# HG changeset patch
# User Shoshi TAMAKI
# Date 1357827762 -32400
# Node ID 3ef2a66a8c5ddf9388f402ce5ba265ea70804052
# Parent  9fd57b7c6adb9e2f2ee00d1b34b4f1b11b250350
commit

diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/TreeEditResult.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/TreeEditResult.java	Mon Jan 07 23:22:36 2013 +0900
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,7 +0,0 @@
-package jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store;
-
-public interface TreeEditResult
-{
-	public TreeEditor getNewEditor();
-	public TreeEditResultStatus getStatus();
-}
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/TreeEditResultStatus.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/TreeEditResultStatus.java	Mon Jan 07 23:22:36 2013 +0900
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,6 +0,0 @@
-package jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store;
-
-public enum TreeEditResultStatus
-{
-	NODEPATH_NOTFOUND;
-}
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/TreeEditor.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/TreeEditor.java	Mon Jan 07 23:22:36 2013 +0900
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/TreeEditor.java	Thu Jan 10 23:22:42 2013 +0900
@@ -1,19 +1,18 @@
 package jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store;
 
 import java.nio.ByteBuffer;
-
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.trasnformer.NodeEditor;
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.Either;
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.Error;
 
 public interface TreeEditor
 {
 	public TraversableTree getTree();
-	public TreeEditResult appendChild(NodePath _path,int _pos);
-	public TreeEditResult deleteChild(NodePath _path,int _pos);
-	
-	public TreeEditResult putAttribute(NodePath _path,String _key,ByteBuffer _value);
-	public TreeEditResult deleteAttribute(NodePath _path,String _key);
-	
-	public TreeEditResult edit(NodePath _path,NodeEditor _transformer);
+	public Either<Error,TreeEditor> appendChild(NodePath _path,int _pos);
+	public Either<Error,TreeEditor> deleteChild(NodePath _path,int _pos);
+	public Either<Error,TreeEditor> putAttribute(NodePath _path,String _key,ByteBuffer _value);
+	public Either<Error,TreeEditor> deleteAttribute(NodePath _path,String _key);
+	public Either<Error,TreeEditor> edit(NodePath _path,NodeEditor _transformer);
 	
 	public boolean success();
 }
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/TreeEditorError.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/TreeEditorError.java	Thu Jan 10 23:22:42 2013 +0900
@@ -0,0 +1,9 @@
+package jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store;
+
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.Error;
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.DefaultError;
+
+public class TreeEditorError 
+{
+	public static final Error NODEPATH_NOTFOUND = new DefaultError();
+}
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/impl/DefaultAttributes.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/impl/DefaultAttributes.java	Mon Jan 07 23:22:36 2013 +0900
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/impl/DefaultAttributes.java	Thu Jan 10 23:22:42 2013 +0900
@@ -7,6 +7,8 @@
 import fj.data.TreeMap;
 
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.core.Attributes;
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.trasnformer.EditableAttributes;
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.trasnformer.EditableNode;
 
 public class DefaultAttributes implements Attributes
 {
@@ -39,4 +41,5 @@
 		Option<ByteBuffer> result = attrs.get(_key);
 		return result.isSome() ? result.some() : null;
 	}
+
 }
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/impl/DefaultChildren.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/impl/DefaultChildren.java	Mon Jan 07 23:22:36 2013 +0900
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/impl/DefaultChildren.java	Thu Jan 10 23:22:42 2013 +0900
@@ -17,10 +17,6 @@
 	private final List<DefaultNode> children;
 	private static final List<DefaultNode> EMPTY = List.nil();
 	
-	public enum Error{
-		INVALID_POSITION;
-	}
-	
 	public DefaultChildren()
 	{
 		this(EMPTY);
@@ -82,7 +78,7 @@
 	}
 
 	@Override
-	public EditableNode addNewChildAt(int _pos)
+	public Either<Error,EditableNode> addNewChildAt(int _pos)
 	{
 		
 		return null;
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/impl/DefaultNode.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/impl/DefaultNode.java	Mon Jan 07 23:22:36 2013 +0900
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/impl/DefaultNode.java	Thu Jan 10 23:22:42 2013 +0900
@@ -1,21 +1,32 @@
 package jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.impl;
 
+import java.nio.ByteBuffer;
+import java.util.Iterator;
+
+import fj.Ord;
+import fj.data.List;
+import fj.data.Option;
+import fj.data.TreeMap;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.core.Node;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.trasnformer.EditableAttributes;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.trasnformer.EditableChildren;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.trasnformer.EditableNode;
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.Either;
 
 public class DefaultNode implements EditableNode
 {
-	public final DefaultAttributes attrs;
-	public final DefaultChildren children;
+	public List<DefaultNode> children;
+	public TreeMap<String,ByteBuffer> attrs;
+	
+	private static final List<DefaultNode> NIL_LIST = List.nil();
+	private static final TreeMap<String,ByteBuffer> NIL_MAP = TreeMap.empty(Ord.stringOrd);
 	
 	public DefaultNode()
 	{
-		this(new DefaultChildren(),new DefaultAttributes());
+		this(NIL_LIST,NIL_MAP);
 	}
 	
-	public DefaultNode(DefaultChildren _children,DefaultAttributes _attrs)
+	public DefaultNode(List<DefaultNode> _children,TreeMap<String,ByteBuffer> _attrs)
 	{
 		attrs = _attrs;
 		children = _children;
@@ -24,12 +35,12 @@
 	@Override
 	public EditableChildren getChildren()
 	{
-		return children;
+		return new DefaultChildren(children,attrs);
 	}
 
 	@Override
 	public EditableAttributes getAttributes()
 	{
-		return attrs;
+		return new DefaultAttributes(children,attrs);
 	}
 }
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/impl/DefaultTraversableTree.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/impl/DefaultTraversableTree.java	Mon Jan 07 23:22:36 2013 +0900
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/impl/DefaultTraversableTree.java	Thu Jan 10 23:22:42 2013 +0900
@@ -3,8 +3,8 @@
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.core.Node;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.core.Tree;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.TraversableTree;
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.traverser.Traversal;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.traverser.TraverseEvaluator;
-import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.traverser.TraverseResult;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.traverser.Traverser;
 
 public class DefaultTraversableTree implements TraversableTree
@@ -25,7 +25,7 @@
 	}
 
 	@Override
-	public Iterable<TraverseResult> traverse(TraverseEvaluator _e)
+	public Iterable<Traversal> traverse(TraverseEvaluator _e)
 	{
 		return traverser.traverse(tree,_e);
 	}
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/impl/DefaultTreeEditResult.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/impl/DefaultTreeEditResult.java	Mon Jan 07 23:22:36 2013 +0900
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,29 +0,0 @@
-package jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.impl;
-
-import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.TreeEditResult;
-import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.TreeEditResultStatus;
-import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.TreeEditor;
-
-public class DefaultTreeEditResult implements TreeEditResult
-{
-	private final TreeEditor editor;
-	private final TreeEditResultStatus status;
-	
-	public DefaultTreeEditResult(TreeEditor _editor,TreeEditResultStatus _status)
-	{
-		editor = _editor;
-		status = _status;
-	}
-
-	@Override
-	public TreeEditor getNewEditor()
-	{
-		return editor;
-	}
-
-	@Override
-	public TreeEditResultStatus getStatus()
-	{
-		return status;
-	}
-}
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/impl/DefaultTreeEditor.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/impl/DefaultTreeEditor.java	Mon Jan 07 23:22:36 2013 +0900
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/impl/DefaultTreeEditor.java	Thu Jan 10 23:22:42 2013 +0900
@@ -8,9 +8,8 @@
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.ChangeList;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.NodePath;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.TraversableTree;
-import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.TreeEditResult;
-import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.TreeEditResultStatus;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.TreeEditor;
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.TreeEditorError;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.trasnformer.AppendChildAt;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.trasnformer.DeleteAttribute;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.trasnformer.DeleteChildAt;
@@ -18,8 +17,12 @@
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.trasnformer.SetAttribute;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.traverser.DefaultTraverseEvaluator;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.traverser.DefaultTraverser;
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.traverser.Traversal;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.traverser.TraverseResult;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.traverser.Traverser;
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.DefaultEither;
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.Either;
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.Error;
 
 public class DefaultTreeEditor implements TreeEditor
 {
@@ -39,26 +42,26 @@
 	}
 	
 	@Override
-	public TreeEditResult appendChild(NodePath _path,int _pos)
+	public Either<Error,TreeEditor> appendChild(NodePath _path,int _pos)
 	{
 		return edit(_path,new AppendChildAt(_pos));
 	}
 	
 
 	@Override
-	public TreeEditResult deleteChild(NodePath _path,int _pos)
+	public Either<Error,TreeEditor> deleteChild(NodePath _path,int _pos)
 	{
 		return edit(_path,new DeleteChildAt(_pos));
 	}
 
 	@Override
-	public TreeEditResult putAttribute(NodePath _path, String _key,ByteBuffer _value)
+	public Either<Error,TreeEditor> putAttribute(NodePath _path, String _key,ByteBuffer _value)
 	{
 		return edit(_path,new SetAttribute(_key,_value));
 	}
 
 	@Override
-	public TreeEditResult deleteAttribute(NodePath _path, String _key)
+	public Either<Error,TreeEditor> deleteAttribute(NodePath _path, String _key)
 	{
 		return edit(_path,new DeleteAttribute(_key));
 	}
@@ -70,23 +73,23 @@
 	}
 
 	@Override
-	public TreeEditResult edit(NodePath _path, NodeEditor _editor)
+	public Either<Error,TreeEditor> edit(NodePath _path, NodeEditor _editor)
 	{
 		Tree t = tip.getTree();
 		Traverser traverser = new DefaultTraverser();
 		DefaultTraverseEvaluator te = new DefaultTraverseEvaluator(_path);
-		Iterable<TraverseResult> result = traverser.traverse(t,te);
-		Iterator<TraverseResult> itr = result.iterator();
+		Iterable<Traversal> result = traverser.traverse(t,te);
+		Iterator<Traversal> itr = result.iterator();
 		
 		if(itr.hasNext()){
-			TraverseResult r = itr.next();
+			Traversal r = itr.next();
 			cloneAndApplyToNodeEditorFromRoot(r,_editor);
 		}
 		
-		return new DefaultTreeEditResult(null,TreeEditResultStatus.NODEPATH_NOTFOUND);
+		return DefaultEither.newA(TreeEditorError.NODEPATH_NOTFOUND);
 	}
 	
-	public void cloneAndApplyToNodeEditorFromRoot(TraverseResult _r,NodeEditor _editor)
+	public void cloneAndApplyToNodeEditorFromRoot(Traversal _r,NodeEditor _editor)
 	{
 		LinkedList<DefaultNode> path = new LinkedList<DefaultNode>();
 		
@@ -97,6 +100,4 @@
 		
 		
 	}
-	
-	
 }
\ No newline at end of file
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/impl/logger/LoggingAttributes.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/impl/logger/LoggingAttributes.java	Mon Jan 07 23:22:36 2013 +0900
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/impl/logger/LoggingAttributes.java	Thu Jan 10 23:22:42 2013 +0900
@@ -7,6 +7,8 @@
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.operations.SetAttributeOperation;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.trasnformer.EditableAttributes;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.trasnformer.EditableNode;
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.DefaultEither;
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.Either;
 
 public class LoggingAttributes implements EditableAttributes
 {
@@ -26,8 +28,14 @@
 	}
 
 	@Override
-	public EditableNode delete(final String _key)
+	public Either<Error,EditableNode> delete(final String _key)
 	{
+		
+		Either<Error,EditableNode> either = wrap.delete(_key);
+		if(either.isA()){
+			return either;
+		}
+		
 		Operation opDelete = new DeleteAttributeOperation(){
 			@Override
 			public String getKey(){
@@ -36,14 +44,20 @@
 		};
 		
 		Logger newLog = log.add(opDelete);
-		EditableNode newWrap = wrap.delete(_key);
+		EditableNode newWrap = either.b();
+		EditableNode newLoggingNode = new LoggingNode(newWrap,newLog);
 		
-		return new LoggingNode(newWrap,newLog);
+		return DefaultEither.newB(newLoggingNode);
 	}
 
 	@Override
-	public EditableNode put(final String _key,final ByteBuffer _value)
+	public Either<Error,EditableNode> put(final String _key,final ByteBuffer _value)
 	{
+		Either<Error,EditableNode> either = wrap.put(_key,_value);
+		if(either.isA()){
+			return either;
+		}
+		
 		Operation opPut = new SetAttributeOperation(){
 			@Override
 			public String getKey(){
@@ -57,8 +71,8 @@
 		};
 		
 		Logger newLog = log.add(opPut);
-		EditableNode newWrap = wrap.put(_key,_value);
+		EditableNode newLoggingNode = new LoggingNode(either.b(),newLog);
 		
-		return new LoggingNode(newWrap,newLog);
+		return DefaultEither.newB(newLoggingNode);
 	}
 }
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/impl/logger/LoggingChildren.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/impl/logger/LoggingChildren.java	Mon Jan 07 23:22:36 2013 +0900
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/impl/logger/LoggingChildren.java	Thu Jan 10 23:22:42 2013 +0900
@@ -8,6 +8,8 @@
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.operations.Operation;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.trasnformer.EditableChildren;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.trasnformer.EditableNode;
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.DefaultEither;
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.Either;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.IterableWrapper;
 
 public class LoggingChildren implements EditableChildren
@@ -35,8 +37,13 @@
 	}
 
 	@Override
-	public EditableNode addNewChildAt(final int _pos)
+	public Either<Error,EditableNode> addNewChildAt(final int _pos)
 	{
+		Either<Error,EditableNode> either = wrap.addNewChildAt(_pos);
+		if(either.isA()){
+			return either;
+		}
+		
 		Operation opAddChild = new AppendChildAtOperation(){
 			@Override
 			public int position(){
@@ -45,14 +52,20 @@
 		};
 		
 		Logger newLog = log.add(opAddChild);
-		EditableNode newWrap = wrap.addNewChildAt(_pos);
+		EditableNode newWrap = either.b();
+		EditableNode newLoggingNode = new LoggingNode(newWrap,newLog);
 		
-		return new LoggingNode(newWrap,newLog);
+		return DefaultEither.newB(newLoggingNode);
 	}
 
 	@Override
-	public EditableNode deleteChildAt(final int _pos)
+	public Either<Error,EditableNode> deleteChildAt(final int _pos)
 	{
+		Either<Error,EditableNode> either = wrap.deleteChildAt(_pos);
+		if(either.isA()){
+			return either;
+		}
+		
 		Operation opDeleteChild = new DeleteChildAtOperation(){
 			@Override
 			public int position(){
@@ -61,8 +74,8 @@
 		};
 		
 		Logger newLog = log.add(opDeleteChild);
-		EditableNode newWrap = wrap.deleteChildAt(_pos);
+		EditableNode newLoggingNode = new LoggingNode(either.b(),newLog);
 		
-		return new LoggingNode(newWrap,newLog);
+		return DefaultEither.newB(newLoggingNode);
 	}
 }
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/AppendChildAt.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/AppendChildAt.java	Mon Jan 07 23:22:36 2013 +0900
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/AppendChildAt.java	Thu Jan 10 23:22:42 2013 +0900
@@ -1,5 +1,8 @@
 package jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.trasnformer;
 
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.DefaultEither;
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.Either;
+
 public class AppendChildAt implements NodeEditor
 {
 	private final int pos;
@@ -10,9 +13,14 @@
 	}
 
 	@Override
-	public NodeEditResult edit(EditableNode _e)
+	public Either<Error,EditableNode> edit(EditableNode _e)
 	{
-		EditableNode node = _e.getChildren().addNewChildAt(pos);
-		return new DefaultNodeEditResult(NodeEditResultStatus.SUCCESS,node);
+		Either<Error,EditableNode> either = _e.getChildren().addNewChildAt(pos);
+		if(either.isA()){
+			// error
+			
+		}
+		
+		return DefaultEither.newB(either.b());
 	}
 }
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/DefaultEditableChildren.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/DefaultEditableChildren.java	Mon Jan 07 23:22:36 2013 +0900
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/DefaultEditableChildren.java	Thu Jan 10 23:22:42 2013 +0900
@@ -5,6 +5,7 @@
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.core.Node;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.operations.AppendChildAtOperation;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.operations.Operation;
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.Either;
 
 public class DefaultEditableChildren implements EditableChildren
 {
@@ -30,7 +31,7 @@
 	}
 
 	@Override
-	public EditableNode addNewChildAt(final int _pos)
+	public Either<Error,EditableNode> addNewChildAt(final int _pos)
 	{
 		AppendChildAtOperation op = new AppendChildAtOperation(){
 			@Override
@@ -43,7 +44,7 @@
 	}
 
 	@Override
-	public EditableNode deleteChildAt(int _pos)
+	public Either<Error,EditableNode> deleteChildAt(int _pos)
 	{
 		return null;
 	}
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/DeleteAttribute.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/DeleteAttribute.java	Mon Jan 07 23:22:36 2013 +0900
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/DeleteAttribute.java	Thu Jan 10 23:22:42 2013 +0900
@@ -1,5 +1,7 @@
 package jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.trasnformer;
 
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.Either;
+
 public class DeleteAttribute implements NodeEditor
 {
 	private final String key;
@@ -10,9 +12,8 @@
 	}
 
 	@Override
-	public NodeEditResult edit(EditableNode _e)
+	public Either<Error,EditableNode> edit(EditableNode _e)
 	{
-		EditableNode node = _e.getAttributes().delete(key);
-		return new DefaultNodeEditResult(NodeEditResultStatus.SUCCESS,node);
+		return _e.getAttributes().delete(key);
 	}
 }
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/DeleteChildAt.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/DeleteChildAt.java	Mon Jan 07 23:22:36 2013 +0900
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/DeleteChildAt.java	Thu Jan 10 23:22:42 2013 +0900
@@ -1,5 +1,7 @@
 package jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.trasnformer;
 
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.Either;
+
 public class DeleteChildAt implements NodeEditor
 {
 	private final int pos;
@@ -10,9 +12,8 @@
 	}
 
 	@Override
-	public NodeEditResult edit(EditableNode _e)
+	public Either<Error,EditableNode> edit(EditableNode _e)
 	{
-		EditableNode node = _e.getChildren().deleteChildAt(pos);
-		return new DefaultNodeEditResult(NodeEditResultStatus.SUCCESS,node);
+		return _e.getChildren().deleteChildAt(pos);
 	}
 }
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/EditableAttributes.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/EditableAttributes.java	Mon Jan 07 23:22:36 2013 +0900
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/EditableAttributes.java	Thu Jan 10 23:22:42 2013 +0900
@@ -3,9 +3,10 @@
 import java.nio.ByteBuffer;
 
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.core.Attributes;
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.Either;
 
 public interface EditableAttributes extends Attributes
 {
-	public EditableNode delete(String _key);
-	public EditableNode put(String _key,ByteBuffer _value);
+	public Either<Error,EditableNode> delete(String _key);
+	public Either<Error,EditableNode> put(String _key,ByteBuffer _value);
 }
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/EditableChildren.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/EditableChildren.java	Mon Jan 07 23:22:36 2013 +0900
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/EditableChildren.java	Thu Jan 10 23:22:42 2013 +0900
@@ -1,9 +1,10 @@
 package jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.trasnformer;
 
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.core.Children;
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.Either;
 
 public interface EditableChildren extends Children
 {
-	public EditableNode addNewChildAt(int _pos);
-	public EditableNode deleteChildAt(int _pos);
+	public Either<Error,EditableNode> addNewChildAt(int _pos);
+	public Either<Error,EditableNode> deleteChildAt(int _pos);
 }
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/NodeEditResultStatus.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/NodeEditResultStatus.java	Mon Jan 07 23:22:36 2013 +0900
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,6 +0,0 @@
-package jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.trasnformer;
-
-public enum NodeEditResultStatus
-{
-	SUCCESS,FAIL;
-}
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/NodeEditor.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/NodeEditor.java	Mon Jan 07 23:22:36 2013 +0900
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/NodeEditor.java	Thu Jan 10 23:22:42 2013 +0900
@@ -1,6 +1,8 @@
 package jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.trasnformer;
 
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.Either;
+
 public interface NodeEditor
 {
-	public NodeEditResult edit(EditableNode _e);
+	public Either<Error,EditableNode> edit(EditableNode _e);
 }
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/NodeEditorError.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/NodeEditorError.java	Thu Jan 10 23:22:42 2013 +0900
@@ -0,0 +1,9 @@
+package jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.trasnformer;
+
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.Error;
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.DefaultError;
+
+public class NodeEditorError
+{
+	public static final Error INDEX_OUT_OF_BOUNDS = new DefaultError();
+}
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/SetAttribute.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/SetAttribute.java	Mon Jan 07 23:22:36 2013 +0900
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/trasnformer/SetAttribute.java	Thu Jan 10 23:22:42 2013 +0900
@@ -2,6 +2,8 @@
 
 import java.nio.ByteBuffer;
 
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.Either;
+
 public class SetAttribute implements NodeEditor
 {
 	private final String key;
@@ -14,9 +16,9 @@
 	}
 
 	@Override
-	public NodeEditResult edit(EditableNode _e)
+	public Either<Error,EditableNode> edit(EditableNode _e)
 	{
 		EditableAttributes attrs = _e.getAttributes();
-		return new DefaultNodeEditResult(NodeEditResultStatus.SUCCESS,attrs.put(key,value));
+		return attrs.put(key,value);
 	}
 }
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/traverser/DefaultTraversal.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/traverser/DefaultTraversal.java	Thu Jan 10 23:22:42 2013 +0900
@@ -0,0 +1,22 @@
+package jp.ac.u_ryukyu.ie.cr.shoshi.jungle.traverser;
+
+import java.util.Iterator;
+
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.core.Node;
+
+public class DefaultTraversal implements Traversal
+{
+
+	@Override
+	public Iterator<Node> iterator()
+	{
+		return null;
+	}
+
+	@Override
+	public Node destination()
+	{
+		return null;
+	}
+
+}
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/traverser/DefaultTraverser.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/traverser/DefaultTraverser.java	Mon Jan 07 23:22:36 2013 +0900
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/traverser/DefaultTraverser.java	Thu Jan 10 23:22:42 2013 +0900
@@ -1,30 +1,51 @@
 package jp.ac.u_ryukyu.ie.cr.shoshi.jungle.traverser;
 
 import java.util.Iterator;
-
 import fj.P;
 import fj.P2;
 import fj.data.List;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.core.Node;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.core.Tree;
-import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.IterableWrapper;
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.IterableConverter;
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.IterableConverter.Converter;
 
 public class DefaultTraverser implements Traverser
 {
 	@Override
-	public Iterable<TraverseResult> traverse(Tree _tree, TraverseEvaluator _evaluator)
+	public Iterable<Traversal> traverse(Tree _tree, TraverseEvaluator _evaluator)
 	{
 		Node root = _tree.getRoot();
 		
 		List<Node> current = List.nil();
 		TraverseEvaluator evaluator = _evaluator;
 		
-		List<TraverseResultImpl> totalResult = _traverse(current,root,evaluator);
+		List<List<Node>> totalResult = _traverse(current,root,evaluator);
 		
-		return new IterableWrapper<TraverseResult>(totalResult);
+		Converter<Traversal,List<Node>> converter = new IterableConverter.Converter<Traversal,List<Node>>(){
+			@Override
+			public Traversal conv(final List<Node> _b)
+			{
+				Traversal t = new Traversal(){
+					@Override
+					public Iterator<Node> iterator(){
+						return _b.iterator();
+					}
+
+					@Override
+					public Node destination() {
+						return _b.last();
+					}
+					
+				};
+				
+				return t;
+			}
+		};
+		
+		return new IterableConverter<Traversal,List<Node>>(totalResult,converter);
 	}
 	
-	private List<TraverseResultImpl> _traverse(List<Node> _path,Node _current,TraverseEvaluator _evaluator)
+	private List<List<Node>> _traverse(List<Node> _path,Node _current,TraverseEvaluator _evaluator)
 	{
 		List<Node> currentPath = _path.snoc(_current);
 		
@@ -46,36 +67,18 @@
 			}
 		}
 		
-		List<TraverseResultImpl> totalResult = List.nil();
+		List<List<Node>> totalResult = List.nil();
 		for(P2<Node,Evaluation> next : accepted){
 			Node node = next._1();
 			TraverseEvaluator evaluator = next._2().evaluator();
-			List<TraverseResultImpl> result = _traverse(currentPath,node,evaluator);
-			totalResult = totalResult.append(result);
+			List<List<Node>> result = _traverse(currentPath,node,evaluator);
+			
+			
+			for(List<Node> list : result){
+				totalResult = totalResult.snoc(list.cons(_current));
+			}
 		}
 		
 		return totalResult;
 	}
-	
-	public static class TraverseResultImpl implements TraverseResult
-	{
-		private final List<Node> result;
-		
-		public TraverseResultImpl(List<Node> _result)
-		{
-			result = _result;
-		}
-
-		@Override
-		public Iterator<Node> iterator()
-		{
-			return result.iterator();
-		}
-		
-		@Override
-		public Node destination()
-		{
-			return result.last();
-		}
-	}
 }
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/traverser/Traversable.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/traverser/Traversable.java	Mon Jan 07 23:22:36 2013 +0900
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/traverser/Traversable.java	Thu Jan 10 23:22:42 2013 +0900
@@ -2,5 +2,5 @@
 
 public interface Traversable
 {
-	public Iterable<TraverseResult> traverse(TraverseEvaluator _e);
+	public Iterable<Traversal> traverse(TraverseEvaluator _e);
 }
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/traverser/Traversal.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/traverser/Traversal.java	Thu Jan 10 23:22:42 2013 +0900
@@ -0,0 +1,8 @@
+package jp.ac.u_ryukyu.ie.cr.shoshi.jungle.traverser;
+
+import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.core.Node;
+
+public interface Traversal extends Iterable<Node>
+{
+	public Node destination();
+}
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/traverser/TraverseEvaluator.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/traverser/TraverseEvaluator.java	Mon Jan 07 23:22:36 2013 +0900
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/traverser/TraverseEvaluator.java	Thu Jan 10 23:22:42 2013 +0900
@@ -1,7 +1,5 @@
 package jp.ac.u_ryukyu.ie.cr.shoshi.jungle.traverser;
 
-import java.util.Iterator;
-
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.core.Node;
 
 public interface TraverseEvaluator
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/traverser/TraverseResult.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/traverser/TraverseResult.java	Mon Jan 07 23:22:36 2013 +0900
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,8 +0,0 @@
-package jp.ac.u_ryukyu.ie.cr.shoshi.jungle.traverser;
-
-import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.core.Node;
-
-public interface TraverseResult extends Iterable<Node>
-{
-	public Node destination();
-}
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/traverser/Traverser.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/traverser/Traverser.java	Mon Jan 07 23:22:36 2013 +0900
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/traverser/Traverser.java	Thu Jan 10 23:22:42 2013 +0900
@@ -4,5 +4,5 @@
 
 public interface Traverser
 {
-	public Iterable<TraverseResult> traverse(Tree _tree,TraverseEvaluator _evaluator);
+	public Iterable<Traversal> traverse(Tree _tree,TraverseEvaluator _evaluator);
 }
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/util/DefaultEither.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/util/DefaultEither.java	Mon Jan 07 23:22:36 2013 +0900
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/util/DefaultEither.java	Thu Jan 10 23:22:42 2013 +0900
@@ -5,10 +5,20 @@
 	private final A theA;
 	private final B theB;
 	
-	public DefaultEither(A _theA)
+	private DefaultEither(A _theA,B _theB)
 	{
 		theA = _theA;
-		theB = null;
+		theB = _theB;
+	}
+	
+	public static final <A,B> DefaultEither<A,B> newA(A _theA)
+	{
+		return new DefaultEither<A,B>(_theA,null);
+	}
+	
+	public static final <A,B> DefaultEither<A,B> newB(B _theB)
+	{
+		return new DefaultEither<A,B>(null,_theB);
 	}
 
 	@Override
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/util/DefaultError.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/util/DefaultError.java	Thu Jan 10 23:22:42 2013 +0900
@@ -0,0 +1,5 @@
+package jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util;
+
+public class DefaultError implements Error
+{
+}
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/util/Error.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/util/Error.java	Thu Jan 10 23:22:42 2013 +0900
@@ -0,0 +1,5 @@
+package jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util;
+
+public interface Error {
+
+}
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/util/IterableConverter.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/util/IterableConverter.java	Thu Jan 10 23:22:42 2013 +0900
@@ -0,0 +1,56 @@
+package jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util;
+
+import java.util.Iterator;
+
+public class IterableConverter<A,B> implements Iterable<A>
+{
+	private final Iterable<B> iterable;
+	private final Converter<A,B> converter;
+	
+	public IterableConverter(Iterable<B> _iterable,Converter<A,B> _converter)
+	{
+		iterable = _iterable;
+		converter = _converter;
+	}
+	
+	@Override
+	public Iterator<A> iterator()
+	{
+		return new IteratorConverter<A,B>(iterable.iterator(),converter);
+	}
+	
+	private static final class IteratorConverter<A,B> implements Iterator<A>
+	{
+		private final Iterator<B> iterator;
+		private final Converter<A,B> converter;
+		
+		public IteratorConverter(Iterator<B> _iterator,Converter<A,B> _converter)
+		{
+			iterator = _iterator;
+			converter = _converter;
+		}
+		
+		@Override
+		public boolean hasNext()
+		{
+			return iterator.hasNext();
+		}
+
+		@Override
+		public A next()
+		{
+			return converter.conv(iterator.next());
+		}
+
+		@Override
+		public void remove()
+		{
+			iterator.remove();
+		}
+	}
+
+	public static interface Converter<A,B>
+	{
+		public A conv(B _b);
+	}
+}
diff -r 9fd57b7c6adb -r 3ef2a66a8c5d src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/util/IterableWrapper.java
--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/util/IterableWrapper.java	Mon Jan 07 23:22:36 2013 +0900
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/util/IterableWrapper.java	Thu Jan 10 23:22:42 2013 +0900
@@ -10,7 +10,7 @@
 	{
 		iterable = _iterable;
 	}
-
+	
 	@Override
 	public Iterator<T> iterator()
 	{