switched to volatile/double-checked lock

1 files changed, 18 insertions, 16 deletions

diff --git a/src/jvm/clojure/lang/IteratorSeq.java b/src/jvm/clojure/lang/IteratorSeq.java
index 20102034..8cc5d70d 100644
--- a/src/jvm/clojure/lang/IteratorSeq.java
+++ b/src/jvm/clojure/lang/IteratorSeq.java
@@ -13,9 +13,9 @@ package clojure.lang;
 import java.util.Iterator;

 

 public class IteratorSeq extends ASeq{

-Iterator iter;

-Object val;

-ISeq _rest;

+final Iterator iter;

+volatile Object val;

+volatile ISeq _rest;

 

 public static IteratorSeq create(Iterator iter){

 	if(iter.hasNext())

@@ -30,23 +30,25 @@ IteratorSeq(Iterator iter){
 }

 

 public Object first(){

-	synchronized(this)

-		{

-		if(val == this)

-			val = iter.next();

-		return val;

-		}

+	if(val == this)

+		synchronized(this)

+			{

+			if(val == this)

+				val = iter.next();

+			}

+	return val;

 }

 

 public ISeq rest(){

-	synchronized(this)

-		{

-		if(_rest == this)

+	if(_rest == this)

+		synchronized(this)

 			{

-			first();

-			_rest = create(iter);

+			if(_rest == this)

+				{

+				first();

+				_rest = create(iter);

+				}

 			}

-		return _rest;

-		}

+	return _rest;

 }

 }