From 65ed12c55e5076fc6cb9120d5ae5c02472b6cfa3 Mon Sep 17 00:00:00 2001
From: John May <john.wilkinsonmay@gmail.com>
Date: Mon, 10 Dec 2012 13:54:01 +0000
Subject: [PATCH] corrected handling of null value in the TreeNodeComparator.
 Previous if any node or atom were null the comparator would return '0' which
 is incorrect. If one is null and the other is not the objects are not equal.

Change-Id: I928a6832ec15cdf5fad67a9dec41bcec51b05db1
Signed-off-by: Egon Willighagen <egonw@users.sourceforge.net>

Conflicts:
	src/main/org/openscience/cdk/tools/HOSECodeGenerator.java
---
 .../cdk/tools/HOSECodeGenerator.java          | 40 +++++++++++--------
 1 file changed, 24 insertions(+), 16 deletions(-)

diff --git a/src/main/org/openscience/cdk/tools/HOSECodeGenerator.java b/src/main/org/openscience/cdk/tools/HOSECodeGenerator.java
index 302f09bd65e..4bc36fcdc4c 100644
--- a/src/main/org/openscience/cdk/tools/HOSECodeGenerator.java
+++ b/src/main/org/openscience/cdk/tools/HOSECodeGenerator.java
@@ -733,25 +733,33 @@ class TreeNodeComparator implements Comparator<TreeNode> {
     /**
      *The compare method, compares by canonical label of atoms
      *
-     * @param  obj1  The first TreeNode
-     * @param  obj2  The second TreeNode
+     * @param  a  The first TreeNode
+     * @param  b  The second TreeNode
      * @return       -1,0,1
      */
-    public int compare(TreeNode obj1, TreeNode obj2) {
-    	if(obj1==null || obj2==null || ((TreeNode) obj1).getAtom()==null || ((TreeNode) obj2).getAtom()==null)
-    		return 0;
-    	Long label1 = (Long)((TreeNode) obj1).getAtom().getProperty(InvPair.CANONICAL_LABEL);
-    	Long label2 = (Long)((TreeNode) obj2).getAtom().getProperty(InvPair.CANONICAL_LABEL);
-    	if(label1==null || label2==null)
-    		return 0;
-    	if (label1.intValue() < label2.intValue()) {
-    		return (-1);
-    	}
-    	if (label1.intValue() > label2.intValue()) {
-    		return (1);
-    	}
-    	return (0);
+    public int compare(TreeNode a, TreeNode b) {
+        return label(a).compareTo(label(b));
     }
+
+    /**
+     * Access the canonical label for the given tree node's atom. If any component is null
+     * then {@link Long#MIN_VALUE} is return thus sorting that object in lower order.
+     * @param node a tree node to get the label from
+     * @return canonical label value
+     */
+    private Long label(TreeNode node){
+        if(node == null)
+            return Long.MIN_VALUE;
+        IAtom atom = node.getAtom();
+        if(atom == null)
+            return Long.MIN_VALUE;
+        // cast can be removed in master
+        Long label = (Long) atom.getProperty(InvPair.CANONICAL_LABEL);
+        if(label == null)
+            return Long.MIN_VALUE;
+        return label;
+    }
+
   }
     
   /**