Formatter checkpoint.

editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/formatter/edit/StringEditOperation.java

Index: editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/formatter/edit/StringEditOperation.java
===================================================================
--- editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/formatter/edit/StringEditOperation.java	(revision 0)
+++ editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/formatter/edit/StringEditOperation.java	(revision 0)
@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2012, the Dart project authors.
+ * 
+ * Licensed under the Eclipse Public License v1.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ * 
+ * http://www.eclipse.org/legal/epl-v10.html
+ * 
+ * Unless required by applicable law or agreed to in writing, software distributed under the License
+ * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+ * or implied. See the License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.google.dart.engine.internal.formatter.edit;
+
+import com.google.dart.engine.formatter.edit.Edit;
+import com.google.dart.engine.formatter.edit.EditOperation;
+
+import java.util.List;
+
+/**
+ * A simple un-optimized string edit operation implementation.
+ */
+public class StringEditOperation implements EditOperation<String, String> {
+
+  private final List<Edit> edits;
+
+  /**
+   * Create an edit operation for the given sequence of edits.
+   * 
+   * @param edits the sequence of edits to apply
+   */
+  public StringEditOperation(List<Edit> edits) {
+    this.edits = edits;
+  }
+
+  @Override
+  public String applyTo(String document) {
+
+    StringBuilder builder = new StringBuilder(document);
+
+    Edit edit;
+
+    for (int i = edits.size() - 1; i >= 0; --i) {
+      edit = edits.get(i);
+      builder.replace(edit.offset, edit.offset + edit.length, edit.replacement);
+    }
+
+    return builder.toString();
+  }
+
+}