--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/impl/TreeRepository.java	Mon Dec 10 18:50:53 2012 +0900
@@ -0,0 +1,33 @@
+package jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.impl;
+
+import java.util.concurrent.atomic.AtomicReference;
+
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.Command;
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.Constants;
+
+import fj.data.List;
+
+public class TreeRepository
+{
+	private final AtomicReference<ChangeSetImpl> changeSet;
+	
+	public TreeRepository()
+	{
+		List<Command> emptyCommands = List.nil();
+		
+		changeSet = new AtomicReference<ChangeSetImpl>(
+				new ChangeSetImpl(TreeImpl.EMPTY,emptyCommands,
+						Constants.DEFAULT_OWNER,Constants.DEFAULT_REVISION_START_NUMBER,null)
+			);
+	}
+	
+	public ChangeSetImpl getCurrentChangeSet()
+	{
+		return changeSet.get();
+	}
+	
+	public boolean commitChangeSet(ChangeSetImpl _newChangeSet,ChangeSetImpl _currentChangeSet)
+	{
+		return changeSet.compareAndSet(_currentChangeSet,_newChangeSet);
+	}
+}