Quick Assist for creating a constructor for selected final fields.

pkg/analysis_server/lib/src/services/correction/util.dart

 // 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.src.correction.util;
 
 import 'dart:math';
 
 import 'package:analysis_server/src/protocol.dart'
     show SourceChange, SourceEdit;
@@ skipping 1043 matching lines @@
     String trimmedText = getRangeText(range).trim();
     // may be whitespace
     if (trimmedText.isEmpty) {
       return true;
     }
     // may be comment
     return TokenUtils.getTokens(trimmedText).isEmpty;
   }
 
   /**
+   * Return the best locations for a new constructor in the given
+   * [classDeclaration].
+   */
+  ConstructorLocation findNewConstructorLocation(
+      ClassDeclaration classDeclaration) {
+    String eol = endOfLine;
+    List<ClassMember> members = classDeclaration.members;
+    // find the last field/constructor
+    ClassMember lastFieldOrConstructor = null;
+    for (ClassMember member in members) {
+      if (member is FieldDeclaration || member is ConstructorDeclaration) {
+        lastFieldOrConstructor = member;
+      } else {
+        break;
+      }
+    }
+    // after the last field/constructor
+    if (lastFieldOrConstructor != null) {
+      return new ConstructorLocation(eol + eol, lastFieldOrConstructor.end, '');
+    }
+    // at the beginning of the class
+    String suffix = members.isEmpty ? '' : eol;
+    return new ConstructorLocation(
+        eol, classDeclaration.leftBracket.end, suffix);
+  }
+
+  /**
    * Returns the source with indentation changed from [oldIndent] to
    * [newIndent], keeping indentation of lines relative to each other.
    */
   String replaceSourceIndent(
       String source, String oldIndent, String newIndent) {
     // prepare STRING token ranges
     List<SourceRange> lineRanges = [];
     {
       List<Token> tokens = TokenUtils.getTokens(source);
       for (Token token in tokens) {
@@ skipping 399 matching lines @@
 
   @override
   Object visitExpression(Expression node) {
     if (node is BinaryExpression && node.operator.type == groupOperatorType) {
       return super.visitNode(node);
     }
     operands.add(node);
     return null;
   }
 }
+
+/**
+ * Describes the location for a newly created [ConstructorDeclaration].
+ */
+class ConstructorLocation {
+  final String prefix;
+  final int offset;
+  final String suffix;
+
+  ConstructorLocation(this.prefix, this.offset, this.suffix);
+}