Initial work on refactorings.

pkg/analysis_services/lib/refactoring/refactoring.dart

Index: pkg/analysis_services/lib/refactoring/refactoring.dart
diff --git a/pkg/analysis_services/lib/refactoring/refactoring.dart b/pkg/analysis_services/lib/refactoring/refactoring.dart
new file mode 100644
index 0000000000000000000000000000000000000000..f8a8ee71849df9ed596a839a0afcf33c266d46c7
--- /dev/null
+++ b/pkg/analysis_services/lib/refactoring/refactoring.dart
@@ -0,0 +1,92 @@
+// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library services.refactoring;
+
+import 'package:analysis_services/correction/change.dart';
+import 'package:analysis_services/correction/status.dart';
+import 'package:analysis_services/search/search_engine.dart';
+import 'package:analysis_services/src/refactoring/rename_local.dart';
+import 'package:analyzer/src/generated/element.dart';
+
+
+/**
+ * Abstract interface for all refactorings.
+ */
+abstract class Refactoring {
+  /**
+   * Returns the human readable name of this [Refactoring].
+   */
+  String get refactoringName;
+
+  /**
+   * Checks all conditions - [checkInitialConditions] and
+   * [checkFinalConditions] to decide if refactoring can be performed.
+   */
+  RefactoringStatus checkAllConditions();
+
+  /**
+   * Validates environment to check if this refactoring can be performed.
+   *
+   * This check may be slow, because many refactorings use search engine.
+   */
+  RefactoringStatus checkFinalConditions();
+
+  /**
+   * Validates arguments to check if this refactoring can be performed.
+   *
+   * This check should be quick because it is used often as arguments change.
+   */
+  RefactoringStatus checkInitialConditions();
+
+  /**
+   * Returns the [Change] to apply to perform this refactoring.
+   */
+  Change createChange();
+
+  /**
+   * Returs `true` if the [Change] created by refactoring may be unsafe,
+   * so we want user to review the [Change] to ensure that he understands it.
+   */
+  bool requiresPreview();
+}
+
+
+/**
+ * Abstract [Refactoring] for renaming some [Element].
+ */
+abstract class RenameRefactoring implements Refactoring {
+  /**
+   * Returns a new [RenameRefactoring] instance for renaming [element],
+   * maybe `null` if there is no support for renaming [Element]s of the given
+   * type.
+   */
+  factory RenameRefactoring(SearchEngine searchEngine, Element element) {
+    if (element is LocalElement) {
+      return new RenameLocalRefactoringImpl(searchEngine, element);
+    }
+    return null;
+  }
+
+  /**
+   * Sets the new name for the [Element].
+   */
+  void set newName(String newName);
+
+  /**
+   * Returns the old name of the [Element] being renamed.
+   */
+  String get oldName;
+
+  /**
+   * Validates that the [newName] is a valid identifier and is appropriate for
+   * the type of the [Element] being renamed.
+   *
+   * It does not perform all the checks (such as checking for conflicts with any
+   * existing names in any of the scopes containing the current name), as many
+   * of these checkes require search engine. Use [checkFinalConditions] for this
+   * level of checking.
+   */
+  RefactoringStatus checkNewName();
+}