0340c1ea0792623995b36b159dd63cc Mon Sep 17 00:00:00 2001
From: Britt Park <britt.park@alfresco.com>
Date: Tue, 31 Oct 2006 15:17:09 +0000
Subject: [PATCH] A more scalable implementation of getCommonAncestor. 
 Performance is roughly proportional to the distance of the common ancestor
 from the compared nodes.

git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/BRANCHES/WCM-DEV2/root@4265 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261
---
 .../org/alfresco/repo/avm/AVMRepository.java  | 47 +++++++++++++------
 1 file changed, 33 insertions(+), 14 deletions(-)

diff --git a/source/java/org/alfresco/repo/avm/AVMRepository.java b/source/java/org/alfresco/repo/avm/AVMRepository.java
index f61bd2c879..5719aafb3c 100644
--- a/source/java/org/alfresco/repo/avm/AVMRepository.java
+++ b/source/java/org/alfresco/repo/avm/AVMRepository.java
@@ -1709,24 +1709,43 @@ public class AVMRepository
             throw new AVMNotFoundException("Node not found.");
         }
         List<AVMNode> leftHistory = new ArrayList<AVMNode>();
-        while (lNode != null)
-        {
-            leftHistory.add(lNode);
-            lNode = lNode.getAncestor();
-        }
         List<AVMNode> rightHistory = new ArrayList<AVMNode>();
-        while (rNode != null)
+        while (lNode != null || rNode != null)
         {
-            rightHistory.add(rNode);
-            rNode = rNode.getAncestor();
-        }
-        for (AVMNode l : leftHistory)
-        {
-            for (AVMNode r : rightHistory)
+            boolean checkRight = false;
+            if (lNode != null)
             {
-                if (l.equals(r))
+                leftHistory.add(lNode);
+                checkRight = true;
+                lNode = lNode.getAncestor();
+            }
+            boolean checkLeft = false;
+            if (rNode != null)
+            {
+                rightHistory.add(rNode);
+                checkLeft = true;
+                rNode = rNode.getAncestor();
+            }
+            if (checkRight)
+            {
+                AVMNode check = leftHistory.get(leftHistory.size() - 1);
+                for (AVMNode node : rightHistory)
                 {
-                    return l.getDescriptor("", "", "");
+                    if (node.equals(check))
+                    {
+                        return node.getDescriptor("", "", "");
+                    }
+                }
+            }
+            if (checkLeft)
+            {
+                AVMNode check = rightHistory.get(rightHistory.size() - 1);
+                for (AVMNode node : leftHistory)
+                {
+                    if (node.equals(check))
+                    {
+                        return node.getDescriptor("", "", "");
+                    }
                 }
             }
         }