private void replaceExpressionsWithConstant() throws JavaScriptModelException {
    ASTRewrite astRewrite = fCuRewrite.getASTRewrite();
    AST ast = astRewrite.getAST();

    IASTFragment[] fragmentsToReplace = getFragmentsToReplace();
    for (int i = 0; i < fragmentsToReplace.length; i++) {
      IASTFragment fragment = fragmentsToReplace[i];

      SimpleName ref = ast.newSimpleName(fConstantName);
      Name replacement = ref;
      if (qualifyReferencesWithDeclaringClassName()) {
        replacement =
            ast.newQualifiedName(ast.newSimpleName(getContainingTypeBinding().getName()), ref);
      }
      TextEditGroup description =
          fCuRewrite.createGroupDescription(
              RefactoringCoreMessages.ExtractConstantRefactoring_replace);

      fragment.replace(astRewrite, replacement, description);
      if (fLinkedProposalModel != null)
        fLinkedProposalModel
            .getPositionGroup(KEY_NAME, true)
            .addPosition(astRewrite.track(ref), false);
    }
  }
  private IExpressionFragment getSelectedExpression() throws JavaScriptModelException {
    if (fSelectedExpression != null) return fSelectedExpression;

    IASTFragment selectedFragment =
        ASTFragmentFactory.createFragmentForSourceRange(
            new SourceRange(fSelectionStart, fSelectionLength), fCuRewrite.getRoot(), fCu);

    if (selectedFragment instanceof IExpressionFragment
        && !Checks.isInsideJavadoc(selectedFragment.getAssociatedNode())) {
      fSelectedExpression = (IExpressionFragment) selectedFragment;
    }

    return fSelectedExpression;
  }
 // !! - like one in ExtractTempRefactoring
 private static boolean canReplace(IASTFragment fragment) {
   ASTNode node = fragment.getAssociatedNode();
   ASTNode parent = node.getParent();
   if (parent instanceof VariableDeclarationFragment) {
     VariableDeclarationFragment vdf = (VariableDeclarationFragment) parent;
     if (node.equals(vdf.getName())) return false;
   }
   if (parent instanceof ExpressionStatement) return false;
   if (parent instanceof SwitchCase) return false;
   return true;
 }