/*
   * Evaluates possible return expressions. The favourite expression is returned.
   */
  private Expression evaluateReturnExpressions(
      AST ast, ITypeBinding returnBinding, int returnOffset) {
    CompilationUnit root = (CompilationUnit) fMethodDecl.getRoot();

    Expression result = null;
    if (returnBinding != null) {
      ScopeAnalyzer analyzer = new ScopeAnalyzer(root);
      IBinding[] bindings =
          analyzer.getDeclarationsInScope(
              returnOffset, ScopeAnalyzer.VARIABLES | ScopeAnalyzer.CHECK_VISIBILITY);
      for (int i = 0; i < bindings.length; i++) {
        IVariableBinding curr = (IVariableBinding) bindings[i];
        ITypeBinding type = curr.getType();
        if (type != null && type.isAssignmentCompatible(returnBinding) && testModifier(curr)) {
          if (result == null) {
            result = ast.newSimpleName(curr.getName());
          }
          addLinkedPositionProposal(RETURN_EXPRESSION_KEY, curr.getName(), null);
        }
      }
    }
    Expression defaultExpression =
        ASTNodeFactory.newDefaultExpression(
            ast, fMethodDecl.getReturnType2(), fMethodDecl.getExtraDimensions());
    addLinkedPositionProposal(RETURN_EXPRESSION_KEY, ASTNodes.asString(defaultExpression), null);
    if (result == null) {
      return defaultExpression;
    }
    return result;
  }
 private String getConstantTypeName() throws JavaModelException {
   return ASTNodes.asString(getConstantType());
 }
  private ExtractConstantDescriptor createRefactoringDescriptor() {
    final Map<String, String> arguments = new HashMap<>();
    String project = null;
    IJavaProject javaProject = fCu.getJavaProject();
    if (javaProject != null) project = javaProject.getElementName();
    int flags =
        JavaRefactoringDescriptor.JAR_REFACTORING | JavaRefactoringDescriptor.JAR_SOURCE_ATTACHMENT;
    if (JdtFlags.getVisibilityCode(fVisibility) != Modifier.PRIVATE)
      flags |= RefactoringDescriptor.STRUCTURAL_CHANGE;

    final String expression = ASTNodes.asString(fSelectedExpression.getAssociatedExpression());
    final String description =
        Messages.format(
            RefactoringCoreMessages.ExtractConstantRefactoring_descriptor_description_short,
            BasicElementLabels.getJavaElementName(fConstantName));
    final String header =
        Messages.format(
            RefactoringCoreMessages.ExtractConstantRefactoring_descriptor_description,
            new String[] {
              BasicElementLabels.getJavaElementName(fConstantName),
              BasicElementLabels.getJavaCodeString(expression)
            });
    final JDTRefactoringDescriptorComment comment =
        new JDTRefactoringDescriptorComment(project, this, header);
    comment.addSetting(
        Messages.format(
            RefactoringCoreMessages.ExtractConstantRefactoring_constant_name_pattern,
            BasicElementLabels.getJavaElementName(fConstantName)));
    comment.addSetting(
        Messages.format(
            RefactoringCoreMessages.ExtractConstantRefactoring_constant_expression_pattern,
            BasicElementLabels.getJavaCodeString(expression)));
    String visibility = fVisibility;
    if ("".equals(visibility)) // $NON-NLS-1$
    visibility = RefactoringCoreMessages.ExtractConstantRefactoring_default_visibility;
    comment.addSetting(
        Messages.format(
            RefactoringCoreMessages.ExtractConstantRefactoring_visibility_pattern, visibility));
    if (fReplaceAllOccurrences)
      comment.addSetting(RefactoringCoreMessages.ExtractConstantRefactoring_replace_occurrences);
    if (fQualifyReferencesWithDeclaringClassName)
      comment.addSetting(RefactoringCoreMessages.ExtractConstantRefactoring_qualify_references);
    arguments.put(
        JavaRefactoringDescriptorUtil.ATTRIBUTE_INPUT,
        JavaRefactoringDescriptorUtil.elementToHandle(project, fCu));
    arguments.put(JavaRefactoringDescriptorUtil.ATTRIBUTE_NAME, fConstantName);
    arguments.put(
        JavaRefactoringDescriptorUtil.ATTRIBUTE_SELECTION,
        new Integer(fSelectionStart).toString()
            + " "
            + new Integer(fSelectionLength).toString()); // $NON-NLS-1$
    arguments.put(ATTRIBUTE_REPLACE, Boolean.valueOf(fReplaceAllOccurrences).toString());
    arguments.put(
        ATTRIBUTE_QUALIFY, Boolean.valueOf(fQualifyReferencesWithDeclaringClassName).toString());
    arguments.put(
        ATTRIBUTE_VISIBILITY, new Integer(JdtFlags.getVisibilityCode(fVisibility)).toString());

    ExtractConstantDescriptor descriptor =
        RefactoringSignatureDescriptorFactory.createExtractConstantDescriptor(
            project, description, comment.asString(), arguments, flags);
    return descriptor;
  }